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1.
Gut ; 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33414168

RESUMO

OBJECTIVE: Germline pathogenic variants (PVs) in the DNA mismatch repair (MMR) genes and in the base excision repair gene MUTYH underlie hereditary colorectal cancer (CRC) and polyposis syndromes. We evaluated the robustness and discriminatory potential of tumour mutational signatures in CRCs for identifying germline PV carriers. DESIGN: Whole-exome sequencing of formalin-fixed paraffin-embedded (FFPE) CRC tissue was performed on 33 MMR germline PV carriers, 12 biallelic MUTYH germline PV carriers, 25 sporadic MLH1 methylated MMR-deficient CRCs (MMRd controls) and 160 sporadic MMR-proficient CRCs (MMRp controls) and included 498 TCGA CRC tumours. COSMIC V3 single base substitution (SBS) and indel (ID) mutational signatures were assessed for their ability to differentiate CRCs that developed in carriers from non-carriers. RESULTS: The combination of mutational signatures SBS18 and SBS36 contributing >30% of a CRC's signature profile was able to discriminate biallelic MUTYH carriers from all other non-carrier control CRCs with 100% accuracy (area under the curve (AUC) 1.0). SBS18 and SBS36 were associated with specific MUTYH variants p.Gly396Asp (p=0.025) and p.Tyr179Cys (p=5×10-5), respectively. The combination of ID2 and ID7 could discriminate the 33 MMR PV carrier CRCs from the MMRp control CRCs (AUC 0.99); however, SBS and ID signatures, alone or in combination, could not provide complete discrimination (AUC 0.79) between CRCs from MMR PV carriers and sporadic MMRd controls. CONCLUSION: Assessment of SBS and ID signatures can discriminate CRCs from biallelic MUTYH carriers and MMR PV carriers from non-carriers with high accuracy, demonstrating utility as a potential diagnostic and variant classification tool.

2.
J Mol Diagn ; 23(3): 358-371, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33383211

RESUMO

Patients in whom mismatch repair (MMR)-deficient cancer develops in the absence of pathogenic variants of germline MMR genes or somatic hypermethylation of the MLH1 gene promoter are classified as having suspected Lynch syndrome (SLS). Germline whole-genome sequencing (WGS) and targeted and genome-wide tumor sequencing were applied to identify the underlying cause of tumor MMR deficiency in SLS. Germline WGS was performed on samples from 14 cancer-affected patients with SLS, including two sets of first-degree relatives. MMR genes were assessed for germline pathogenic variants, including complex structural rearrangements and noncoding variants. Tumor tissue was assessed for somatic MMR gene mutations using targeted, whole-exome sequencing or WGS. Germline WGS identified pathogenic MMR variants in 3 of the 14 cases (21.4%), including a 9.5-megabase inversion disrupting MSH2 in a mother and daughter. Excluding these 3 MMR carriers, tumor sequencing identified at least two somatic MMR gene mutations in 8 of 11 tumors tested (72.7%). In a second mother-daughter pair, a somatic cause of tumor MMR deficiency was supported by the presence of double somatic MSH2 mutations in their respective tumors. More than 70% of SLS cases had double somatic MMR mutations in the absence of germline pathogenic variants in the MMR or other DNA repair-related genes on WGS, and, therefore, were confidently assigned a noninherited cause of tumor MMR deficiency.

3.
Public Health Genomics ; 23(3-4): 110-121, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32688362

RESUMO

INTRODUCTION: Genomic tests can predict risk and tailor screening recommendations for colorectal cancer (CRC). Primary care could be suitable for their widespread implementation. OBJECTIVE: We aimed to assess the feasibility and acceptability of administering a CRC genomic test in primary care. METHODS: Participants aged 45-74 years recruited from 4 Australian general practices were offered a genomic CRC risk test. Participants received brief verbal information about the test comprising 45 CRC-associated single-nucleotide polymorphisms, before choosing whether to undertake the test. Personalized risks were given to testers. Uptake and knowledge of the genomic test, cancer-specific anxiety (Cancer Worry Scale), psychosocial impact (Multidimensional Impact of Cancer Risk Assessment [MICRA] score), and impact on CRC screening behaviour within 6 months were measured. RESULTS: In 150 participants, test uptake was high (126, 84%), with 125 (83%) having good knowledge of the genomic test. Moderate risk participants were impacted more by the test (MICRA mean: 15.9) than average risk participants (mean: 9.5, difference in means: 6.4, 95% confidence interval (CI): 1.5, 11.2, p = 0.01), but all scores were low. Average risk participants' cancer-specific anxiety decreased (mean differences from baseline: 1 month -0.5, 95% CI: -1.0, -0.1, p = 0.03; 6 months -0.6, 95% CI: -1.0, -0.2, p = 0.01). We found limited evidence for genomic testers being more likely to complete the risk-appropriate CRC screening than non-testers (41 vs. 17%, odds ratio = 3.4, 95% CI: 0.6, 34.8, p = 0.19), but some mediators of screening behaviour were altered in genomic testers. CONCLUSIONS: Genomic testing for CRC risk in primary care is acceptable and likely feasible. Further development of the risk assessment intervention could strengthen the impact on screening behaviour.

4.
Fam Cancer ; 19(3): 197-202, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32060697

RESUMO

The advent of gene panel testing is challenging the previous practice of using clinically defined cancer family syndromes to inform single-gene genetic screening. Individual and family cancer histories that would have previously indicated testing of a single gene or a small number of related genes are now, increasingly, leading to screening across gene panels that contain larger numbers of genes. We have applied a gene panel test that included four DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6 and PMS2) to an Australian population-based case-control-family study of breast cancer. Altogether, eight pathogenic variants in MMR genes were identified: six in 1421 case-families (0.4%, 4 MSH6 and 2 PMS2) and two in 833 control-families (0.2%, one each of MLH1 and MSH2). This testing highlights the current and future challenges for clinical genetics in the context of anticipated gene panel-based population-based screening that includes the MMR genes. This testing is likely to provide additional opportunities for cancer prevention via cascade testing for Lynch syndrome and precision medicine for breast cancer treatment.

5.
Br J Cancer ; 121(10): 869-876, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31551580

RESUMO

BACKGROUND: Type 2 diabetes mellitus and high total cholesterol and triglycerides are known to be associated with increased colorectal cancer risk for the general population. These associations are unknown for people with a germline DNA mismatch repair gene mutation (Lynch syndrome), who are at high risk of colorectal cancer. METHODS: This study included 2023 (56.4% female) carriers with a mismatch repair gene mutation (737 in MLH1, 928 in MSH2, 230 in MSH6, 106 in PMS2, 22 in EPCAM) recruited by the Colon Cancer Family Registry between 1998 and 2012. Weighted Cox regression was used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for the associations between self-reported type 2 diabetes, high cholesterol, triglyceride and colorectal cancer risk. RESULTS: Overall, 802 carriers were diagnosed with colorectal cancer at a median age of 42 years. A higher risk of colorectal cancer was observed in those with self-reported type-2 diabetes (HR 1.92; 95% CI, 1.03-3.58) and high cholesterol (HR 1.76; CI 1.23-2.52) compared with those without these conditions. There was no evidence of high triglyceride being associated with colorectal cancer risk. CONCLUSION: For people with Lynch syndrome, self-reported type-2 diabetes mellitus and high cholesterol were associated with increased colorectal cancer risk.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Neoplasias Colorretais/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Predisposição Genética para Doença , Adulto , Idoso , Idoso de 80 Anos ou mais , Colesterol/sangue , Neoplasias Colorretais/sangue , Neoplasias Colorretais/etiologia , Neoplasias Colorretais/genética , Neoplasias Colorretais Hereditárias sem Polipose/sangue , Neoplasias Colorretais Hereditárias sem Polipose/complicações , Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA/genética , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Molécula de Adesão da Célula Epitelial/genética , Feminino , Mutação em Linhagem Germinativa/genética , Humanos , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Modelos de Riscos Proporcionais , Fatores de Risco , Triglicerídeos/sangue
6.
Fam Cancer ; 18(4): 389-397, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31209717

RESUMO

Before SNP-based risk can be incorporated in colorectal cancer (CRC) screening, the ability of these SNPs to estimate CRC risk for persons with and without a family history of CRC, and the screening implications need to be determined. We estimated the association with CRC of a 45 SNP-based risk using 1181 cases and 999 controls, and its correlation with CRC risk predicted from detailed family history. We estimated the predicted change in the distribution across predefined risk categories, and implications for recommended screening commencement age, from adding SNP-based risk to family history. The inter-quintile risk ratio for colorectal cancer risk of the SNP-based risk was 3.28 (95% CI 2.54-4.22). SNP-based and family history-based risks were not correlated (r = 0.02). For persons with no first-degree relatives with CRC, screening could commence 4 years earlier for women (5 years for men) in the highest quintile of SNP-based risk. For persons with two first-degree relatives with CRC, screening could commence 16 years earlier for men and women in the highest quintile, and 7 years earlier for the lowest quintile. This 45 SNP panel in conjunction with family history, can identify people who could benefit from earlier screening. Risk reclassification by 45 SNPs could inform targeted screening for CRC prevention, particularly in clinical genetics settings when mutations in high-risk genes cannot be identified. Yet to be determined is cost-effectiveness, resources requirements, community, patient and clinician acceptance, and feasibility with potentially ethical, legal and insurance implications.


Assuntos
Neoplasias Colorretais/genética , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Estudos de Casos e Controles , Neoplasias Colorretais/prevenção & controle , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Programas de Rastreamento , Anamnese , Pessoa de Meia-Idade , Razão de Chances
7.
Mol Genet Genomic Med ; 7(7): e00781, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31162827

RESUMO

BACKGROUND: Muir-Torre syndrome is defined by the development of sebaceous skin lesions in individuals who carry a germline mismatch repair (MMR) gene mutation. Loss of expression of MMR proteins is frequently observed in sebaceous skin lesions, but MMR-deficiency alone is not diagnostic for carrying a germline MMR gene mutation. METHODS: Whole exome sequencing was performed on three MMR-deficient sebaceous lesions from individuals with MSH2 gene mutations (Lynch syndrome) and three MMR-proficient sebaceous lesions from individuals without Lynch syndrome with the aim of characterizing the tumor mutational signatures, somatic mutation burden, and microsatellite instability status. Thirty predefined somatic mutational signatures were calculated for each lesion. RESULTS: Signature 1 was ubiquitous across the six lesions tested. Signatures 6 and 15, associated with defective DNA MMR, were significantly more prevalent in the MMR-deficient lesions from the MSH2 carriers compared with the MMR-proficient non-Lynch sebaceous lesions (mean ± SD=41.0 ± 8.2% vs. 2.3 ± 4.0%, p = 0.0018). Tumor mutation burden was, on average, significantly higher in the MMR-deficient lesions compared with the MMR-proficient lesions (23.3 ± 11.4 vs. 1.8 ± 0.8 mutations/Mb, p = 0.03). All four sebaceous lesions observed in sun exposed areas of the body demonstrated signature 7 related to ultraviolet light exposure. CONCLUSION: Tumor mutational signatures 6 and 15 and somatic mutation burden were effective in differentiating Lynch-related from non-Lynch sebaceous lesions.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Síndrome de Muir-Torre/genética , Proteína 2 Homóloga a MutS/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Idoso , Biomarcadores Tumorais , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Reparo de Erro de Pareamento de DNA/genética , Proteínas de Ligação a DNA/genética , Feminino , Mutação em Linhagem Germinativa/genética , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 2 Homóloga a MutS/metabolismo , Mutação , Proteínas Nucleares/genética , Transcriptoma/genética , Sequenciamento Completo do Exoma/métodos
8.
Cancer Cell ; 35(2): 256-266.e5, 2019 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-30753826

RESUMO

Biallelic germline mutations affecting NTHL1 predispose carriers to adenomatous polyposis and colorectal cancer, but the complete phenotype is unknown. We describe 29 individuals carrying biallelic germline NTHL1 mutations from 17 families, of which 26 developed one (n = 10) or multiple (n = 16) malignancies in 14 different tissues. An unexpected high breast cancer incidence was observed in female carriers (60%). Mutational signature analysis of 14 tumors from 7 organs revealed that NTHL1 deficiency underlies the main mutational process in all but one of the tumors (93%). These results reveal NTHL1 as a multi-tumor predisposition gene with a high lifetime risk for extracolonic cancers and a typical mutational signature observed across tumor types, which can assist in the recognition of this syndrome.


Assuntos
Biomarcadores Tumorais/genética , Análise Mutacional de DNA , Desoxirribonuclease (Dímero de Pirimidina)/genética , Perfilação da Expressão Gênica , Mutação em Linhagem Germinativa , Síndromes Neoplásicas Hereditárias/genética , Transcriptoma , Adulto , Idoso , Biomarcadores Tumorais/deficiência , Reparo do DNA/genética , Desoxirribonuclease (Dímero de Pirimidina)/deficiência , Europa (Continente) , Feminino , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Hereditariedade , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Neoplásicas Hereditárias/enzimologia , Síndromes Neoplásicas Hereditárias/patologia , Linhagem , Fenótipo , Medição de Risco , Fatores de Risco , Adulto Jovem
10.
Nat Commun ; 9(1): 3166, 2018 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-30093612

RESUMO

Endometrial cancer is the most commonly diagnosed cancer of the female reproductive tract in developed countries. Through genome-wide association studies (GWAS), we have previously identified eight risk loci for endometrial cancer. Here, we present an expanded meta-analysis of 12,906 endometrial cancer cases and 108,979 controls (including new genotype data for 5624 cases) and identify nine novel genome-wide significant loci, including a locus on 12q24.12 previously identified by meta-GWAS of endometrial and colorectal cancer. At five loci, expression quantitative trait locus (eQTL) analyses identify candidate causal genes; risk alleles at two of these loci associate with decreased expression of genes, which encode negative regulators of oncogenic signal transduction proteins (SH2B3 (12q24.12) and NF1 (17q11.2)). In summary, this study has doubled the number of known endometrial cancer risk loci and revealed candidate causal genes for future study.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias do Endométrio/genética , Predisposição Genética para Doença , Alelos , Cromatina/química , Feminino , Frequência do Gene , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Fatores de Risco , Transdução de Sinais
11.
J Clin Oncol ; 36(29): 2961-2968, 2018 10 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.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Neoplasias/epidemiologia , Neoplasias/genética , Penetrância , Adulto , Idoso , Feminino , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Mutação
12.
Genet Med ; 20(10): 1299, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29388942

RESUMO

The abstract to this article contained errors in the Results and Conclusions section. The corrected sections are shown below.

13.
JCO Precis Oncol ; 20182018.
Artigo em Inglês | MEDLINE | ID: mdl-30854504

RESUMO

Purpose: Patients with Lynch syndrome (LS) have a significantly increased risk of developing upper-tract urothelial carcinoma (UTUC). Here, we sought to identify differences in the patterns of mutational changes in LS-associated versus sporadic UTUCs. Patients and Methods: We performed targeted sequencing of 17 UTUCs from patients with documented LS-associated germline mutations (LS-UTUCs) using the Memorial Sloan Kettering Integrated Molecular Profiling of Actionable Cancer Targets targeted exon capture assay and compared the results with those from a recently characterized cohort of 82 patients with sporadic UTUC. Results: Patients with LS-UTUC were significantly younger, had had less exposure to tobacco, and more often presented with a ureteral primary site compared with patients with sporadic UTUC. The median number of mutations per tumor was significantly greater in LS-UTUC tumors than in tumors from the sporadic cohort (58; interquartile range [IQR], 47-101 v 6; IQR, 4-10; P < .001), as was the MSIsensor score (median, 25.1; IQR, 17.9-31.2 v 0.03; IQR, 0-0.44; P < .001). Differences in the genetic landscape were observed between sporadic and LS-associated tumors. Alterations in KMT2D, CREBBP, or ARID1A or in DNA damage response and repair genes were present at a significantly higher frequency in LS-UTUC. CIC, NOTCH1, NOTCH3, RB1, and CDKN1B alterations were almost exclusive to LS-UTUC. Although FGFR3 mutations were identified in both cohorts, the R248C hotspot mutation was highly enriched in LS-UTUC. Conclusion: LSand sporadic UTUCs have overlapping but distinct genetic signatures. LS-UTUC is associated with hypermutation and a significantly higher prevalence of FGFR3 R248C mutation. Prospective molecular characterization of patients to identify those with LS-UTUC may help guide treatment.

14.
Int J Cancer ; 142(2): 238-250, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-28921583

RESUMO

The influence of lifestyle factors on survival following a diagnosis of colorectal cancer (CRC) is not well established. We examined associations between lifestyle factors measured before diagnosis and CRC survival. The Melbourne Collaborative Cohort Study collected data on alcohol intake, cigarette smoking and physical activity, and body measurements at baseline (1990-1994) and wave 2 (2003-2007). We included participants diagnosed to 31 August 2015 with incident stages I-III CRC within 10-years post exposure assessment. Information on tumor characteristics and vital status was obtained. Tumor DNA was tested for microsatellite instability (MSI) and somatic mutations in oncogenes BRAF (V600E) and KRAS. We estimated hazard ratios (HRs) for associations between lifestyle factors and overall and CRC-specific mortality using Cox regression. Of 724 eligible CRC cases, 339 died (170 from CRC) during follow-up (average 9.0 years). Exercise (non-occupational/leisure-time) was associated with higher CRC-specific survival for stage II (HR = 0.25, 95% CI: 0.10-0.60) but not stages I/III disease (p for interaction = 0.01), and possibly for colon and KRAS wild-type tumors. Waist circumference was inversely associated with CRC-specific survival (HR = 1.25 per 10 cm increment, 95% CI: 1.08-1.44), independent of stage, anatomic site and tumor molecular status. Cigarette smoking was associated with lower overall survival, with suggestive evidence of worse survival for BRAF mutated CRC, but not with CRC-specific survival. Alcohol intake was not associated with survival. Survival did not differ by MSI status. We have identified pre-diagnostic predictors of survival following CRC that may have clinical and public health relevance.


Assuntos
Adenocarcinoma/mortalidade , Consumo de Bebidas Alcoólicas/efeitos adversos , Neoplasias Colorretais/mortalidade , Exercício Físico , Obesidade/complicações , Fumar/efeitos adversos , Adenocarcinoma/classificação , Adenocarcinoma/diagnóstico , Adenocarcinoma/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/classificação , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/etiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , Taxa de Sobrevida
15.
Fam Cancer ; 17(1): 63-69, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28573495

RESUMO

The WNT signaling pathway is commonly altered during colorectal cancer development. The E3 ubiquitin ligase, RNF43, negatively regulates the WNT signal through increased ubiquitination and subsequent degradation of the Frizzled receptor. RNF43 has recently been reported to harbor frequent truncating frameshift mutations in sporadic microsatellite unstable (MSI) colorectal cancers. This study assesses the relative frequency of RNF43 mutations in hereditary colorectal cancers arising in the setting of Lynch syndrome. The entire coding region of RNF43 was Sanger sequenced in 24 colorectal cancers from 23 patients who either (i) carried a germline mutation in one of the DNA mismatch repair genes (MLH1, MSH6, MSH2, PMS2), or (ii) showed immunohistochemical loss of expression of one or more of the DNA mismatch repair proteins, was BRAF wild type at V600E, were under 60 years of age at diagnosis, and demonstrated no promoter region methylation for MLH1 in tumor DNA. A validation cohort of 44 colorectal cancers from mismatch repair germline mutation carriers from the Australasian Colorectal Cancer Family Registry (ACCFR) were sequenced for the most common truncating mutation hotspots (X117 and X659). RNF43 mutations were found in 9 of 24 (37.5%) Lynch syndrome colorectal cancers. The majority of mutations were frameshift deletions in the G659 G7 repeat tract (29%); 2 cancers (2/24, 8%) from the one patient harbored frameshift mutations at codon R117 (C6 repeat tract) within exon 3. In the ACCFR validation cohort, RNF43 hotspot mutations were identified in 19/44 (43.2%) of samples, which was not significantly different to the initial series. The proportion of mutant RNF43 in Lynch syndrome related colorectal cancers is significantly lower than the previously reported mutation rate found in sporadic MSI colorectal cancers. These findings identify further genetic differences between sporadic and hereditary colorectal cancers. This may be because Lynch Syndrome cancers commonly arise in colorectal adenomas already bearing the APC mutation, whereas sporadic microsatellite unstable colorectal cancers arise from serrated polyps typically lacking APC mutation, decreasing the selection pressure on other WNT signaling related loci in Lynch syndrome.


Assuntos
Adenoma/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais/genética , Proteínas de Ligação a DNA/genética , Instabilidade de Microssatélites , Proteínas Oncogênicas/genética , Proteína da Polipose Adenomatosa do Colo/genética , Adulto , Idoso , Estudos de Coortes , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Seleção Genética , Ubiquitina-Proteína Ligases , Via de Sinalização Wnt/genética
16.
Fam Cancer ; 17(1): 91-100, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28616688

RESUMO

In colorectal cancers (CRCs) with tumour mismatch repair (MMR) deficiency, genes involved in the host immune response that contain microsatellites in their coding regions, including beta-2-microglobulin (B2M), can acquire mutations that may alter the immune response, tumour progression and prognosis. We screened the coding microsatellites within B2M for somatic mutations in MMR-deficient CRCs and adenomas to determine associations with tumour subtypes, clinicopathological features and survival. Incident MMR-deficient CRCs from Australasian Colorectal Cancer Family Registry (ACCFR) and the Melbourne Collaborative Cohort Study participants (n = 144) and 63 adenomas from 41 MMR gene mutation carriers from the ACCFR were screened for somatic mutations within five coding microsatellites of B2M. Hazard ratios (HR) and 95% confidence intervals (CI) for overall survival by B2M mutation status were estimated using Cox regression, adjusting for age at CRC diagnosis, sex, AJCC stage and grade. B2M mutations occurred in 30 (20.8%) of the 144 MMR-deficient CRCs (29% of the MLH1-methylated, 17% of the Lynch syndrome and 9% of the suspected Lynch CRCs). No B2M mutations were identified in the 63 adenomas tested. B2M mutations differed by site, stage, grade and lymphocytic infiltration although none reached statistical significance (p > 0.05). The HR for overall survival for B2M mutated CRC was 0.65 (95% CI 0.29-1.48) compared with B2M wild-type. We observed differences in B2M mutation status in MMR-deficient CRC by tumour subtypes, site, stage, grade, immune infiltrate and for overall survival that warrant further investigation in larger studies before B2M mutation status can be considered to have clinical utility.


Assuntos
Adenoma/genética , Neoplasias Encefálicas/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais/genética , Repetições de Microssatélites/genética , Síndromes Neoplásicas Hereditárias/genética , Microglobulina beta-2/genética , Adenoma/mortalidade , Adulto , Idoso , Neoplasias Encefálicas/mortalidade , Estudos de Coortes , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais Hereditárias sem Polipose/mortalidade , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Síndromes Neoplásicas Hereditárias/mortalidade , Adulto Jovem
17.
Genet Med ; 20(8): 890-895, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29120461

RESUMO

BACKGROUND: Germ-line mutations in the exonuclease domains of the POLE and POLD1 genes are associated with an increased, but yet unquantified, risk of colorectal cancer (CRC). METHODS: We identified families with POLE or POLD1 variants by searching PubMed for relevant studies prior to October 2016 and by genotyping 669 population-based CRC cases diagnosed in patients under 60 years of age, from the Australasian Colorectal Cancer Family Registry. We estimated the age-specific cumulative risks (penetrance) using a modified segregation analysis. RESULTS: We observed 67 CRCs (mean age at diagnosis = 50.2 (SD = 13.8) years) among 364 first- and second-degree relatives from 41 POLE families, and 6 CRCs (mean age at diagnosis = 39.7 (SD = 6.83) years) among 69 relatives from 9 POLD1 families. We estimated risks of CRC up to the age of 70 years (95% confidence interval) for males and females, respectively, to be 28% (95% CI, 10­42%) and 21% (95% CI, 7­33%) for POLE mutation carriers and 90% (95% CI, 33­99%) and 82% (95% CI, 26­99%) for POLD1 mutation carriers. CONCLUSION: CRC risks for POLE mutation carriers are sufficiently high to warrant consideration of colonoscopy screening and implementation of management guidelines recommended for MSH6 mutation carriers in cases of Lynch syndrome. Refinement of estimates of CRC risk for POLD1 carriers is needed; however, clinical management recommendations could follow those made for POLE carriers.


Assuntos
Neoplasias Colorretais/genética , DNA Polimerase III/genética , DNA Polimerase II/genética , Proteínas de Ligação a Poli-ADP-Ribose/genética , Adulto , Idoso , DNA Polimerase II/fisiologia , DNA Polimerase III/fisiologia , Bases de Dados Genéticas , Feminino , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa/genética , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Penetrância , Proteínas de Ligação a Poli-ADP-Ribose/fisiologia , Risco , Fatores de Risco
18.
Oncotarget ; 8(55): 93450-93463, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-29212164

RESUMO

The underlying genetic cause of colorectal cancer (CRC) can be identified for 5-10% of all cases, while at least 20% of CRC cases are thought to be due to inherited genetic factors. Screening for highly penetrant mutations in genes associated with Mendelian cancer syndromes using next-generation sequencing (NGS) can be prohibitively expensive for studies requiring large samples sizes. The aim of the study was to identify rare single nucleotide variants and small indels in 40 established or candidate CRC susceptibility genes in 1,046 familial CRC cases (including both MSS and MSI-H tumor subtypes) and 1,006 unrelated controls from the Colon Cancer Family Registry Cohort using a robust and cost-effective DNA pooling NGS strategy. We identified 264 variants in 38 genes that were observed only in cases, comprising either very rare (minor allele frequency <0.001) or not previously reported (n=90, 34%) in reference databases, including six stop-gain, three frameshift, and 255 non-synonymous variants predicted to be damaging. We found novel germline mutations in established CRC genes MLH1, APC, and POLE, and likely pathogenic variants in cancer susceptibility genes BAP1, CDH1, CHEK2, ENG, and MSH3. For the candidate CRC genes, we identified likely pathogenic variants in the helicase domain of POLQ and in the LRIG1, SH2B3, and NOS1 genes and present their clinicopathological characteristics. Using a DNA pooling NGS strategy, we identified novel germline mutations in established CRC susceptibility genes in familial CRC cases. Further studies are required to support the role of POLQ, LRIG1, SH2B3 and NOS1 as CRC susceptibility genes.

19.
Mol Genet Genomic Med ; 5(5): 553-569, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28944238

RESUMO

BACKGROUND: Mutations in several genes predispose to colorectal cancer. Genetic testing for hereditary colorectal cancer syndromes was previously limited to single gene tests; thus, only a very limited number of genes were tested, and rarely those infrequently mutated in colorectal cancer. Next-generation sequencing technologies have made it possible to sequencing panels of genes known and suspected to influence colorectal cancer susceptibility. METHODS: Targeted sequencing of 36 known or putative CRC susceptibility genes was conducted for 1231 CRC cases from five subsets: (1) Familial Colorectal Cancer Type X (n = 153); (2) CRC unselected by tumor immunohistochemical or microsatellite stability testing (n = 548); (3) young onset (age <50 years) (n = 333); (4) proficient mismatch repair (MMR) in cases diagnosed at ≥50 years (n = 68); and (5) deficient MMR CRCs with no germline mutations in MLH1, MSH2, MSH6, or PMS2 (n = 129). Ninety-three unaffected controls were also sequenced. RESULTS: Overall, 29 nonsense, 43 frame-shift, 13 splice site, six initiator codon variants, one stop codon, 12 exonic deletions, 658 missense, and 17 indels were identified. Missense variants were reviewed by genetic counselors to determine pathogenicity; 13 were pathogenic, 61 were not pathogenic, and 584 were variants of uncertain significance. Overall, we identified 92 cases with pathogenic mutations in APC,MLH1,MSH2,MSH6, or multiple pathogenic MUTYH mutations (7.5%). Four cases with intact MMR protein expression by immunohistochemistry carried pathogenic MMR mutations. CONCLUSIONS: Results across case subsets may help prioritize genes for inclusion in clinical gene panel tests and underscore the issue of variants of uncertain significance both in well-characterized genes and those for which limited experience has accumulated.

20.
N Z Med J ; 130(1451): 57-67, 2017 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-28253245

RESUMO

BACKGROUND: Serrated polyposis syndrome (SPS) is associated with an increased risk of colorectal cancer (CRC) and an evolving management approach. The aims of this study were to assess the polyp burden reduction over time, and the incidence of CRC in serrated polyposis patients undergoing community surveillance. METHODS: This is an observational study based on prospectively collected data. A total of 96 SPS patients with no personal history of CRC were prospectively enrolled in a surveillance program under the guidance of a tertiary center. Patients underwent surveillance colonoscopy in multiple centres across New Zealand. RESULTS: Patients underwent a median of four colonoscopies with a median interval of 15 months over a median follow-up period of 4.8 years. Five of 96 patients (5%) were referred for surgery, and the remaining 91 were managed by colonoscopy alone. In patients referred for surgery, 92% of the surveillance intervals to the fourth colonoscopy had been ≤12 months compared to 33% (P<0.001) in the colonoscopy only group, and all five (100%) had ≥20 pancolonic polyps after four procedures compared with only 5/91 (5%) in those managed by colonoscopy alone. In patients successfully managed by colonoscopy, 86% had <10 pancolonic polyps, >75% no longer had polyps ≥10mm and >90% no longer had proximal serrated polyps ≥10mm after the fourth colonoscopy. No patients were found to develop CRC during the study time period. CONCLUSIONS: Patients with SPS were managed by proactive surveillance colonoscopy in wider hospital settings under tertiary centre guidance, with only 5% requiring surgical management. No CRC was diagnosed in any patient during surveillance.


Assuntos
Pólipos do Colo/diagnóstico , Pólipos do Colo/terapia , Colonoscopia/métodos , Neoplasias Colorretais/epidemiologia , Programas de Rastreamento/métodos , Adulto , Pólipos do Colo/patologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Nova Zelândia/epidemiologia , Fatores de Risco , Fatores de Tempo
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