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1.
Zhonghua Bing Li Xue Za Zhi ; 50(4): 369-375, 2021 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-33831997

RESUMO

Objective: To analyze the expression of mismatch repair (MMR) proteins in colorectal cancers (CRC) and to evaluate the feasibility and potential pitfalls of immunohistochemistry (IHC) analysis for MMR. Methods: The IHC sections for MMR proteins were reviewed in 3 428 cases of resected CRC without neoadjuvant therapy at Tianjin Medical University Cancer Institute and Hospital from July 2014 to October 2018. For the cases with unclear MMR IHC results during the initial review, IHC staining was repeated and microsatellite instability (MSI) analysis was performed. Relationships between the expression of MMR proteins and MSI status as well as the clinicopathological parameters were analyzed. Results: IHC staining for MMR was repeated in 28 (0.8%) cases due to poor quality of original IHC sections. Inconsistent results between the original diagnosis and re-diagnosis were found in 119 (3.5%) cases, mainly resulting from PMS2 and MLH1. Finally, 261 (7.6%) cases of CRC showed mismatch repair deficiency (dMMR), mainly from the deficiency of both MLH1 and PMS2 (43.3%,113/261). In the 14 cases with MSI results, the concordant of MSI and MMR was 13 cases. In the 29 dMMR cases with next generation sequencing (NGS) results, the concordant of MSI-high and dMMR was 93.1%(27/29). The cases with inconsistent results between MSI and MMR showed negative expression of MSH6 or PMS2. Twenty-one CRC showed negative expression of MLH1 and partially positive (or weak positive) expression of PMS2, or negative expression of MSH2 and partially positive (or weak positive) expression of MSH6. Among the 19 cases with MSI results, 16 cases were MSI-high, two cases were MSI-low, and one case was microsatellite stable. Compared with mismatch repair proficiency (pMMR), dMMR was more frequently detected in female patients younger than 50 years old, with family history, at early stage (Ⅰ-Ⅱ) CRC, and in the tumors from right colon,with poor differentiation, or mucinous adenocarcinoma/signet ring cell carcinoma (all P<0.05). Conclusions: At present, IHC staining is a clinically effective and convenient method to detect MMR expression, but the operating process and result assessment remain variable and need to be standardized. MSI analysis can be performed in the difficult-to-evaluate cases for MMR to enhance prognostic evaluation and treatment option.


Assuntos
Neoplasias Colorretais , Reparo de Erro de Pareamento de DNA , Neoplasias Colorretais/genética , Reparo de Erro de Pareamento de DNA/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/genética , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Estudos Retrospectivos
2.
Zhonghua Bing Li Xue Za Zhi ; 50(5): 470-475, 2021 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-33915653

RESUMO

Objective: To analyze the microsatellite instability (MSI) status in endometrioid endometrial carcinoma (EEC) with deficient mismatch repair (dMMR) and to explore the concordance between MSI next generation sequencing (NGS)/PCR and MMR immunohistochemistry (IHC) results. Methods: Sixty dMMR EEC cases by IHC from November 2017 to February 2019 were selected in the Department of Pathology, Peking Union Medical College Hospital. Two pathologists reviewed the IHC results. The MSI status and the germline/somatic mutational status of MMR genes were analyzed by NGS. MLH1 promoter methylation status was determined by methylation-specific PCR (MSP) in cases with MLH1 protein deficiency. In cases with discrepant results between MMR IHC and MSI NGS, the MSI status was detected again by PCR, and the reasons for the discrepancy were discussed with gene mutation and MLH1 promoter methylation results. Results: Among 60 dMMR EEC specimens, 3 samples were re-assigned as proficient mismatch repair (pMMR) after pathological review, and identified as MSS by NGS. Another 3 dMMR cases showed MSI-uncertainty (MSI-U) by NGS due to insufficient tumor content. In the remaining 54 cases, the concordance between MMR IHC and MSI NGS was 87% (47/54). The seven discrepant cases was further analyzed: in 5 discrepant cases with MLH1/PMS2 protein loss, one case did not have enough samples for detection, one case was MSI-H, and the remaining three cases were MSS by PCR. All these 5 cases with MLH1/PMS2 protein loss showed the MLH1 promoter hypermethylation, two of which also had a somatic mutation in the MSH2 gene. The two discrepant cases with MSH6 protein loss were both MSS by PCR, one of which was considered to have Lynch syndrome with germline mutation in MSH6 gene. Conclusions: Although the overwhelming majority of dMMR EEC cases by IHC shows MSI-H by NGS/PCR, there are uncommon discrepant dMMR EEC cases with MSS. They are mostly found in cases with MLH1/PMS2 protein loss caused by MLH1 promoter hypermethylation and rarely related to Lynch syndrome. Both MMR IHC and MSI NGS/PCR tests have their advantages and disadvantages, complimentary to each other.


Assuntos
Carcinoma Endometrioide , Instabilidade de Microssatélites , Reparo de Erro de Pareamento de DNA/genética , Feminino , Humanos , Imuno-Histoquímica , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/genética , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/genética , Proteína 2 Homóloga a MutS/metabolismo
4.
PLoS One ; 15(10): e0238836, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33095797

RESUMO

Recently, the Cancer Genome Atlas and Asian Cancer Research Group propose two new classifications system of gastric cancer by using multi-platforms of molecular analyses. However, these highly complicated and cost technologies have not yet been translated into full clinical utility. In addition, the clinicians are expected to gain more guidance of treatment for different molecular subtypes. In this study, we developed a panel of gastric cancer patients in population from Southern China using commercially accessible TMA and immunohistochemical technology. A cohort of 259 GC patients was classified into 4 subtypes on the basis of expression of mismatch repair proteins (PMS2, MLH1, MSH2, and MSH6), E-cadherin and p21 protein. We observed that the subtypes presented distinct prognosis. dMMR-like subtype was associated with the best prognosis, and E-cadherin-a subtype was associated with the worst prognosis. Patients with p21-High and p21-Ligh subtypes had intermediate overall survival. In multivariate analysis, the dMMR-like subtype remained an independent prediction power for overall survival in the model. We described a molecular classification of gastric cancers using clinically applicable assay. The biological relevance of the four subtypes was illustrated by significant differences in prognosis. Our molecular classification provided an effective and inexpensive screening tool for improving prognostic models. Nevertheless, our study should be considered preliminary and carries a limited predictive value as a single-center retrospective study.


Assuntos
Proteínas de Neoplasias/metabolismo , Neoplasias Gástricas/classificação , Neoplasias Gástricas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD/metabolismo , Biomarcadores Tumorais/metabolismo , Caderinas/metabolismo , China , Estudos de Coortes , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Reparo de Erro de Pareamento de DNA , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Prognóstico , Estudos Retrospectivos , Neoplasias Gástricas/patologia , Análise Serial de Tecidos
5.
Med Oncol ; 37(7): 63, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32556620

RESUMO

In this retrospective study, we evaluated the predictive role of different immunohistochemical expression (IHC) of the mismatch repair proteins (MMR) in patients with colorectal liver metastasis (CRLM) submitted to liver resection. A total of 108 patients were retrieved, and 15 patients were excluded from the study because of the impossibility to obtain adequate formalin-fixed tissue blocks. The final analysis included 93 patients. Twenty-eight cases (30%) presented a no loss of expression or microsatellite stability (MSS) status, 59 cases (63%) showed a hybrid loss of expression, while 6 cases (7%) presented a complete loss of expression or microsatellite instability status (MSI). Patients with complete or hybrid loss of expression of MMR developed a high intra-hepatic recurrence rate compared to other ones (54% vs 21% OR of 4.278, 95% CI 1.53-11.93) (p = 0.004). The same difference in terms of liver recurrence has been found among patients with R0 resection (50% vs 17% OR of 0.2, 95% CI 0.06-0.65) (p = 0.005). However, there was no difference in terms of disease-free survival and overall survival. Complete or hybrid loss of expression of MMR could be considered a risk factor for intra-hepatic recurrences after liver resections for CRLM.


Assuntos
Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/secundário , Instabilidade de Microssatélites , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/cirurgia , Reparo de Erro de Pareamento de DNA , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteínas MutL/metabolismo , Proteínas de Neoplasias/metabolismo , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
6.
PLoS Genet ; 16(6): e1008902, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32589669

RESUMO

Expansion of a CGG-repeat tract in the 5' untranslated region of the FMR1 gene causes the fragile X-related disorders (FXDs; aka the FMR1 disorders). The expansion mechanism is likely shared by the 35+ other diseases resulting from expansion of a disease-specific microsatellite, but many steps in this process are unknown. We have shown previously that expansion is dependent upon functional mismatch repair proteins, including an absolute requirement for MutLγ, one of the three MutL heterodimeric complexes found in mammalian cells. We demonstrate here that both MutLα and MutLß, the two other MutL complexes present in mammalian cells, are also required for most, if not all, expansions in a mouse embryonic stem cell model of the FXDs. A role for MutLα and MutLß is consistent with human GWA studies implicating these complexes as modifiers of expansion risk in other Repeat Expansion Diseases. The requirement for all three complexes suggests a novel model in which these complexes co-operate to generate expansions. It also suggests that the PMS1 subunit of MutLß may be a reasonable therapeutic target in those diseases in which somatic expansion is an important disease modifier.


Assuntos
Síndrome do Cromossomo X Frágil/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteínas MutL/genética , Expansão das Repetições de Trinucleotídeos/genética , Animais , Linhagem Celular , Reparo de Erro de Pareamento de DNA , Modelos Animais de Doenças , Células-Tronco Embrionárias , Técnicas de Inativação de Genes , Humanos , Camundongos , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteínas MutL/metabolismo
7.
Medicine (Baltimore) ; 99(24): e20554, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32541478

RESUMO

Colorectal cancer (CRC) represents a major malignancy globally, with microsatellite instability as its second top molecular mechanism of carcinogenesis. Immunohistochemical (IHC), whose sensitivity and specificity exceed 90%, is used routinely to detect 4 MMR proteins (MLH1, PMS2, MSH2, and MSH6) for screening mismatch repair system defects. We aimed to assess associations of clinicopathologic characteristics with MMR status in resectable CRC patients.Stage I-III CRC cases administered surgical resection in Zhejiang Cancer Hospital in 2013 to 2015 were retrospectively analyzed. MLH1, MSH2, MSH6, and PMS2 protein amounts were evaluated immunohistochemically. Clinicopathological information, including age, sex, tumor location, histological subclass, disease stage, regional lymph node (LN) metastasis, American Joint Committee on Cancer (AJCC) 8th edition stage, and survival data were retrospectively reviewed.A total of 133 CRC cases were assessed, including 74 (55.6%), 45 (33.8%), 55 (41.4%), and 77 (57.9%) not expressing MLH1, MSH2, MSH6, and PMS2, respectively. There were significant associations of MLH1, MSH2, MSH6, and PMS2 proteins with age and sex (P < .05). MLH1, MSH2, and MSH6 (but not PMS2) showed positive associations with primary tumor location (P < .05). Of the 133 patients, 70 and 63 cases were affected on the right and left sides, respectively; significant associations of primary site with age and sex were observed (P < .05). Regarding the MMR status, MLH1, MSH2, and MSH6 protein expression levels were positively associated with primary site (P < .05). Five-year overall survival (OS) rates were 84.2% and 79.2% in left-side and right-side cases, respectively; 5-year disease-free survival (DFS) rates were 74.0% and 69.8%, respectively. Survival had no differences between left- and right-side patients in terms of OS (P = .318) and DFS (P = .481).These data demonstrate that 4 major dMMR proteins are expressed differently in left- and right-side CRCs, and survival is comparable in right- and left-side resectable CRC cases with dMMR.


Assuntos
Adenocarcinoma/genética , Neoplasias Colorretais/genética , Reparo de Erro de Pareamento de DNA , Enzimas Reparadoras do DNA/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , China/epidemiologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Estudos Retrospectivos , Adulto Jovem
8.
Dis Markers ; 2020: 8360841, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32076465

RESUMO

Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRCs) inherited in an autosomal-dominant manner. Here, we reported a multigeneration Chinese family clinically diagnosed with LS according to the Amsterdam II criteria. To identify the underlying causative gene for LS in this family, whole-exome sequencing (WES) was performed. A germline missense variant (c.2054C>T:p.S685F) in exon 18 of MLH1 was successfully identified by WES. Sanger sequencing verified the results of WES and also confirmed the cosegregation of the MLH1 missense variant in all affected members of the family including two unaffected family members. Bioinformatic tools predicted the identified MLH1 variant as deleterious. Immunohistochemistry (IHC) staining showed loss of MLH1 and PMS2 protein expression. In vitro expression analysis also revealed that the identified MLH1 missense variant (c.2054C>T:p.S685F) results in reduced expression of both MLH1 and PMS2 proteins. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, the missense mutation c.2054C>T in MLH1 was classified as a "pathogenic" variant. Two unaffected family members were later recommended for colonoscopy and other important cancer diagnostic inspections every 1-2 years as both were at higher risk of LS. In conclusion, our findings widen the genotypic spectrum of MLH1 mutations responsible for LS. This study increases the phenotypic spectrum of LS which will certainly help the clinicians in diagnosing LS in multigeneration families. This study also puts emphasis on the importance of genetic counselling for the benefit of asymptomatic carriers of MMR gene variants who are at higher risk of LS.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Proteína 1 Homóloga a MutL/genética , Proteína 1 Homóloga a MutL/metabolismo , Mutação de Sentido Incorreto , Sequenciamento Completo do Exoma/métodos , Adulto , China , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Regulação para Baixo , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Linhagem
9.
Breast Cancer Res Treat ; 179(1): 3-10, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31522348

RESUMO

PURPOSE: Alterations to mismatch repair (MMR) pathways are a known cause of cancer, particularly colorectal and endometrial carcinomas. Recently, checkpoint inhibitors have been approved for use in MMR-deficient cancers of any type (Prasad et al. in JAMA Oncol 4:157-158, 2018). Functional studies in breast cancer have shown associations between MMR loss, resistance to aromatase inhibitors and sensitivity to palbociclib (Haricharan et al. in Cancer Discov 7:1168-1183, 2017). Herein, we investigate the clinical meaning of MMR deficiency in breast cancer by immunohistochemical assessment of MSH2, MSH6, MLH1 and PMS2 on a large series of breast cancers linked to detailed biomarker and long-term outcome data. METHODS: Cases were classified as MMR intact when all four markers expressed nuclear reactivity, but MMR-deficient when at least one of the four biomarkers displayed loss of nuclear staining in the presence of positive internal stromal controls on the tissue microarray core. RESULTS: Among the 1635 cases with interpretable staining, we identified 31 (1.9%) as MMR-deficient. In our cohort, MMR deficiency was present across all major breast cancer subtypes, and was associated with high-grade, low-progesterone receptor expression and high tumor-infiltrating lymphocyte counts. MMR deficiency is significantly associated with inferior overall (HR 2.29, 95% CI 1.02-5.17, p = 0.040) and disease-specific survival (HR 2.71, 95% CI 1.00-7.35, p = 0.042) in the 431 estrogen receptor-positive patients who were uniformly treated with tamoxifen as their sole adjuvant systemic therapy. CONCLUSION: Overall, this study supports the concept that breast cancer patients with MMR deficiency as assessed by immunohistochemistry may be good candidates for alternative treatment approaches such as immune checkpoint or CDK4 inhibitors.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Ligação a DNA/metabolismo , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Neoplasias da Mama/patologia , Colúmbia Britânica , Núcleo Celular/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Gradação de Tumores , Receptores de Progesterona/metabolismo , Análise de Sobrevida , Análise Serial de Tecidos
10.
J Biol Chem ; 295(51): 17460-17475, 2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33453991

RESUMO

Homologous recombination (HR) repairs DNA double-strand breaks using intact homologous sequences as template DNA. Broken DNA and intact homologous sequences form joint molecules (JMs), including Holliday junctions (HJs), as HR intermediates. HJs are resolved to form crossover and noncrossover products. A mismatch repair factor, MLH3 endonuclease, produces the majority of crossovers during meiotic HR, but it remains elusive whether mismatch repair factors promote HR in nonmeiotic cells. We disrupted genes encoding the MLH3 and PMS2 endonucleases in the human B cell line, TK6, generating null MLH3-/- and PMS2-/- mutant cells. We also inserted point mutations into the endonuclease motif of MLH3 and PMS2 genes, generating endonuclease death MLH3DN/DN and PMS2EK/EK cells. MLH3-/- and MLH3DN/DN cells showed a very similar phenotype, a 2.5-fold decrease in the frequency of heteroallelic HR-dependent repair of restriction enzyme-induced double-strand breaks. PMS2-/- and PMS2EK/EK cells showed a phenotype very similar to that of the MLH3 mutants. These data indicate that MLH3 and PMS2 promote HR as an endonuclease. The MLH3DN/DN and PMS2EK/EK mutations had an additive effect on the heteroallelic HR. MLH3DN/DN/PMS2EK/EK cells showed normal kinetics of γ-irradiation-induced Rad51 foci but a significant delay in the resolution of Rad51 foci and a 3-fold decrease in the number of cisplatin-induced sister chromatid exchanges. The ectopic expression of the Gen1 HJ re-solvase partially reversed the defective heteroallelic HR of MLH3DN/DN/PMS2EK/EK cells. Taken together, we propose that MLH3 and PMS2 promote HR as endonucleases, most likely by processing JMs in mammalian somatic cells.


Assuntos
Recombinação Homóloga , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteínas MutL/metabolismo , Camptotecina/farmacologia , Linhagem Celular , Quebras de DNA de Cadeia Dupla , Reparo do DNA , DNA Cruciforme , Fase G2 , Raios gama , Humanos , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteínas MutL/genética , Mutação , Ftalazinas/farmacologia , Piperazinas/farmacologia
11.
Elife ; 82019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31697235

RESUMO

Defective mismatch repair leads to increased mutation rates, and germline loss-of-function variants in the repair component MLH1 cause the hereditary cancer predisposition disorder known as Lynch syndrome. Early diagnosis is important, but complicated by many variants being of unknown significance. Here we show that a majority of the disease-linked MLH1 variants we studied are present at reduced cellular levels. We show that destabilized MLH1 variants are targeted for chaperone-assisted proteasomal degradation, resulting also in degradation of co-factors PMS1 and PMS2. In silico saturation mutagenesis and computational predictions of thermodynamic stability of MLH1 missense variants revealed a correlation between structural destabilization, reduced steady-state levels and loss-of-function. Thus, we suggest that loss of stability and cellular degradation is an important mechanism underlying many MLH1 variants in Lynch syndrome. Combined with analyses of conservation, the thermodynamic stability predictions separate disease-linked from benign MLH1 variants, and therefore hold potential for Lynch syndrome diagnostics.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/patologia , Proteína 1 Homóloga a MutL/química , Proteína 1 Homóloga a MutL/metabolismo , Dobramento de Proteína , Proteólise , Linhagem Celular , Biologia Computacional , Humanos , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteínas MutL/metabolismo , Proteínas de Neoplasias/metabolismo , Conformação Proteica , Estabilidade Proteica
12.
Appl Immunohistochem Mol Morphol ; 27(9): 678-682, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31567138

RESUMO

INTRODUCTION: DNA mismatch repair (MMR) deficiency is associated with increased risk of developing several types of cancer and is the most common cause of hereditary endometrial cancer. Identification of the microsatellite instability (MSI) phenotype in endometrial carcinoma is important given that such tumors are frequent. OBJECTIVE: The objective of this study was to assess the utility of immunohistochemistry (IHC), a simple and fast technique, in detecting MSI status in endometrial carcinoma and evaluate the correlation between the MSI phenotype and the various anatomo-clinical parameters. METHODS: IHC expression of 4 markers (MLH1, MSH2, PMS2, and MSH6) was studied. For all IHC markers, a combined score based on the intensity of nuclear labeling and the percentage of labeled cells was defined to establish a score. Correlation between MSI phenotype and different clinicopathologic parameters was evaluated using statistical analysis (software STATA and the Fisher exact test). RESULTS: The mean age of the patients was 58.6 years. Positive staining was highly extended (score 3) with 79% to 100% of marked cells. Less than 10% of positive tumor cells were seen in 3% of cases for MSH6 and PMS2. Abnormal MMR IHC was detected in 10 cases (22.22%). Seven tumors showed loss of MLH1/PMS2. The loss of MSH2/MSH6 was observed in 1 case. The loss of MLH1 or PMS2 was seen only in 2 cases. The number of MSI positive status was 10 cases (22.7%). Correlation between clinicopathologic parameters showed MMR deficiency was significantly associated with low-grade tumor and localized stage. There was no positive correlation between age, histologic subtype, or myometrium invasion. CONCLUSIONS: In summary, detection of DNA MMR deficiencies by IHC can effectively diagnose the MSI phenotype in endometrial carcinoma. Correlation between clinicopathologic parameters showed MMR deficiency was significantly associated with low-grade tumor and localized stage.


Assuntos
Neoplasias Encefálicas/diagnóstico , Neoplasias Colorretais/diagnóstico , Neoplasias do Endométrio/diagnóstico , Imuno-Histoquímica/métodos , Síndromes Neoplásicas Hereditárias/diagnóstico , Coloração e Rotulagem/métodos , Biomarcadores Tumorais/metabolismo , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Estadiamento de Neoplasias , Fenótipo
13.
Cancer Med ; 8(12): 5534-5543, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31386297

RESUMO

BACKGROUND: Lynch syndrome (LS) is the commonest inherited cancer syndrome caused by pathogenic variants of germline DNA mismatch repair (g.MMR) genes. Genome-wide sequencing is now increasingly applied for tumor characterization, but not for g.MMR. The aim of this study was to evaluate the incidence and pathogenicity of g.MMR variants in Japanese cancer patients. METHODS: Four g.MMR genes (MLH1, MSH2, MSH6, and PMS2) were analyzed by next generation sequencing in 1058 cancer patients (614 male, 444 female; mean age 65.6 years) without past diagnosis of LS. The g.MMR variant pathogenicity was classified based on the ClinVar 2015 database. Tumor MMR immunohistochemistry, microsatellite instability (MSI), and BRAF sequencing were also investigated in specific cases. RESULTS: Overall, 46 g.MMR variants were detected in 167 (15.8%) patients, 17 likely benign variants in 119 patients, 24 variants of uncertain significance (VUSs) in 68 patients, two likely pathogenic variants in two patients, and three pathogenic variants in three (0.3%) patients. The three pathogenic variants included two colorectal cancers with MLH1 loss and high MSI and one endometrial cancer with MSH6 loss and microsatellite stability. Two likely pathogenic variants were shifted to VUSs by ClinVar (2018). One colon cancer with a likely benign variant demonstrated MLH1 loss and BRAF mutation, but other nonpathogenic variants showed sustained MMR and microsatellite stability. CONCLUSIONS: Universal sequencing of g.MMR genes demonstrated sundry benign variants, but only a small proportion of cancer patients had pathogenic variants. Pathogenicity evaluation using the ClinVar database agreed with MSI, MMR immunohistochemistry, and BRAF sequencing.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Proteínas de Ligação a DNA/genética , Mutação em Linhagem Germinativa , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Reparo de Erro de Pareamento de DNA , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Japão , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Análise de Sequência de DNA , Adulto Jovem
14.
Clin Radiol ; 74(10): 814.e21-814.e28, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31427042

RESUMO

AIM: To explore the role of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in evaluating DNA mismatch repair (MMR) status of rectal cancers preoperatively. MATERIALS AND METHODS: Seventy-six patients with a diagnosis of rectal cancer confirmed at endoscopic biopsy were enrolled prospectively and underwent IVIM MRI before surgery. RESULTS: The perfusion fraction (f) values of MMR proteins (MMRP) positive rectal cancers were significantly higher than negative cancers. The f values could differentiate MMRP positive rectal cancers from negative cancers with an area under the curve (AUC) of 0.695. The vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor 2 (VEGFR2) expression rates of positive MMRP rectal cancers were significantly higher than negative cancers. CONCLUSION: This pilot study indicated that the f value derived from IVIM MRI differed significantly between rectal cancers with different MMRP expression levels, which might be involved with different VEGF and VEGFR2 expression rates.


Assuntos
Reparo de Erro de Pareamento de DNA , Imagem por Ressonância Magnética/métodos , Neoplasias Retais/diagnóstico por imagem , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Ligação a DNA/metabolismo , Receptores ErbB/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Projetos Piloto , Estudos Prospectivos , Neoplasias Retais/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
15.
Int J Clin Oncol ; 24(9): 999-1011, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273487

RESUMO

Lynch syndrome is a cancer-predisposing syndrome inherited in an autosomal-dominant manner, wherein colon cancer and endometrial cancer develop frequently in the family, it results from a loss-of-function mutation in one of four different genes (MLH1, MSH2, MSH6, and PMS2) encoding mismatch repair proteins. Being located immediately upstream of the MSH2 gene, EPCAM abnormalities can affect MSH2 and cause Lynch syndrome. Mismatch repair proteins are involved in repairing of incorrect pairing (point mutations and deletion/insertion of simple repetitive sequences, so-called microsatellites) that can arise during DNA replication. MSH2 forms heterodimers with MSH6 or MSH3 (MutSα, MutSß, respectively) and is involved in mismatch-pair recognition and initiation of repair. MLH1 forms a complex with PMS2, and functions as an endonuclease. If the mismatch repair system is thoroughly working, genome integrity is maintained completely. Lynch syndrome is a state of mismatch repair deficiency due to a monoallelic abnormality of any mismatch repair genes. The phenotype indicating the mismatch repair deficiency can be frequently shown as a microsatellite instability in tumors. Children with germline biallelic mismatch repair gene abnormalities were reported to develop conditions such as gastrointestinal polyposis, colorectal cancer, brain cancer, leukemia, etc., and so on, demonstrating the need to respond with new concepts in genetic counseling. In promoting cancer genome medicine in a new era, such as by utilizing immune checkpoints, it is important to understand the genetic and genomic molecular background, including the status of mismatch repair deficiency.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA/fisiologia , Neoplasias Encefálicas/genética , Criança , Reparo de Erro de Pareamento de DNA/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Neoplasias do Endométrio/genética , Molécula de Adesão da Célula Epitelial/genética , Feminino , Aconselhamento Genético , Testes Genéticos , Humanos , Instabilidade de Microssatélites , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/genética , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/genética , Proteína 2 Homóloga a MutS/metabolismo , Mutação
16.
Cancer Commun (Lond) ; 39(1): 42, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31307542

RESUMO

BACKGROUND: The prevalence of Lynch syndrome and screening strategies for this disorder in Chinese patients with endometrial cancer have seldom been investigated. Such data would be essential for the screening, prevention, genetic counseling, and treatment of Lynch syndrome. The purpose of this prospective study was to determine the accuracy of the mismatch repair (MMR) protein immunohistochemistry (IHC), microsatellite instability (MSI) test, and clinical diagnostic criteria in screening for Lynch syndrome-associated endometrial cancer (LS-EC) in a prospective Chinese cohort. METHODS: All patients with newly diagnosed endometrial cancer (EC) were evaluated using clinical diagnostic criteria (Amsterdam II criteria and the revised Bethesda guidelines), MSI test, and IHC of MMR proteins in tumor tissues. For all patients, the screening results were compared with results of germline sequencing for pathogenic variants of MMR genes. RESULTS: Between December 2017 and August 2018, a total of 111 unselected patients with newly diagnosed EC were enrolled. Six patients (5.4%) harbored a pathogenic germline mutation of MMR genes: 1 had a mutation in MutL homolog 1 (MLH1), 2 in MutS homolog 2 (MSH2), and 3 in MutS homolog 6 (MSH6). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for identifying LS-EC were 33.3%, 88.6%, 14.3%, and 95.9%, for the clinical criteria, 66.7%, 75.0%, 14.3%, and 97.3% for IHC of MMR proteins, 100%, 89.9%, 33.3%, and 100% for MSI test, and 100%, 72.4%, 20.0% and 100% for combined IHC and MSI test, respectively. The combination of IHC and MSI test had higher sensitivity and PPV than the clinical criteria (p = 0.030). MSI test and IHC were highly concordant for LS-EC screening (73/77, 94.8%). CONCLUSION: The accuracy of the combination of IHC of MMR proteins and MSI test for screening LS among Chinese patients with EC was superior to that of the clinical criteria. Trial registration NCT03291106. Registered on September 25, 2017.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Detecção Precoce de Câncer/métodos , Neoplasias do Endométrio/diagnóstico , Programas de Rastreamento/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Neoplasias Colorretais Hereditárias sem Polipose/complicações , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Reparo de Erro de Pareamento de DNA , Proteínas de Ligação a DNA/metabolismo , Neoplasias do Endométrio/etiologia , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/metabolismo , Feminino , Mutação em Linhagem Germinativa , Humanos , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , Estudos Prospectivos
17.
Genet Med ; 21(12): 2706-2712, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31204389

RESUMO

PURPOSE: Biallelic pathogenic variants in the mismatch repair (MMR) genes cause a recessive childhood cancer predisposition syndrome known as constitutional mismatch repair deficiency (CMMRD). Family members with a heterozygous MMR variant have Lynch syndrome. We aimed at estimating cancer risk in these heterozygous carriers as a novel approach to avoid complicated statistical methods to correct for ascertainment bias. METHODS: Cumulative colorectal cancer incidence was estimated in a cohort of PMS2- and MSH6-associated families, ascertained by the CMMRD phenotype of the index, by using mutation probabilities based on kinship coefficients as analytical weights in a proportional hazard regression on the cause-specific hazards. Confidence intervals (CIs) were obtained by bootstrapping at the family level. RESULTS: The estimated cumulative colorectal cancer risk at age 70 years for heterozygous PMS2 variant carriers was 8.7% (95% CI 4.3-12.7%) for both sexes combined, and 9.9% (95% CI 4.9-15.3%) for men and 5.9% (95% CI 1.6-11.1%) for women separately. For heterozygous MSH6 variant carriers these estimates are 11.8% (95% CI 4.5-22.7%) for both sexes combined, 10.0% (95% CI 1.83-24.5%) for men and 11.7% (95% CI 2.10-26.5%) for women. CONCLUSION: Our findings are consistent with previous reports that used more complex statistical methods to correct for ascertainment bias. These results underline the need for MMR gene-specific surveillance protocols for Lynch syndrome.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/complicações , Neoplasias Colorretais/etiologia , Medição de Risco/métodos , Adulto , Idoso , Estudos de Coortes , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Reparo de Erro de Pareamento de DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Mutação , Fatores de Risco
18.
Hum Mutat ; 40(7): 904-907, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30946512

RESUMO

PMS2 is one of the four susceptibility genes in Lynch syndrome (LS), the most common cancer syndrome in the world. Inherited mutations in DNA mismatch repair (MMR) genes, MLH1, MSH2, and MSH6, account for approximately 90% of LS, while a relatively small number of LS families segregate a PMS2 mutation. This and the low cancer penetrance in PMS2 families suggest that PMS2 is only a moderate or low-risk susceptibility gene. We have previously shown that even a partial expression decrease in MLH1, MSH2, or MSH6 suggests that heterozygous LS mutation carriers have MMR malfunction in constitutive tissues. Whether and how PMS2 expression decrease affects the repair capability is not known. Here, we show that PMS2 knockdown cells retaining 19%, 33%, or 53% of PMS2 expression all have significantly reduced MMR efficiency. Surprisingly, the cells retaining expression levels comparable to PMS2 mutation carriers indicate the lowest repair efficiency.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Regulação para Baixo , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Reparo de Erro de Pareamento de DNA , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Predisposição Genética para Doença , Células HCT116 , Humanos , Mutação
19.
Gynecol Oncol ; 153(3): 487-495, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30922603

RESUMO

OBJECTIVE: Approximately 15% of endometrial carcinomas (ECs) arise in young women who may wish to avoid surgical menopause and/or preserve fertility. Our aim was to evaluate the prognostic significance of Proactive Molecular risk classifier for Endometrial Carcinoma (ProMisE) in young (<50 yo) women with EC. METHODS: ProMisE was applied to a retrospective cohort of women with ECs <50 yo at diagnosis, and associations between the four ProMisE molecular subtypes (MMR deficient (MMRd), POLE mutated (POLE), p53 wild type (p53wt), and p53 abnormal (p53abn)) and clinicopathological parameters, including outcomes, were assessed. RESULTS: Of 257 ECs, there were 48 (19%) MMRd, 34 (13%) POLE, 164 (64%) p53wt and 11 (4%) p53abn. ProMisE subtypes were associated with differences in all measured clinicopathological parameters except for presence of synchronous ovarian tumours and fertility. Age at diagnosis was youngest and BMI highest in women with p53wt ECs. MMRd and p53abn tumours were more likely to be advanced stage (III/IV), high-risk (ESMO), and receive chemotherapy. ProMisE subtypes were strongly associated with outcomes (overall, disease-specific, and progression-free survival (p < 0.0001 for all)). Advanced stage, grade, LVSI, myometrial invasion and ESMO risk groups showed associations with some but not all survival parameters. ProMisE maintained a strong association with OS and DSS on multivariable analysis. CONCLUSIONS: ProMisE molecular classification is prognostic in young women with EC, enabling early stratification and risk assignment to direct care. Further studies can assess response to therapy, fertility, and cancer-related outcomes within the framework of molecular subtype.


Assuntos
Carcinoma/classificação , DNA Polimerase II/genética , Proteínas de Ligação a DNA/metabolismo , Neoplasias do Endométrio/classificação , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/genética , Proteína Supressora de Tumor p53/metabolismo , Adulto , Fatores Etários , Índice de Massa Corporal , Carcinoma/genética , Carcinoma/metabolismo , Carcinoma/secundário , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/metabolismo , Neoplasias do Endométrio/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , Intervalo Livre de Progressão , Estudos Retrospectivos , Taxa de Sobrevida
20.
Int J Cancer ; 145(3): 705-713, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30693488

RESUMO

Early-onset (<50 years-old) nonpolyposis nonfamilial colorectal cancer (EO NP NF CRC) is a common clinical challenge. Although Lynch syndrome (LS) is associated with EO CRC, the frequency of this syndrome in the EO NF cases remains unknown. Besides, mismatch repair deficient (MMRd) CRCs with negative MMR gene testing have recently been described in up to 60% of cases and termed "Lynch-like syndrome" (LLS). Management and counseling decisions of these patients are complicated because of unconfirmed suspicions of hereditary cancer. To define the prevalence of MMR deficient CRCs, LS and LLS in patients with EO NP NF CRC, we recruited 102 patients with a first diagnosis of NP NF CRC ≤ 50 years old during 2003-2009 who underwent genetic counseling at our institution in Argentina. Tumor immunohistochemical (IHC) MMR for protein expression and microsatellite instability (MSI) status were evaluated, and in those with loss of MLH1 expression by IHC, somatic BRAF V600E mutation and both somatic and germline MLH1 methylation levels were studied. Tumors characterized as MMRd without somatic BRAF mutation nor MLH1 methylation were sent for germline analysis. Twenty one (20.6%) tumors were MMRd. Fourteen of 16 putative LS cases underwent germline testing: 6 pathogenic mutations were identified and 8 cases had no identifiable pathogenic mutations. The prevalence of LS and LLS in this cohort was 5.8% (6/102) and 7.8% (8/102), respectively. As a conclusion we found that 20% of patients with EO NP NF CRC have MMRd tumors, and at least half of these are likely to have LLS.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Adolescente , Adulto , Criança , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Enzimas Reparadoras do DNA/deficiência , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Feminino , Mutação em Linhagem Germinativa , Humanos , Imuno-Histoquímica , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Proteína 1 Homóloga a MutL/genética , Proteína 1 Homóloga a MutL/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Estudos Retrospectivos , Adulto Jovem
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