Increased cancer predisposition in family members of colorectal cancer patients harboring the p.V600E BRAF mutation: a population-based study

BRAF p.V600E associated poly-neoplastic syndrome

We report a male patient who developed eight different cancers between ages 57 and 64. BRAF p.V600E mutation was detected in Langerhans cell histiocytosis, chronic lymphocytic leukemia, histiocytic sarcoma, melanoma, and adenocarcinoma of the lung. It was not detected in multiple myeloma, basal cell carcinoma, and papillary thyroid cancer. BRAF p.V600E was not detected in normal skin tissue biopsy indicating that BRAF V600E was a somatic mutation affecting cancer cells. The presence of eight different cancers with five of them positive for BRAF p.V600E in a single patient is unprecedented. This type of BRAF p.V600E-associated poly-neoplastic syndrome has never been reported in the medical literature.

BRAF V600E Expression by Immunohistochemistry in Colon Cancer and Clinico-pathologic Features Associated with BRAF-Mutated Colonic Cancers in Mexican Patients

BACKGROUND

BRAF evaluation is currently limited to molecular techniques, which are expensive and not widely available to practicing pathologists. Our objective was to determine the diagnostic performance of immunohistochemistry (IHC) against BRAF V600E for BRAF mutation and the secondary objective was determining histopathological characteristics of colon carcinomas with BRAF mutated.

METHODS

Cases of adenocarcinoma of the colon with a known BRAF mutation status were identified from the pathological files of our institution.

RESULTS

We analyzed 135 cases, 13 cases had the BRAF mutation (9.6%) and 122 were non-mutated. The mutated cases expressed intense and diffusely the anti-antibody against BRAF V600E, and 119 (97.5%) of the 122 cases without mutation were negative and the remaining 3 were focal and weakly positive. The IHC demonstrated a sensitivity of 100%, specificity of 97.5%, positive predictive value of 81.3% (95% CI = 56.9 to 93.4%), negative predictive value of 100% (95% CI = 89 to 100%), and an overall accuracy of 97.8%. The only significant clinicopathological differences between cancers with BRAF mutated compared with BRAF non-mutated were that mutated had less lymph node metastases (23% vs. 68.1%) and the tumor size was greater (median 90 mm vs. 60 mm). The survival between groups was not statistically significant.

CONCLUSION

IHC against BRAF V600E showed an excellent performance, making it feasible as an alternative for molecular examination. Tumors with BRAF mutated did not show distinctive clinico-pathological characteristics, except for a larger tumor size.

A genome-wide association study identifies single nucleotide polymorphisms associated with time-to-metastasis in colorectal cancer

Background

Differentiating between cancer patients who will experience metastasis within a short time and who will be long-term survivors without metastasis is a critical aim in healthcare. The microsatellite instability (MSI)-high tumor phenotype is such a differentiator in colorectal cancer, as patients with these tumors are unlikely to experience metastasis. Our aim in this study was to determine if germline genetic variations could further differentiate colorectal cancer patients based on the long-term risk and timing of metastasis.

Methods

The patient cohort consisted of 379 stage I-III Caucasian colorectal cancer patients with microsatellite stable or MSI-low tumors. We performed univariable analysis on 810,622 common single nucleotide polymorphisms (SNPs) under different genetic models. Depending on the long-term metastasis-free survival probability estimates, we applied a mixture cure model, Cox proportional hazards regression model, or log-rank test. For SNPs reaching Bonferroni-corrected significance (p < 6.2 × 10^− 8) having valid genetic models, multivariable analysis adjusting for significant baseline characteristics was conducted.

Results

After adjusting for significant baseline characteristics, specific genotypes of ten polymorphisms were significantly associated with time-to-metastasis. These polymorphisms are three intergenic SNPs, rs5749032 (p = 1.28 × 10^− 10), rs2327990 (p = 9.59 × 10^− 10), rs1145724 (p = 3 × 10^− 8), and seven SNPs within the non-coding sequences of three genes: FHIT (p = 2.59 × 10^− 9), EPHB1 (p = 8.23 × 10^− 9), and MIR7515 (p = 4.87 × 10^− 8).

Conclusions

Our results suggest novel associations of specific genotypes of SNPs with early metastasis in Caucasian colorectal cancer patients. These associations, once replicated in other patient cohorts, could assist in the development of personalized treatment strategies for colorectal cancer patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5346-5) contains supplementary material, which is available to authorized users.

Helicobacter pylori is associated with increased risk of serrated colonic polyps: Analysis of serrated polyp risk factors

BACKGROUND

Sessile serrated adenomas (SSA) and traditional serrated adenomas (TSA) are recognized precursors of colorectal cancer, but their risk factors are not well established. We investigated the association between Helicobacter pylori infection (HPI) and the development of SSA and TSA.

METHODS

Retrospective data were collected on patients aged ≥ 18 years that underwent colonoscopy with biopsy between 2006 and 2016. Based on histology, patients were classified into three groups: those with SSA and/or TSA, (serrated neoplasia group, SN); conventional adenomas only (CA); and with no polyps (NP). Gastric HPI status, demographic, and clinical risk factors were compared between groups using bivariate and multivariable analysis.

RESULTS

HPI was significantly associated with increased risk of SN (SN vs. NP: OR 1.71 [95% CI 1.29-2.27]; SN vs. CA: 1.49 [1.14-1.96]). Additional factors associated with increased risk of SN included the following: age 50-75 years, compared to younger age (SN vs. NP: 2.83 [1.69-4.74]), female gender (SN vs. CA: 1.28 [0.99-1.64]), White race, compared to Blacks (SN vs. CA: 1.52 [1.07-2.15)], overweight and obese body mass index [SN vs. NP: p < 0.001) and current smoking status (SN vs. CA: 2.09 [1.55-2.82)]. Among SN, higher HPI prevalence was associated with dysplasia (p = 0.05) and proximal location (p = 0.01).

CONCLUSIONS

Our data suggest that gastric HPI is associated with increased risk of SN and CA, with a stronger association with SN as compared to CA. Age 50-75 years, female gender, White race, obesity, and smoking were also predictors of SN. A positive correlation of HPI with proximal and dysplastic SN suggests a possible role in serrated pathway carcinogenesis. Prospective studies with large patient population are needed to further investigate this association.

XRCC3 Thr241Met and TYMS variable number tandem repeat polymorphisms are associated with time-to-metastasis in colorectal cancer

Background

Metastasis is a major cause of mortality in cancer. Identifying prognostic factors that distinguish patients who will experience metastasis in the short-term and those that will be free of metastasis in the long-term is of particular interest in current medical research. The objective of this study was to examine if select genetic polymorphisms can differentiate colorectal cancer patients based on timing and long-term risk of metastasis.

Methods

The patient cohort consisted of 402 stage I-III colorectal cancer patients with microsatellite instability (MSI)-low (MSI-L) or microsatellite stable (MSS) tumors. We applied multivariable mixture cure model, which is the proper model when there is a substantial group of patients who remain free of metastasis in the long-term, to 26 polymorphisms. Time-dependent receiver operator characteristic (ROC) curve analysis was performed to determine the change in discriminatory accuracy of the models when the significant SNPs were included.

Results

After adjusting for significant baseline characteristics, two polymorphisms were significantly associated with time-to-metastasis: TT and TC genotypes of the XRCC3 Thr241Met (p = 0.042) and the 3R/3R genotype of TYMS 5’-UTR variable number tandem repeat (VNTR) (p = 0.009) were associated with decreased time-to-metastasis. ROC curves showed that the discriminatory accuracy of the model is increased slightly when these polymorphisms were added to the significant baseline characteristics.

Conclusions

Our results indicate XRCC3 Thr241Met and TYMS 5’-UTR VNTR polymorphisms are associated with time-to-metastasis, and may have potential biological roles in expediting the metastatic process. Once replicated, these associations could contribute to the development of precision medicine for colorectal cancer patients.

Role of tumour molecular and pathology features to estimate colorectal cancer risk for first-degree relatives

OBJECTIVE

To estimate risk of colorectal cancer (CRC) for first-degree relatives of CRC cases based on CRC molecular subtypes and tumour pathology features.

DESIGN

We studied a cohort of 33,496 first-degree relatives of 4853 incident invasive CRC cases (probands) who were recruited to the Colon Cancer Family Registry through population cancer registries in the USA, Canada and Australia. We categorised the first-degree relatives into four groups: 28,156 of 4095 mismatch repair (MMR)-proficient probands, 2302 of 301 MMR-deficient non-Lynch syndrome probands, 1799 of 271 suspected Lynch syndrome probands and 1239 of 186 Lynch syndrome probands. We compared CRC risk for first-degree relatives stratified by the absence or presence of specific tumour molecular pathology features in probands across each of these four groups and for all groups combined.

RESULTS

Compared with first-degree relatives of MMR-proficient CRC cases, a higher risk of CRC was estimated for first-degree relatives of CRC cases with suspected Lynch syndrome (HR 2.06, 95% CI 1.59 to 2.67) and with Lynch syndrome (HR 5.37, 95% CI 4.16 to 6.94), but not with MMR-deficient non-Lynch syndrome (HR 1.04, 95% CI 0.82 to 1.31). A greater risk of CRC was estimated for first-degree relatives if CRC cases were diagnosed before age 50 years, had proximal colon cancer or if their tumours had any of the following: expanding tumour margin, peritumoral lymphocytes, tumour-infiltrating lymphocytes or synchronous CRC.

CONCLUSIONS

Molecular pathology features are potentially useful to refine screening recommendations for first-degree relatives of CRC cases and to identify which cases are more likely to be caused by genetic or other familial factors.

Risk factors for serrated polyps of the colorectum

Serrated pathway polyps are a relatively new area of interest in the field of colorectal cancer screening and prevention. Akin to conventional adenomas, some serrated polyps (SPs) have the potential to develop into malignant serrated neoplasms, yet little is known regarding risk factors for these lesions. Early epidemiological studies of hyperplastic polyps were performed without knowledge of the serrated pathway and likely included a mixture of SPs. More recently, studies have specifically evaluated premalignant SPs, such as the sessile serrated adenoma (SSA) or surrogates for these polyps such as large or proximally located SPs. SPs share some risk factors with conventional adenomas and have been associated with tobacco use, obesity, and age. Nonsteroidal anti-inflammatory drug (NSAID) use, fiber, folic acid, and calcium have been associated with reduced risk of SPs. Studies focused on SSAs specifically have reported associations with age, female sex, smoking, obesity, diabetes, and possibly diets high in fat, carbohydrates, and calories. Higher education has also been associated with risk of SSAs, while an inverse association between NSAID use and SSAs has been reported. Risk factors for traditional serrated adenomas are largely unknown. Studies are largely limited by varying inclusion criteria, as well as differences in pathological classification schemes. Further epidemiological studies of SPs are needed to aid in risk stratification and screening, and etiological research.

BRAF-activated long non-coding RNA contributes to colorectal cancer migration by inducing epithelial-mesenchymal transition

Long non-coding RNAs (lncRNAs) are recently identified regulators in tumorigenesis and tumour progression. BRAF-activated lncRNA (BANCR) is overexpressed in melanoma and has a potential functional role in melanoma cell migration. However, little is known concerning the role of BANCR in the development of colorectal cancer (CRC). The current study examined BANCR expression in 60 pairs of CRC and matched adjacent normal tissues. The quantitative polymerase chain reaction results showed that BANCR was frequently overexpressed in cancer tissues and this overexpression was found to significantly correlate with lymph node metastasis and tumour stage. The ectopic expression of BANCR contributed to the migration of human CRC Caco-2 cells, whereas knockdown of BANCR inhibited the migration of the HCT116 cells in vitro. Further investigation into the underlying mechanisms responsible for the migratory effects revealed that BANCR induced the epithelial-mesenchymal transition (EMT) through an MEK/extracellular signal-regulated kinase-dependent mechanism as treatment with the MEK inhibitor, U0126 decreased migration and reversed the EMT in the BANCR-overexpressed HCT116 cells. These results revealed the significance of BANCR in the molecular etiology of CRC and implied the potential application of BANCR in the therapeutic treatment of CRC.

Influence of pre-diagnostic cigarette smoking on colorectal cancer survival: overall and by tumour molecular phenotype

BACKGROUND

Smoking is a risk factor for incident colorectal cancer (CRC); however, it is unclear about its influence on survival after CRC diagnosis.

METHODS

A cohort of 706 CRC patients diagnosed from 1999 to 2003 in Newfoundland and Labrador, Canada, was followed for mortality and recurrence until April 2010. Smoking and other relevant data were collected by questionnaire after cancer diagnosis, using a referent period of '2 years before diagnosis' to capture pre-diagnosis information. Molecular analyses of microsatellite instability (MSI) status and BRAF V600E mutation status were performed in tumour tissue using standard techniques. Multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with Cox proportional hazards regression, controlling for major prognostic factors.

RESULTS

Compared with never smokers, all-cause mortality (overall survival, OS) was higher for current (HR: 1.78; 95% CI: 1.04-3.06), but not for former (HR: 1.06; 95% CI: 0.71-1.59) smokers. The associations of cigarette smoking with the study outcomes were higher among patients with ≥40 pack-years of smoking (OS: HR: 1.72; 95% CI: 1.03-2.85; disease-free survival (DFS: HR: 1.99; 95% CI: 1.25-3.19), those who smoked ≥30 cigarettes per day (DFS: HR: 1.80; 95% CI: 1.22-2.67), and those with microsatellite stable (MSS) or MSI-low tumours (OS: HR: 1.38; 95% CI: 1.04-1.82 and DFS: HR: 1.32; 95% CI: 1.01-1.72). Potential heterogeneity was noted for sex (DFS HR: 1.68 for men and 1.01 for women: P for heterogeneity=0.04), and age at diagnosis (OS: HR: 1.11 for patients aged <60 and 1.69 for patients aged ≥60: P for heterogeneity=0.03).

CONCLUSIONS

Pre-diagnosis cigarette smoking is associated with worsened prognosis among patients with CRC.

Population-based molecular screening for Lynch syndrome: implications for personalized medicine

PURPOSE

Molecular screening techniques are available to identify hereditary Lynch syndrome in people with newly diagnosed colorectal cancer (CRC). We aimed to determine whether decisions of patients or clinicians reduced detection of Lynch syndrome.

PATIENTS AND METHODS

A prospective cohort of 245 consecutive individuals with mismatch repair-deficient CRC recruited from a population-based molecular screening program of all incident patient cases of CRC in a health care region of 1.2 million inhabitants. All incident CRCs were analyzed for mismatch repair protein loss, supported by BRAF mutation and microsatellite instability testing. Advice regarding referral for germline testing was provided to treating surgeons.

RESULTS

The mean age of patients was 72.5 ± standard deviation of 12 years; 64% were women; 65% had BRAF-mutant cancers. Consent for germline testing was received from 194 patients (79%): 120 with low and 74 with high likelihood of Lynch syndrome based on tumor molecular profile. Of patients who consented, 143 provided samples for germline analysis, with 12 of 143 showing a mutation (8.4%; 95% CI, 4.4% to 14.2%). Among the 102 patients who chose not to provide a sample or did not consent, an estimated 5.3 of 102 had germline mutations (5.2%; 95% CI, 2.0% to 17.5%).

CONCLUSION

A universal screening strategy for Lynch syndrome is potentially effective because the overall estimate of germline mutations was 17.3 of 245 patient cases (7.1%; 95% CI, 2.8% to 18.2%). However, the true value of screening is likely to be greatly limited by the decisions and circumstances of patients in taking up germline testing.

BRAF V600E mutation detection by immunohistochemistry in colorectal carcinoma

The serine/threonine-protein kinase B-raf (BRAF) is an oncogene mutated in various neoplasms, including 5-15% of colorectal carcinomas. The T1799A point mutation, responsible for a large majority of these alterations, results in an amino acid substitution (V600E) causing the constitutive activation of a protein kinase cascade. BRAF V600E in MLH1 deficient tumors implicates somatic tumor-only methylation of the MLH1 promoter region instead of a germline MLH1 mutation. BRAF V600E also predicts poor prognosis in microsatellite stable colorectal cancers and may be a marker of resistance to anti-EGFR therapy in metastatic disease. Currently, only molecular methods are available for assessing BRAF mutational status. An immunohistochemical approach is evaluated here. Colon cancers from 2008 to 2012 tested by pyrosequencing for BRAF V600E mutation were selected. A total of 31 tumors with (n = 14) and without (n = 17) the BRAF V600E mutation were analyzed by immunohistochemistry using a commercially available antibody specific to the V600E-mutated protein. All 14 colorectal carcinomas with the BRAF V600E mutation demonstrated cytoplasmic positivity in tumor cells with the anti-BRAF antibody. In a minority of cases, staining intensity for the mutated tumor samples was weak (n = 2) or heterogeneous (n = 4); however, the majority of cases showed diffuse, strong cytoplasmic positivity (8 of 14 cases). None of the 17 BRAF wild-type colorectal cancers showed immunoreactivity to the antibody. The overall sensitivity and specificity of the immunohistochemical BRAF V600E assay was 100%. Detection of the BRAF V600E mutation in colorectal cancer by immunohistochemistry is a viable alternative to molecular methods.

MTHFR Glu429Ala and ERCC5 His46His polymorphisms are associated with prognosis in colorectal cancer patients: analysis of two independent cohorts from Newfoundland

Introduction

In this study, 27 genetic polymorphisms that were previously reported to be associated with clinical outcomes in colorectal cancer patients were investigated in relation to overall survival (OS) and disease free survival (DFS) in colorectal cancer patients from Newfoundland.

Methods

The discovery and validation cohorts comprised of 532 and 252 patients, respectively. Genotypes of 27 polymorphisms were first obtained in the discovery cohort and survival analyses were performed assuming the co-dominant genetic model. Polymorphisms associated with disease outcomes in the discovery cohort were then investigated in the validation cohort.

Results

When adjusted for sex, age, tumor stage and microsatellite instability (MSI) status, four polymorphisms were independent predictors of OS in the discovery cohort MTHFR Glu429Ala (HR: 1.72, 95%CI: 1.04–2.84, p = 0.036), ERCC5 His46His (HR: 1.78, 95%CI: 1.15–2.76, p = 0.01), SERPINE1 −675indelG (HR: 0.52, 95%CI: 0.32–0.84, p = 0.008), and the homozygous deletion of GSTM1 gene (HR: 1.4, 95%CI: 1.03–1.92, p = 0.033). In the validation cohort, the MTHFR Glu429Ala polymorphism was associated with shorter OS (HR: 1.71, 95%CI: 1.18–2.49, p = 0.005), although with a different genotype than the discovery cohort (CC genotype in the discovery cohort and AC genotype in the validation cohort). When stratified based on treatment with 5-Fluorouracil (5-FU)-based regimens, this polymorphism was associated with reduced OS only in patients not treated with 5-FU. In the DFS analysis, when adjusted for other variables, the TT genotype of the ERCC5 His46His polymorphism was associated with shorter DFS in both cohorts (discovery cohort: HR: 1.54, 95%CI: 1.04–2.29, p = 0.032 and replication cohort: HR: 1.81, 95%CI: 1.11–2.94, p = 0.018).

Conclusions

In this study, associations of the MTHFR Glu429Ala polymorphism with OS and the ERCC5 His46His polymorphism with DFS were identified in two colorectal cancer patient cohorts. Our results also suggest that the MTHFR Glu429Ala polymorphism may be an adverse prognostic marker in patients not treated with 5-FU.

Family history of colorectal cancer in BRAF p.V600E-mutated colorectal cancer cases

BACKGROUND

Previous reports suggest that relatives of colorectal cancer (CRC)-affected probands carrying the BRAF p.V600E mutation are at an increased risk of CRC and extracolonic cancers (ECC). In this study, we estimated the association between a family history of either CRC or ECC and risk of CRC with a BRAF p.V600E mutation.

METHODS

Population-based CRC cases (probands, ages 18-59 years at diagnosis), recruited irrespective of family cancer history, were characterized for BRAF p.V600E mutation and mismatch repair (MMR) status. ORs and 95% confidence intervals (CI) were estimated using multivariable logistic regression.

RESULTS

The 690 eligible probands showed a mean age at CRC diagnosis of 46.9 ± 7.8 years, with 313 (47.9%) reporting a family history of CRC and 53 (7.7%) that were BRAF-mutated. Probands with BRAF-mutated, MMR-proficient CRCs were less likely to have a family history of CRC than probands that were BRAF wild-type (OR, 0.46; 95% CI, 0.24-0.91; P = 0.03). For probands with a BRAF-mutated CRC, the mean age at diagnosis was greater for those with a CRC-affected first- or second-degree relative (49.3 ± 6.4 years) compared with those without a family history (43.8 ± 10.2 years; P = 0.04). The older the age at diagnosis of CRC with the BRAF p.V600E mutation, the more likely these probands were to show a family history of CRC (OR, 1.09 per year of age; 95% CI, 1.00-1.18; P = 0.04).

CONCLUSIONS

Probands with early-onset, BRAF-mutated, and MMR-proficient CRC were less likely to have a family history of CRC than probands that were BRAF-wild-type.

IMPACT

These findings provide useful insights for cancer risk assessment in families and suggest that familial or inherited factors are more important in early-onset, BRAF-wild-type CRC.

Serrated polyps of the large intestine: current understanding of diagnosis, pathogenesis, and clinical management

Approximately 30% of colorectal carcinomas develop via the serrated neoplasia pathway characterized by widespread DNA methylation and frequent BRAF mutation. Serrated polyps represent a heterogeneous group of polyps which are the precursor lesions to serrated pathway colorectal carcinomas. The histological classification of serrated polyps has evolved over the last two decades to distinguish three separate entities: hyperplastic polyp, sessile serrated adenoma (SSA), and traditional serrated adenoma (TSA). The malignant potential of SSAs and TSAs has been clearly demonstrated. SSAs are more challenging to detect by colonoscopy and are likely to account for some interval carcinomas of the proximal colon. Serrated polyposis syndrome is now widely recognized as conferring a high risk of colorectal carcinoma although its cause remains elusive. The current understanding of the actual malignant potential of each serrated polyp subtype is still limited due to the lack of large-scale prospective studies. Patient management guidelines have been recently updated although high-level evidence to support them is still required.

A population-based study of hereditary non-polyposis colorectal cancer: evidence of pathologic and genetic heterogeneity

Hereditary non-polyposis colorectal cancer (HNPCC) may be the result of Lynch syndrome (LS) caused by mutations in mismatch repair (MMR) genes, a syndrome of unknown etiology called familial colorectal cancer type-X (FCCTX), or familial serrated neoplasia associated with the colorectal cancer (CRC) somatic BRAF mutation. To determine the cause of HNPCC in the founder population of the island of Newfoundland, we studied 37 families with LS and 29 families without LS who fulfilled the Amsterdam I criteria. In non-LS, four index CRCs were BRAF mutation positive, one of which was microsatellite instable. Geographic clustering of LS families caused by three different founder mutations in MSH2 was observed. Nine unique MMR mutations in four MMR genes were identified in single families distributed in different geographic isolates. The geographic distribution of non-LS was similar to LS. The coefficient of relatedness using genotype data was significantly higher for non-LS than for all CRC. Extensive genealogic investigation failed to connect non-LS families and in some clusters pathologic CRC heterogeneity was observed. We conclude that non-LS HNPCC may be a heterogeneous disorder with different pathogenic pathways, and that the geographic distribution is consistent with multiple different mutations in unknown CRC susceptibility gene(s).

Cancer risks for relatives of patients with serrated polyposis

OBJECTIVES

Serrated polyposis (hyperplastic polyposis) is characterized by multiple polyps with serrated architecture in the colorectum. Although patients with serrated polyposis are known to be at increased risk of colorectal cancer (CRC) and possibly extracolonic cancers, cancer risk for their relatives has not been widely explored. The aim of this study was to estimate the risks of CRC and extracolonic cancers for relatives of patients with serrated polyposis.

METHODS

A cohort of the 1,639 first- and second-degree relatives of 100 index patients with serrated polyposis recruited regardless of a family history of polyps or cancer from genetic clinics in Australia, New Zealand, Canada, and the USA, were retrospectively analyzed to estimate the country-, age-, and sex-specific standardized incidence ratios (SIRs) for relatives compared with the general population.

RESULTS

A total of 102 CRCs were observed in first- and second-relatives (SIR 2.25, 95% confidence interval (CI) 1.75-2.93; P<0.001), with 54 in first-degree relatives (SIR 5.16, 95% CI 3.70-7.30; P<0.001) and 48 in second-degree relatives (SIR 1.38, 95% CI 1.01-1.91; P=0.04). Six pancreatic cancers were observed in first-degree relatives (SIR 3.64, 95% CI 1.70-9.21; P=0.003). There was no statistical evidence of increased risk for cancer of the stomach, brain, breast, or prostate.

CONCLUSIONS

Our finding that relatives of serrated polyposis patients are at significantly increased risk of colorectal and pancreatic cancer adds to the accumulating evidence that serrated polyposis has an inherited component.

Cancer risks for the relatives of colorectal cancer cases with a methylated MLH1 promoter region: data from the Colorectal Cancer Family Registry

Methylation of the MLH1 gene promoter region is an underlying cause of colorectal cancer (CRC) with high microsatellite instability (MSI-H) diagnosed in persons without a germ line mutation in a mismatch repair (MMR) gene (non-Lynch Syndrome CRC). It is unclear whether relatives of CRC cases with MLH1 methylation have an increased risk of colorectal or other cancers. In this retrospective cohort study, we assessed risk of CRC and other cancers for the first- and second-degree relatives of CRC cases with a methylated MLH1 gene, by comparing observed numbers of cases with those expected on the basis of age-, sex-, and country-specific cancer incidences (standardized incidence ratios). The cohort consisted of 3,128 first- and second-degree relatives of the 233 MLH1-methylated CRC cases with no MMR or MUTYH gene mutations. The standardized incidence ratio (SIR) for CRC was 1.60 [95% confidence interval (CI), 1.22-2.16] for first-degree relatives and 1.08 (0.74-1.60) for second-degree relatives. The SIR for gastric cancer was 2.58 (1.52-4.71) for first-degree relatives and 4.52 (2.23-10.61) for second-degree relatives and, for ovarian cancer, it was 2.16 (1.29-3.86) for first-degree relatives. The risk of liver cancer was also increased significantly in first-degree relatives but the estimate was on the basis of only two cases. These data imply that relatives of CRC cases with MLH1 methylation may be at increased risk of CRC and stomach cancer and possibly ovarian and liver cancer, suggesting that there may be a heritable factor for CRC and other cancers associated with MLH1 methylation in non-Lynch syndrome CRCs.