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1.
Eur J Hum Genet ; 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31616036

RESUMO

Germline variants in the DNA mismatch repair (MMR) gene PMS2 cause 1-14% of all Lynch Syndrome cancers. Correct variant analysis of PMS2 is complex due to the presence of multiple pseudogenes and the occurrence of gene conversion. The analysis complexity increases in highly fragmented DNA from formalin-fixed paraffin-embedded (FFPE) tissue. Here we describe a reliable approach to detect true PMS2 variants in fragmented DNA. A custom NGS panel designed for FFPE tissue was used targeting four MMR genes, POLE and POLD1. Amplicon design for PMS2 was based on the position of paralogous sequence variants (PSVs) that distinguish PMS2 from its pseudogenes. PMS2 variants in exons 1-11 can be correctly curated based on this information. For exons 12-15 this is less reliable as these undergo gene conversion. Using this method, we screened PMS2 variants in 125 MMR-deficient tumors. Of the 125 tumors tested, six were unexplained MMR-deficient tumors with solitary PMS2 protein expression loss. In these six tumors two unclassified variants (class 3) and five variants likely affecting function (class 4/5) were detected in PMS2. One microsatellite unstable tumor with positive staining for all MMR proteins was found to carry a frameshift PMS2 variant (class 5). No class 4 or class 5 PMS2 variants were detected in tumors with other patterns of MMR protein expression loss.

2.
J Clin Oncol ; 36(29): 2961-2968, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30161022

RESUMO

PURPOSE: Lynch syndrome due to pathogenic variants in the DNA mismatch repair genes MLH1, MSH2, and MSH6 is predominantly associated with colorectal and endometrial cancer, although extracolonic cancers have been described within the Lynch tumor spectrum. However, the age-specific cumulative risk (penetrance) of these cancers is still poorly defined for PMS2-associated Lynch syndrome. Using a large data set from a worldwide collaboration, our aim was to determine accurate penetrance measures of cancers for carriers of heterozygous pathogenic PMS2 variants. METHODS: A modified segregation analysis was conducted that incorporated both genotyped and nongenotyped relatives, with conditioning for ascertainment to estimates corrected for bias. Hazard ratios (HRs) and corresponding 95% CIs were estimated for each cancer site for mutation carriers compared with the general population, followed by estimation of penetrance. RESULTS: In total, 284 families consisting of 4,878 first- and second-degree family members were included in the analysis. PMS2 mutation carriers were at increased risk for colorectal cancer (cumulative risk to age 80 years of 13% [95% CI, 7.9% to 22%] for males and 12% [95% CI, 6.7% to 21%] for females) and endometrial cancer (13% [95% CI, 7.0%-24%]), compared with the general population (6.6%, 4.7%, and 2.4%, respectively). There was no clear evidence of an increased risk of ovarian, gastric, hepatobiliary, bladder, renal, brain, breast, prostate, or small bowel cancer. CONCLUSION: Heterozygous PMS2 mutation carriers were at small increased risk for colorectal and endometrial cancer but not for any other Lynch syndrome-associated cancer. This finding justifies that PMS2-specific screening protocols could be restricted to colonoscopies. The role of risk-reducing hysterectomy and bilateral salpingo-oophorectomy for PMS2 mutation carriers needs further discussion.

3.
J Mol Diagn ; 20(5): 600-611, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29936257

RESUMO

BRCA1/2 variant analysis in tumor tissue could streamline the referral of patients with epithelial ovarian, fallopian tube, or primary peritoneal cancer to genetic counselors and select patients who benefit most from targeted treatment. We investigated the sensitivity of BRCA1/2 variant analysis in formalin-fixed, paraffin-embedded tumor tissue using a combination of next-generation sequencing and copy number variant multiplex ligation-dependent probe amplification. After optimization using a training cohort of known BRCA1/2 mutation carriers, validation was performed in a prospective cohort in which screening of BRCA1/2 tumor DNA and leukocyte germline DNA was performed in parallel. BRCA1 promoter hypermethylation and pedigree analysis were also performed. In the training cohort, 45 of 46 germline BRCA1/2 variants were detected (sensitivity, 98%). In the prospective cohort (n = 62), all six germline variants were identified (sensitivity, 100%), together with five somatic BRCA1/2 variants and eight cases with BRCA1 promoter hypermethylation. In four BRCA1/2 variant-negative patients, surveillance or prophylactic management options were offered on the basis of positive family histories. We conclude that BRCA1/2 formalin-fixed, paraffin-embedded tumor tissue analysis reliably detects BRCA1/2 variants. When taking family history of BRCA1/2 variant-negative patients into account, tumor BRCA1/2 variant screening allows more efficient selection of epithelial ovarian cancer patients for genetic counseling and simultaneously selects patients who benefit most from targeted treatment.

4.
Eur J Hum Genet ; 26(8): 1143-1150, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29706640

RESUMO

High-throughput sequencing efforts in molecular tumour diagnostics detect increasing numbers of novel variants, including variants predicted to affect splicing. In silico prediction tools can reliably predict the effect of variant disrupting canonical splice sites; however, experimental validation is required to confirm aberrant splicing. Here, we present RNA analysis performed for 13 canonical splice site variants predicted or known to result in splicing in the cancer predisposition genes MLH1, MSH2, MSH6, APC and BRCA1. Total nucleic acid was successfully isolated for 10 variants from eight formalin-fixed paraffin-embedded (FFPE) tumour tissues and two B-cell lines. Aberrant splicing was confirmed in all six variants known to result in splicing. Of one known variant in the B-cell line, aberrant splicing could only be detected after formalin fixation, which indicated that formalin fixation could possibly inhibit RNA degradation. Aberrant splicing was concluded in three of four predicted splice variants of uncertain significance, supporting their pathogenic effect. With this assay, somatic splice variants can be easily and rapidly analysed, enabling retrospective analysis to support the pathogenicity of variants predicted to result in splicing when only FFPE material is available.

6.
Fam Cancer ; 17(4): 507-515, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29147930

RESUMO

Lynch syndrome (LS) patients are at high risk of developing colorectal cancer (CRC). Phenotypic variability might in part be explained by common susceptibility loci identified in Genome Wide Association Studies (GWAS). Previous studies focused mostly on MLH1, MSH2 and MSH6 carriers, with conflicting results. We aimed to determine the role of GWAS SNPs in PMS2 mutation carriers. A cohort study was performed in 507 PMS2 carriers (124 CRC cases), genotyped for 24 GWAS SNPs, including SNPs at 11q23.1 and 8q23.3. Hazard ratios (HRs) were calculated using a weighted Cox regression analysis to correct for ascertainment bias. Discrimination was assessed with a concordance statistic in a bootstrap cross-validation procedure. Individual SNPs only had non-significant associations with CRC occurrence with HRs lower than 2, although male carriers of allele A at rs1321311 (6p21.31) may have increased risk of CRC (HR = 2.1, 95% CI 1.2-3.0). A polygenic risk score (PRS) based on 24 HRs had an HR of 2.6 (95% CI 1.5-4.6) for the highest compared to the lowest quartile, but had no discriminative ability (c statistic 0.52). Previously suggested SNPs do not modify CRC risk in PMS2 carriers. Future large studies are needed for improved risk stratification among Lynch syndrome patients.

7.
Fam Cancer ; 17(3): 415-420, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29124495

RESUMO

Patients synchronously or metachronously presenting with ovarian and colon cancer can pose diagnostic challenges. A primary colon carcinoma can metastasize to one or both ovaries, two independent primary tumors can arise or an ovarian carcinoma can metastasize to the colon. Clinical and immunohistochemical characterization can aid the diagnosis. Recently, we reported that in difficult cases finding pathogenic APC variants supports a colonic origin.In this case report we describe the clinical history of a female patient suspected for Lynch syndrome. She was diagnosed with a bilateral ovarian cancer at age 44, followed by the detection of a colon carcinoma 12.5 months later. Lesions of both sites showed a DNA mismatch repair deficiency with immunohistochemical loss of MLH1 and PMS2 expression without MLH1 promoter hypermethylation. In absence of germline MMR gene variants identical somatic MLH1 and CTNNB1 gene variants were found, indicating a clonal relation. MMR germline mosaicism was made unlikely by ultra deep sequencing of the MLH1 variant in DNA isolated from normal mucosa, blood, urine and saliva. Although initially being suspect for Lynch syndrome it was eventually concluded that a metachronously diagnosed colon carcinoma that metastasized to both ovaries was most likely.

8.
Gut ; 67(7): 1306-1316, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-28754778

RESUMO

BACKGROUND: Most patients with path_MMR gene variants (Lynch syndrome (LS)) now survive both their first and subsequent cancers, resulting in a growing number of older patients with LS for whom limited information exists with respect to cancer risk and survival. OBJECTIVE AND DESIGN: This observational, international, multicentre study aimed to determine prospectively observed incidences of cancers and survival in path_MMR carriers up to 75 years of age. RESULTS: 3119 patients were followed for a total of 24 475 years. Cumulative incidences at 75 years (risks) for colorectal cancer were 46%, 43% and 15% in path_MLH1, path_MSH2 and path_MSH6 carriers; for endometrial cancer 43%, 57% and 46%; for ovarian cancer 10%, 17% and 13%; for upper gastrointestinal (gastric, duodenal, bile duct or pancreatic) cancers 21%, 10% and 7%; for urinary tract cancers 8%, 25% and 11%; for prostate cancer 17%, 32% and 18%; and for brain tumours 1%, 5% and 1%, respectively. Ovarian cancer occurred mainly premenopausally. By contrast, upper gastrointestinal, urinary tract and prostate cancers occurred predominantly at older ages. Overall 5-year survival for prostate cancer was 100%, urinary bladder 93%, ureter 85%, duodenum 67%, stomach 61%, bile duct 29%, brain 22% and pancreas 0%. Path_PMS2 carriers had lower risk for cancer. CONCLUSION: Carriers of different path_MMR variants exhibit distinct patterns of cancer risk and survival as they age. Risk estimates for counselling and planning of surveillance and treatment should be tailored to each patient's age, gender and path_MMR variant. We have updated our open-access website www.lscarisk.org to facilitate this.


Assuntos
Neoplasias do Colo/epidemiologia , Neoplasias Colorretais Hereditárias sem Polipose/complicações , Neoplasias Colorretais Hereditárias sem Polipose/mortalidade , Neoplasias Pancreáticas/epidemiologia , Neoplasias Urogenitais/epidemiologia , Fatores Etários , Idoso , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Bases de Dados Factuais , Feminino , Humanos , Incidência , Masculino , Estudos Prospectivos
9.
Br J Cancer ; 117(6): 1215-1223, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28742792

RESUMO

BACKGROUND: A substantial fraction of familial colorectal cancer (CRC) and polyposis heritability remains unexplained. This study aimed to identify predisposing loci in patients with these disorders. METHODS: Homozygosity mapping was performed using 222 563 SNPs in 302 index patients with various colorectal neoplasms and 3367 controls. Linkage analysis, exome and whole-genome sequencing were performed in a family affected by microsatellite stable CRCs. Candidate variants were genotyped in 10 554 cases and 21 480 controls. Gene expression was assessed at the mRNA and protein level. RESULTS: Homozygosity mapping revealed a disease-associated region at 1q32.3 which was part of the linkage region 1q32.2-42.2 identified in the CRC family. This includes a region previously associated with risk of CRC. Sequencing identified the p.Asp1432Glu variant in the MIA3 gene (known as TANGO1 or TANGO) and 472 additional rare, shared variants within the linkage region. In both cases and controls the population frequency was 0.02% for this MIA3 variant. The MIA3 mutant allele showed predominant mRNA expression in normal, cancer and precancerous tissues. Furthermore, immunohistochemistry revealed increased expression of MIA3 in adenomatous tissues. CONCLUSIONS: Taken together, our two independent strategies associate genetic variations in chromosome 1q loci and predisposition to familial CRC and polyps, which warrants further investigation.


Assuntos
Polipose Adenomatosa do Colo/genética , Translocador Nuclear Receptor Aril Hidrocarboneto/genética , Cromossomos Humanos Par 1/genética , Neoplasias Colorretais/genética , Predisposição Genética para Doença , Proteínas de Neoplasias/genética , Translocador Nuclear Receptor Aril Hidrocarboneto/metabolismo , Mapeamento Cromossômico , Proteínas Ativadoras de GTPase/genética , Proteínas Ativadoras de GTPase/metabolismo , Ligação Genética , Genótipo , Homozigoto , Humanos , Repetições de Microssatélites , Proteínas de Neoplasias/metabolismo , Polimorfismo de Nucleotídeo Único , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/metabolismo , RNA Mensageiro/metabolismo
10.
Gastroenterology ; 152(3): 546-549.e3, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27816598

RESUMO

We investigated the presence and patterns of mosaicism in the APC gene in patients with colon neoplasms not associated with any other genetic variants; we performed deep sequence analysis of APC in at least 2 adenomas or carcinomas per patient. We identified mosaic variants in APC in adenomas from 9 of the 18 patients with 21 to approximately 100 adenomas. Mosaic variants of APC were variably detected in leukocyte DNA and/or non-neoplastic intestinal mucosa of these patients. In a comprehensive sequence analysis of 1 patient, we found no evidence for mosaicism in APC in non-neoplastic intestinal mucosa. One patient was found to carry a mosaic c.4666dupA APC variant in only 10 of 16 adenomas, indicating the importance of screening 2 or more adenomas for genetic variants.


Assuntos
Adenoma/genética , Polipose Adenomatosa do Colo/genética , Carcinoma/genética , Neoplasias Colorretais/genética , Genes APC , Mosaicismo , Neoplasias Primárias Múltiplas/genética , Adulto , Idoso , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sequência de DNA , Via de Sinalização Wnt
11.
Hum Mutat ; 37(11): 1162-1179, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27435373

RESUMO

Monoallelic PMS2 germline mutations cause 5%-15% of Lynch syndrome, a midlife cancer predisposition, whereas biallelic PMS2 mutations cause approximately 60% of constitutional mismatch repair deficiency (CMMRD), a rare childhood cancer syndrome. Recently improved DNA- and RNA-based strategies are applied to overcome problematic PMS2 mutation analysis due to the presence of pseudogenes and frequent gene conversion events. Here, we determined PMS2 mutation detection yield and mutation spectrum in a nationwide cohort of 396 probands. Furthermore, we studied concordance between tumor IHC/MSI (immunohistochemistry/microsatellite instability) profile and mutation carrier state. Overall, we found 52 different pathogenic PMS2 variants explaining 121 Lynch syndrome and nine CMMRD patients. In vitro mismatch repair assays suggested pathogenicity for three missense variants. Ninety-one PMS2 mutation carriers (70%) showed isolated loss of PMS2 in their tumors, for 31 (24%) no or inconclusive IHC was available, and eight carriers (6%) showed discordant IHC (presence of PMS2 or loss of both MLH1 and PMS2). Ten cases with isolated PMS2 loss (10%; 10/97) harbored MLH1 mutations. We confirmed that recently improved mutation analysis provides a high yield of PMS2 mutations in patients with isolated loss of PMS2 expression. Application of universal tumor prescreening methods will however miss some PMS2 germline mutation carriers.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais/genética , Análise Mutacional de DNA/métodos , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Síndromes Neoplásicas Hereditárias/genética , Neoplasias Encefálicas/metabolismo , Estudos de Coortes , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Predisposição Genética para Doença , Variação Genética , Mutação em Linhagem Germinativa , Humanos , Instabilidade de Microssatélites , Endonuclease PMS2 de Reparo de Erro de Pareamento/metabolismo , Síndromes Neoplásicas Hereditárias/metabolismo , Países Baixos
12.
PLoS One ; 11(6): e0157381, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27300758

RESUMO

BACKGROUND AND AIMS: Lynch Syndrome (LS) is caused by pathogenic germline variants in one of the mismatch repair (MMR) genes. However, up to 60% of MMR-deficient colorectal cancer cases are categorized as suspected Lynch Syndrome (sLS) because no pathogenic MMR germline variant can be identified, which leads to difficulties in clinical management. We therefore analyzed the genomic regions of 15 CRC susceptibility genes in leukocyte DNA of 34 unrelated sLS patients and 11 patients with MLH1 hypermethylated tumors with a clear family history. METHODS: Using targeted next-generation sequencing, we analyzed the entire non-repetitive genomic sequence, including intronic and regulatory sequences, of 15 CRC susceptibility genes. In addition, tumor DNA from 28 sLS patients was analyzed for somatic MMR variants. RESULTS: Of 1979 germline variants found in the leukocyte DNA of 34 sLS patients, one was a pathogenic variant (MLH1 c.1667+1delG). Leukocyte DNA of 11 patients with MLH1 hypermethylated tumors was negative for pathogenic germline variants in the tested CRC susceptibility genes and for germline MLH1 hypermethylation. Somatic DNA analysis of 28 sLS tumors identified eight (29%) cases with two pathogenic somatic variants, one with a VUS predicted to pathogenic and LOH, and nine cases (32%) with one pathogenic somatic variant (n = 8) or one VUS predicted to be pathogenic (n = 1). CONCLUSIONS: This is the first study in sLS patients to include the entire genomic sequence of CRC susceptibility genes. An underlying somatic or germline MMR gene defect was identified in ten of 34 sLS patients (29%). In the remaining sLS patients, the underlying genetic defect explaining the MMRdeficiency in their tumors might be found outside the genomic regions harboring the MMR and other known CRC susceptibility genes.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais/genética , Metilação de DNA , Reparo de Erro de Pareamento de DNA , Regulação Neoplásica da Expressão Gênica , Estudos de Coortes , Colo/metabolismo , Colo/patologia , Neoplasias Colorretais/patologia , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Mutação em Linhagem Germinativa , Humanos , Leucócitos/metabolismo , Leucócitos/patologia , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL/genética , Reto/metabolismo , Reto/patologia
13.
Fam Cancer ; 15(3): 429-35, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26973060

RESUMO

The Dutch Hereditary Cancer Registry was established in 1985 with the support of the Ministry of Health (VWS). The aims of the registry are: (1) to promote the identification of families with hereditary cancer, (2) to encourage the participation in surveillance programs of individuals at high risk, (3) to ensure the continuity of lifelong surveillance examinations, and (4) to promote research, in particular the improvement of surveillance protocols. During its early days the registry provided assistance with family investigations and the collection of medical data, and recommended surveillance when a family fulfilled specific diagnostic criteria. Since 2000 the registry has focused on family follow-up, and ensuring the quality of surveillance programs and appropriate clinical management. Since its founding, the registry has identified over 10,000 high-risk individuals with a diverse array of hereditary cancer syndromes. All were encouraged to participate in prevention programmes. The registry has published a number of studies that evaluated the outcome of surveillance protocols for colorectal cancer (CRC) in Lynch syndrome, as well as in familial colorectal cancer. In 2006, evaluation of the effect of registration and colonoscopic surveillance on the mortality rate associated with colorectal cancer (CRC) showed that the policy led to a substantial decrease in the mortality rate associated with CRC. Following discovery of MMR gene defects, the first predictive model that could select families for genetic testing was published by the Leiden group. In addition, over the years the registry has produced many cancer risk studies that have helped to develop appropriate surveillance protocols. Hereditary cancer registries in general, and the Lynch syndrome registry in particular, play an important role in improving the clinical management of affected families.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Detecção Precoce de Câncer/métodos , Predisposição Genética para Doença , Testes Genéticos/métodos , Sistema de Registros , Colonoscopia , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Reparo de Erro de Pareamento de DNA/genética , Enzimas Reparadoras do DNA/genética , Humanos , Incidência , Metanálise como Assunto , Mutação , Países Baixos/epidemiologia
14.
Eur J Hum Genet ; 24(7): 1089-92, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26648449

RESUMO

Many suspected Lynch Syndrome (sLS) patients who lack mismatch repair (MMR) germline gene variants and MLH1 or MSH2 hypermethylation are currently explained by somatic MMR gene variants or, occasionally, by germline POLE variants. To further investigate unexplained sLS patients, we analyzed leukocyte and tumor DNA of 62 sLS patients using gene panel sequencing including the POLE, POLD1 and MMR genes. Forty tumors showed either one, two or more somatic MMR variants predicted to affect function. Nine sLS tumors showed a likely ultramutated phenotype and were found to carry germline (n=2) or somatic variants (n=7) in the POLE/POLD1 exonuclease domain (EDM). Six of these POLE/POLD1-EDM mutated tumors also carried somatic MMR variants. Our findings suggest that faulty proofreading may result in loss of MMR and thereby in microsatellite instability.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA , DNA Polimerase III/genética , DNA Polimerase II/genética , Adulto , Idoso , Domínio Catalítico , Evolução Clonal , Neoplasias Colorretais Hereditárias sem Polipose/patologia , DNA Polimerase II/química , DNA Polimerase III/química , Feminino , Instabilidade Genômica , Mutação em Linhagem Germinativa , Humanos , Masculino , Repetições de Microssatélites , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Proteínas de Ligação a Poli-ADP-Ribose
15.
Genet Med ; 18(4): 405-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26110232

RESUMO

PURPOSE: Lynch syndrome (LS), a heritable disorder with an increased risk of primarily colorectal cancer (CRC) and endometrial cancer (EC), can be caused by mutations in the PMS2 gene. We wished to establish whether genotype and/or parent-of-origin effects (POE) explain (part of) the reported variability in severity of the phenotype. METHODS: European PMS2 mutation carriers (n = 381) were grouped and compared based on RNA expression and whether the mutation was inherited paternally or maternally. RESULTS: Mutation carriers with loss of RNA expression (group 1) had a significantly lower age at CRC diagnosis (51.1 years vs. 60.0 years, P = 0.035) and a lower age at EC diagnosis (55.8 years vs. 61.0 years, P = 0.2, nonsignificant) compared with group 2 (retention of RNA expression). Furthermore, group 1 showed slightly higher, but nonsignificant, hazard ratios (HRs) for both CRC (HR: 1.31, P = 0.38) and EC (HR: 1.22, P = 0.72). No evidence for a significant parent-of-origin effect was found for either CRC or EC. CONCLUSIONS: PMS2 mutation carriers with retention of RNA expression developed CRC 9 years later than those with loss of RNA expression. If confirmed, this finding would justify a delay in surveillance for these cases. Cancer risk was not influenced by a parent-of-origin effect.Genet Med 18 4, 405-409.


Assuntos
Heterozigoto , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Mutação , Neoplasias/genética , Adulto , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Expressão Gênica , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Mutação em Linhagem Germinativa , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Risco
16.
Mol Genet Genomic Med ; 3(4): 327-45, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26247049

RESUMO

A subset of DNA variants causes genetic disease through aberrant splicing. Experimental splicing assays, either RT-PCR analyses of patient RNA or functional splicing reporter minigene assays, are required to evaluate the molecular nature of the splice defect. Here, we present minigene assays performed for 17 variants in the consensus splice site regions, 14 exonic variants outside these regions, and two deep intronic variants, all in the DNA mismatch-repair (MMR) genes MLH1, MSH2, MSH6, and PMS2, associated with Lynch syndrome. We also included two deep intronic variants in APC and PKD2. For one variant (MLH1 c.122A>G), our minigene assay and patient RNA analysis could not confirm the previously reported aberrant splicing. The aim of our study was to further investigate the concordance between minigene splicing assays and patient RNA analyses. For 30 variants results from patient RNA analyses were available, either performed by our laboratory or presented in literature. Some variants were deliberately included in this study because they resulted in multiple aberrant transcripts in patient RNA analysis, or caused a splice effect other than the prevalent exon skip. While both methods were completely concordant in the assessment of splice effects, four variants exhibited major differences in aberrant splice patterns. Based on the present and earlier studies, together showing an almost 100% concordance of minigene assays with patient RNA analyses, we discuss the weight given to minigene splicing assays in the current criteria proposed by InSiGHT for clinical classification of MMR variants.

17.
Eur J Hum Genet ; 23(8): 1080-4, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25370038

RESUMO

Germline variants affecting the exonuclease domains of POLE and POLD1 predispose to multiple colorectal adenomas and/or colorectal cancer (CRC). The aim of this study was to estimate the prevalence of previously described heterozygous germline variants POLE c.1270C>G, p.(Leu424Val) and POLD1 c.1433G>A, p.(Ser478Asn) in a Dutch series of unexplained familial, early onset CRC and polyposis index cases. We examined 1188 familial CRC and polyposis index patients for POLE p.(Leu424Val) and POLD1 p.(Ser478Asn) variants using competitive allele-specific PCR. In addition, protein expression of the POLE and DNA mismatch repair genes was studied by immunohistochemistry in tumours from POLE carriers. Somatic mutations were screened using semiconductor sequencing. We detected three index patients (0.25%) with a POLE p.(Leu424Val) variant. In one patient, the variant was found to be de-novo. Tumours from three patients from two families were microsatellite instable, and immunohistochemistry showed MSH6/MSH2 deficiency suggestive of Lynch syndrome. Somatic mutations but no germline MSH6 and MSH2 variants were subsequently found, and one tumour displayed a hypermutator phenotype. None of the 1188 patients carried the POLD1 p.(Ser478Asn) variant. POLE germline variant carriers are also associated with a microsatellite instable CRC. POLE DNA analysis now seems warranted in microsatellite instable CRC, especially in the absence of a causative DNA mismatch repair gene germline variant.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Colorretais/genética , DNA Polimerase III/genética , DNA Polimerase II/genética , Síndromes Neoplásicas Hereditárias/genética , Adolescente , Adulto , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/patologia , Neoplasias Colorretais/complicações , Neoplasias Colorretais/patologia , Reparo de Erro de Pareamento de DNA , Proteínas de Ligação a DNA/genética , Feminino , Mutação em Linhagem Germinativa , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 2 Homóloga a MutS/genética , Síndromes Neoplásicas Hereditárias/complicações , Síndromes Neoplásicas Hereditárias/patologia , Proteínas de Ligação a Poli-ADP-Ribose
18.
Biol Blood Marrow Transplant ; 21(3): 473-82, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25485863

RESUMO

The outcome of allogeneic hematopoietic stem cell transplantation (HSCT) is strongly affected by the kinetics of reconstitution of the immune system. This study compared the effects of antithymocyte globulin (ATG) and alemtuzumab on various outcome parameters after HSCT. The study cohort consisted of 148 children, with a median age of 9.6 years (range, .4 to 19.0), who underwent HSCT for malignant and benign hematological disorders in a single HSCT unit. Conditioning included ATG (n = 110) or alemtuzumab (n = 38). Cox proportional hazard regression analysis showed that alemtuzumab significantly delayed the recovery of CD3(+) T cells and CD4(+)as well as CD8(+) T cell subsets (P ≤ .001) and natural killer (NK) cells (P = .008) compared with ATG. In both ATG- and alemtuzumab-treated patients, shorter drug exposure lead to significantly faster recovery of T cells. Alemtuzumab was associated with lower donor chimerism 3 and 6 months after transplantation and a higher risk of disease relapse (P = .001). The overall survival and event-free survival risks were significantly lower for alemtuzumab-treated patients (P = .020 and P < .001, respectively). Patients who received alemtuzumab showed a trend to lower risk of acute graft-versus-host disease, more human adenovirus, and less Epstein-Barr virus reactivations compared with patients who received ATG. These data indicate that children treated with alemtuzumab as part of the conditioning regimen have a slower T cell and NK cell reconstitution compared with those treated with ATG, which compromises the overall and event-free survival. Prolonged length of lympholytic drug exposure delayed the T cell recovery in both ATG- and alemtuzumab-treated patients. Therefore, we recommend detailed pharmacokinetic/pharmacodynamic (PK/PD) analyses in a larger cohort of patients to develop an algorithm aiming at optimization of the serotherapy containing conditioning regimen.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Soro Antilinfocitário/administração & dosagem , Antineoplásicos/administração & dosagem , Transplante de Células-Tronco Hematopoéticas , Recuperação de Função Fisiológica , Condicionamento Pré-Transplante , Adolescente , Adulto , Alemtuzumab , Aloenxertos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Neoplasias Hematológicas/imunologia , Neoplasias Hematológicas/mortalidade , Neoplasias Hematológicas/terapia , Humanos , Lactente , Masculino , Recuperação de Função Fisiológica/efeitos dos fármacos , Recuperação de Função Fisiológica/imunologia , Estudos Retrospectivos , Taxa de Sobrevida
19.
J Clin Oncol ; 33(4): 319-25, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25512458

RESUMO

PURPOSE: The clinical consequences of PMS2 germline mutations are poorly understood compared with other Lynch-associated mismatch repair gene (MMR) mutations. The aim of this European cohort study was to define the cancer risk faced by PMS2 mutation carriers. METHODS: Data were collected from 98 PMS2 families ascertained from family cancer clinics that included a total of 2,548 family members and 377 proven mutation carriers. To adjust for potential ascertainment bias, a modified segregation analysis model was used to calculate colorectal cancer (CRC) and endometrial cancer (EC) risks. Standardized incidence ratios (SIRs) were calculated to estimate risks for other Lynch syndrome-associated cancers. RESULTS: The cumulative risk (CR) of CRC for male mutation carriers by age 70 years was 19%. The CR among female carriers was 11% for CRC and 12% for EC. The mean age of CRC development was 52 years, and there was a significant difference in mean age of CRC between the probands (mean, 47 years; range, 26 to 68 years) and other family members with a PMS2 mutation (mean, 58 years; range, 31 to 86 years; P < .001). Significant SIRs were observed for cancers of the small bowel, ovaries, breast, and renal pelvis. CONCLUSION: CRC and EC risks were found to be markedly lower than those previously reported for the other MMR. However, these risks embody the isolated risk of carrying a PMS2 mutation, and it should be noted that we observed a substantial variation in cancer phenotype within and between families, suggesting the influence of genetic modifiers and lifestyle factors on cancer risks.


Assuntos
Adenosina Trifosfatases/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Enzimas Reparadoras do DNA/genética , Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Neoplasias Colorretais/genética , Análise Mutacional de DNA , Neoplasias do Endométrio/genética , Saúde da Família , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento , Fatores de Risco
20.
J Exp Clin Cancer Res ; 33: 27, 2014 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-24612598

RESUMO

BACKGROUND: In osteosarcoma, the presence of tumor-infiltrating macrophages positively correlates with patient survival in contrast to the negative effect of tumor-associated macrophages in patients with other tumors. Liposome-encapsulated muramyl tripeptide (L-MTP-PE) has been introduced in the treatment of osteosarcoma patients, which may enhance the potential anti-tumor activity of macrophages. Direct anti-tumor activity of human macrophages against human osteosarcoma cells has not been described so far. Hence, we assessed osteosarcoma cell growth after co-culture with human macrophages. METHODS: Monocyte-derived M1-like and M2-like macrophages were polarized with LPS + IFN-γ, L-MTP-PE +/- IFN-γ or IL-10 and incubated with osteosarcoma cells. Two days later, viable tumor cell numbers were analyzed. Antibody-dependent effects were investigated using the therapeutic anti-EGFR antibody cetuximab. RESULTS: M1-like macrophages inhibited osteosarcoma cell growth when activated with LPS + IFN-γ. Likewise, stimulation of M1-like macrophages with liposomal muramyl tripeptide (L-MTP-PE) inhibited tumor growth, but only when combined with IFN-γ. Addition of the tumor-reactive anti-EGFR antibody cetuximab did not further improve the anti-tumor activity of activated M1-like macrophages. The inhibition was mediated by supernatants of activated M1-like macrophages, containing TNF-α and IL-1ß. However, specific blockage of these cytokines, nitric oxide or reactive oxygen species did not inhibit the anti-tumor effect, suggesting the involvement of other soluble factors released upon macrophage activation. While LPS + IFN-γ-activated M2-like macrophages had low anti-tumor activity, IL-10-polarized M2-like macrophages were able to reduce osteosarcoma cell growth in the presence of the anti-EGFR cetuximab involving antibody-dependent tumor cell phagocytosis. CONCLUSION: This study demonstrates that human macrophages can be induced to exert direct anti-tumor activity against osteosarcoma cells. Our observation that the induction of macrophage anti-tumor activity by L-MTP-PE required IFN-γ may be of relevance for the optimization of L-MTP-PE therapy in osteosarcoma patients.


Assuntos
Acetilmuramil-Alanil-Isoglutamina/análogos & derivados , Antineoplásicos/farmacologia , Neoplasias Ósseas/imunologia , Interferon gama/farmacologia , Macrófagos/imunologia , Osteossarcoma/imunologia , Fosfatidiletanolaminas/farmacologia , Acetilmuramil-Alanil-Isoglutamina/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Técnicas de Cocultura , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Interleucina-10/farmacologia , Lipopolissacarídeos/farmacologia , Lipossomos , Osteossarcoma/tratamento farmacológico , Osteossarcoma/patologia
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