Extracolonic cancers associated with hereditary nonpolyposis colorectal cancer in the Utah Population Database

Correlation of mismatch repair deficiency with clinicopathological features and programmed death-ligand 1 expression in thyroid carcinoma

BACKGROUND

Mutations in DNA mismatch repair (MMR) genes associated with thyroid carcinoma (TC) have rarely been reported, especially in East Asian populations.

METHODS

We examined tumor tissue from a cohort of 241 patients diagnosed with TC between 2008 and 2020. MMR proteins were detected using tissue microarray-based immunohistochemistry in order to identify MMR-protein-deficient (MMR-D) and MMR-protein-intact (MMR-I) tumors. We retrospectively summarized the clinicopathologic characteristics of patients with MMR-D TC, measured the expression of PD-L1, and recorded overall survival (OS) and other clinical outcomes.

RESULTS

In our cohort, there were 18 (7.5%) MMR-D (MLH1, MSH2, MSH6, and PMS2) patients, including 12 with papillary TC (PTC) (6.7%), 2 with poorly differentiated TC (PDTC) (4.7%), and 4 with anaplastic TC (ATC) (22.2%). Half of them (9/18) showed a specific deletion in MSH6, and 6 of them also carried variants in the MSH6 and PMS2 gene. Survival was significantly better in patients with MMR-D ATC than in those with MMR-I tumors (p = 0.033). Four of the 18 MMR-D patients (22%) were found to be PD-L1 positive. Their OS was much shorter than that of PD-L1-negative patients.

CONCLUSIONS

MMR-D and PD-L1 positivity appear to be associated with clinicopathological characteristics and prognosis in TC. The results indicate that MMR status may have important prognostic significance in TC. Therefore, immune checkpoint inhibitors that target the PD-1/PD-L1 pathway may be a treatment option for TCs.

Cancer Risk in Families Fulfilling the Amsterdam Criteria for Lynch Syndrome

Importance

The data describing cancer risks associated with Lynch syndrome are variable.

Objectives

To quantify the prevalence of families that fulfill the Amsterdam I or II criteria for Lynch syndrome in the Utah population and investigate the risk of colonic and extracolonic cancers in family members and their relatives.

Design, Setting, and Participants

In a population-based study, 202 families with Amsterdam I and II criteria–positive pedigrees in the Utah Population Database were identified. Of these, all cancer diagnoses in members of families with Amsterdam criteria and their first-degree, second-degree, and first-cousin relatives were located through linkage to the Utah Cancer Registry. The study was conducted from May 1 to June 30, 2016.

Main Outcomes and Measures

Standardized morbidity ratios (SMRs) were estimated by comparing the observed rates of cancer in relatives with population-expected rates estimated internally from the Utah Population Database.

Results

A total of 202 families meeting Amsterdam criteria for Lynch syndrome accounted for 2.6% of all colorectal cancers in the state; of these, 59 met both the Amsterdam I and Amsterdam II criteria. Cancers observed in significant excess in the first-degree relatives of Amsterdam criteria pedigrees included colorectal (SMR, 10.10; 95% CI, 9.43-10.81), endometrial (SMR, 5.89; 95% CI, 5.09-6.78), stomach (SMR, 2.90; 95% CI, 2.02-4.03), small intestine (SMR, 7.72; 95% CI, 5.17-11.08), prostate (SMR, 1.94; 95% CI, 1.73-2.17), kidney (SMR, 3.22; 95% CI, 2.45-4.16), urinary bladder (SMR, 1.62; 95% CI, 1.22-2.12), thyroid (SMR, 2.26; 95% CI, 1.55-3.17), and non-Hodgkin lymphoma (SMR, 2.10; 95% CI, 1.64-2.65). Risks of colorectal and endometrial cancers were also found to be elevated in second-degree (SMR, 4.31; 95% CI, 3.98-4.65 and SMR, 2.70; 95% CI, 2.30-3.14, respectively) and first-cousin (SMR, 1.85; 95% CI, 1.70-2.00 and SMR, 1.50; 95% CI, 1.29-1.73, respectively) relatives of families with Amsterdam criteria.

Conclusions and Relevance

In this population-based study of cancer risk in families fulfilling the Amsterdam criteria, many of the cancers previously reported to be associated with Lynch syndrome were observed, several previously unreported cancer associations were noted, and the risk of colorectal and endometrial cancer were markedly increased in first-, second-, and even third-degree relatives of these families. This study provides clinicians with population-based, unbiased data to counsel members of families meeting the Amsterdam criteria regarding their elevated risks of cancer and the importance of cancer screening.

Epidemioclinical Feature of Early-Onset Colorectal Cancer at-Risk for Lynch Syndrome in Central Iran

BACKGROUND

Colorectal cancer (CRC) is becoming one of the most complicated challenges of human health, particularly in developing countries like Iran. In this paper, we try to characterize CRC cases diagnosed < age 50 at-risk for Lynch syndrome within central Iran.

MATERIALS AND METHODS

We designed a descriptive retrospective study to screen all registered CRC patients within 2000-2013 in Poursina Hakim Research Center (PHRC), a referral gastroenterology clinic in central Iran, based on being early-onset (age at diagnosis ≤50 years) and Amsterdam II criteria. We calculated frequencies and percentages by SPSS 19 software to describe clinical and family history characteristics of patients with early-onset CRC.

RESULTS

Overall 1,659 CRC patients were included in our study of which 413 (24.9%) were ≤50 years at diagnosis. Of 219/413 successful calls 67 persons (30.6%) were reported deceased. Family history was positive for 72/219 probands (32.9%) and 53 families (24.2%) were identified as familial colorectal cancer (FCC), with a history of at-least three affected members with any type of cancer in the family, of which 85% fulfilled the Amsterdam II Criteria as hereditary non-polyposis colorectal cancer (HNPCC) families (45/219 or 20.5%). Finally, 14 families were excluded due to proband tumor tissues being unavailable or unwillingness for incorporation. The most common HNPCC-associated extracolonic- cancer among both males and females of the families was stomach, at respectively 31.8 and 32.7 percent. The most common tumor locations among the 31 probands were rectum (32.3%), sigmoid (29.0%), and ascending colon (12.9%).

CONCLUSIONS

Given the high prevalence of FCC (~1/4 of early-onset Iranian CRC patients), it is necessary to establish a comprehensive cancer genetic counseling and systematic screening program for early detection and to improve cancer prognosis among high risk families.

Equivalent Helicobacter pylori infection rates in Lynch syndrome mutation carriers with and without a first-degree relative with gastric cancer

BACKGROUND

Patients with Lynch syndrome (LS) are at an increased risk of developing gastric cancer. In 2010, a guideline that recommended to screen all patients for Helicobacter pylori was implemented in the Netherlands. H. pylori is an important risk factor in the development of gastric cancer in the general population, and eradication of the bacterium reduces this risk. We aimed to assess the proportion of LS patients being tested and the yield and also addressed the question whether H. pylori infection is more prevalent in LS families with known cases of gastric cancer.

METHODS

Proven mutation carriers from five different Dutch hospitals were included. The implementation of H. pylori screening and its outcome was examined. The observation period was 2008-2013. The presence of first-degree family members with gastric cancer was noted, and it was observed if H. pylori infection was more prevalent in Lynch families with known cases of gastric cancer. Obtainable endoscopy reports were reviewed.

RESULTS

Four hundred forty-three (male, 184) proven mutation carriers were included. The proportion of patients screened increased after 2010, from 37 to 68%. Twenty percent of the patients were infected. The 25 patients who had a first-degree family member with gastric cancer did not have a higher infection rate. In 30% of cases, an endoscopy was performed; in four patients, intestinal metaplasia and in eight patients, gastric cancer was found.

CONCLUSION

The recommendation to screen for H. pylori is increasingly followed. The prevalence of infection in this patient group does not differ from the general population. Patients who had a first-degree family member with gastric cancer did not have a higher infection rate.

Risk of prostate cancer in Lynch syndrome: a systematic review and meta-analysis

It has been controversial that men carrying a DNA mismatch repair (MMR) gene mutation (Lynch syndrome) are at heightened risk of prostate cancer given that an increased risk is likely to be modest and the prevalence of prostate cancer is high. We used PubMed to search for "molecular studies" that reported MMR-deficiency status of prostate cancer tumors in men with an MMR gene mutation, and "risk studies" that reported prostate cancer risk for men known or suspected to have an MMR gene mutation relative to that for noncarriers or the general population. Of the six molecular studies, 32 of 44 [73%, 95% confidence intervals (CI), 57%-85%] prostate cancer tumors in carriers were MMR deficient, which equates to carriers having a 3.67-fold increased risk of prostate cancer (95% CI, 2.32-6.67). Of the 12 risk studies, we estimated a 2.13-fold increased risk of prostate cancer (95% CI, 1.45-2.80) for male carriers in clinic-based retrospective cohorts, 2.11 (95% CI, 1.27-2.95) for male carriers with a prior diagnosis of colorectal cancer, and 2.28 (95% CI, 1.37-3.19) for all men from mutation-carrying families. The combination of evidence from molecular and risk studies in the current literature supports consideration of prostate cancer as part of Lynch syndrome.

Elevated risk of prostate cancer among men with Lynch syndrome

PURPOSE

Prostate cancer has been described as a component tumor of Lynch syndrome (LS), with tumors obtained from mutation carriers demonstrating the DNA mismatch repair deficiency phenotype. Previous studies quantifying prostate cancer risk in LS have provided conflicting results.

METHODS

We examined cancer histories of probands and their first- through fourth-degree relatives for 198 independent mutation-positive LS families enrolled in two US familial cancer registries. Modified segregation analysis was used to calculate age-specific cumulative risk or penetrance estimates, with accompanying Wald-type CIs. Cumulative lifetime risks and hazard ratio (HR) estimates for prostate cancer were calculated and compared with those of the general population.

RESULTS

Ninety-seven cases of prostate cancer were observed in 4,127 men. Median age at prostate cancer diagnosis was 65 years (range, 38 to 89 years), with 11.53% of affected individuals diagnosed before age 50 years. The cumulative risk of prostate cancer at ages 60 and 80 years was 6.30% (95% CI, 2.47 to 9.96) and 30.0% (95% CI, 16.54 to 41.30), as compared with the population risk of 2.59% and 17.84%, respectively. The overall prostate cancer HR among carriers was 1.99 (95% CI, 1.31 to 3.03).

CONCLUSION

The cumulative lifetime risk of prostate cancer in individuals with LS is two-fold higher than in the general population and is slightly higher in carriers diagnosed before age 60 years (HR, 2.48; 95% CI, 1.34 to 4.59). These estimates are clinically valuable to quantify risk for both patients and providers.

How well does family history predict who will get colorectal cancer? Implications for cancer screening and counseling

PURPOSE

Using a large, retrospective cohort from the Utah Population Database, we assess how well family history predicts who will acquire colorectal cancer during a 20-year period.

METHODS

Individuals were selected between ages 35 and 80 with no prior record of colorectal cancer diagnosis, as of the year 1985. Numbers of colorectal cancer-affected relatives and diagnosis ages were collected. Familial relative risk and absolute risk estimates were calculated. Colorectal cancer diagnoses in the cohort were counted between years 1986 and 2005. Cox regression and Harrell's C were used to measure the discriminatory power of resulting models.

RESULTS

A total of 431,153 individuals were included with 5,334 colorectal cancer diagnoses. Familial relative risk ranged from 0.83 to 12.39 and 20-year absolute risk from 0.002 to 0.21. With familial relative risk as the only predictor, Harrell's C = 0.53 and with age only, Harrell's C = 0.66. Familial relative risk combined with age produced a Harrell's C = 0.67.

CONCLUSION

Family history by itself is not a strong predictor of exactly who will acquire colorectal cancer within 20 years. However, stratification of risk using absolute risk probabilities may be more helpful in focusing screening on individuals who are more likely to develop the disease.

DNA mismatch repair and infertility

PURPOSE OF REVIEW

To highlight the significance of the abnormal DNA repair mechanism in male infertility.

RECENT FINDINGS

DNA repair defects cause a variety of spermatogenic defects in mouse models. Evidence is accumulating to demonstrate the importance of DNA repair defects in human nonobstructive azoospermia. Epigenetic changes may also play a crucial role in infertility.

SUMMARY

The DNA in the cell needs to be constantly repaired to ensure fidelity of DNA replication, to maintain genome stability and to ensure propagation of species. The DNA repair and recombination machineries are highly conserved across the species and inactivation of these pathways may lead to replication and recombination errors. This review summarizes the different types of DNA lesions and DNA repair pathways, particularly focusing on highly conserved meiotic regulators, the DNA mismatch repair proteins. Targeted deletions of some of these proteins result in infertility and predisposes to tumor in mutant mouse models. There is evidence for loss of some of these proteins in human male infertility. Because defective DNA repair is associated with a mutator phenotype, the risk of transmission to the offspring of these otherwise infertile men conceived using an assisted reproductive technology needs further evaluation.

Risk of urothelial bladder cancer in Lynch syndrome is increased, in particular among MSH2 mutation carriers

Background

Colorectal, endometrial and upper urinary tract tumours are characteristic for Lynch syndrome (hereditary non-polyposis colon carcinoma, HNPCC). The aim of the present study was to establish whether carriers of mutations in mismatch repair genes MLH1, MSH2 or MSH6 are at increased risk of urinary bladder cancer.

Methods

Carriers and first degree relatives of 95 families with a germline mutation in the MLH1 (n=26), MSH2 (n=43), or MSH6 (n=26) gene were systematically questioned about the occurrence of carcinoma. The cumulative risk of cancer occurring before the age of 70 years (CR70) was compared to the CR70 of the general Dutch population. Microsatellite instability (MSI) testing and/or immunohistochemistry (IHC) for mismatch repair proteins was performed on bladder tumour tissue.

Results

Bladder cancer was diagnosed in 21 patients (90% men) from 19 Lynch syndrome families (2 MLH1, 15 MSH2, and 4 MSH6). CR70 for bladder cancer was 7.5% (95% CI 3.1% to 11.9%) for men and 1.0% (95% CI 0% to 2.4%) for women, resulting in relative risks for mutation carriers and first degree relatives of 4.2 (95% CI 2.2 to 7.2) for men and 2.2 (95% CI 0.3 to 8.0) for women. Men carrying an MSH2 mutation and their first degree relatives were at highest risks: CR70 for bladder and upper urinary tract cancer being 12.3% (95% CI 4.3% to 20.3%) and 5.9% (95% CI 0.7% to 11.1%). Bladder cancer tissue was MSI positive in 6/7 tumours and loss of IHC staining was found in 14/17 tumours, indicating Lynch syndrome aetiology.

Conclusion

Patients with Lynch syndrome carrying an MSH2 mutation are at increased risk of urinary tract cancer including bladder cancer. In these cases surveillance should be considered.

Population-based family history-specific risks for colorectal cancer: a constellation approach

BACKGROUND & AIMS

Colorectal cancer (CRC) risk estimates based on family history typically include only close relatives. We report familial relative risk (FRR) in probands with various combinations, or constellations, of affected relatives, extending to third-degree.

METHODS

A population-based resource that includes a computerized genealogy linked to statewide cancer records was used to identify genetic relationships among CRC cases and their first-, second-, and third-degree relatives (FDRs, SDRs, and TDRs). FRRs were estimated by comparing the observed number of affected persons with a particular family history constellation to the expected number, based on cohort-specific CRC rates.

RESULTS

A total of 2,327,327 persons included in > or =3 generation family histories were analyzed; 10,556 had a diagnosis of CRC. The FRR for CRC in persons with > or =1 affected FDR = 2.05 (95% CI, 1.96-2.14), consistent with published estimates. In the absence of a positive first-degree family history, considering both affected SDRs and TDRs, only 1 constellation had an FRR estimate that was significantly >1.0 (0 affected FDRs, 1 affected SDR, 2 affected TDRs; FRR = 1.33; 95% CI, 1.13-1.55). The FRR for persons with 1 affected FDR, 1 affected SDR, and 0 affected TDRs was 1.88 (95% CI, 1.59-2.20), increasing to FRR = 3.28 (95% CI, 2.44-4.31) for probands with 1 affected FDR, 1 affected SDR, and > or =3 affected TDRs.

CONCLUSIONS

Increased numbers of affected FDRs influences risk much more than affected SDRs or TDRs. However, when combined with a positive first-degree family history, a positive second- and third-degree family history can significantly increase risk.

Risk and epidemiological time trends of gastric cancer in Lynch syndrome carriers in the Netherlands

BACKGROUND & AIMS

Although gastric cancer forms part of the Lynch syndrome tumor spectrum, the risk of developing gastric cancer in Lynch syndrome families is unknown, resulting in a lack of clear guidelines for surveillance. The aim of this study was to evaluate incidence trends and risk of developing gastric cancer among Lynch syndrome mutation carriers in a Western population.

METHODS

Lynch syndrome mutation carriers were selected from the Dutch Hereditary Cancer Registry. The gastric cancer incidence in Lynch syndrome mutation carriers was compared to the gastric cancer incidence in the Dutch population between 1970 and 2003. Standardized incidence ratios were calculated by a Poisson model. Cumulative risks were calculated by Kaplan-Meier analysis.

RESULTS

Overall, 2014 Lynch syndrome mutation carriers were identified. Gastric cancer was diagnosed in 32 (1.6%) subjects (male/female: 21/11), 22 (69%) of them had a negative family history of gastric cancer. The standardized incidence ratios of gastric cancer was 3.4 (95% confidence interval, 2.1-5.2) and showed a nonsignificant decline between 1970 and 2003 (P = .30). Absolute risk of developing gastric cancer also showed no significant change over time (P = .51). Lifetime risk of developing gastric cancer was 8.0% in males vs 5.3% in females (P = .02), and 4.8% and 9% for MLH1 and MSH2 carriers, respectively. None of the 378 MSH6 carriers developed gastric cancer (P = .002 vs MLH1 and MSH2 combined lifetime risk).

CONCLUSIONS

Lynch syndrome mutation carriers have a substantial risk for gastric cancer, in particular patients with an MLH1 or MSH2 mutation. Family history for gastric cancer is a poor indicator for individual risk. Surveillance gastroscopy for Lynch syndrome patients carrying an MLH1 or MSH2 mutation should therefore be considered.

Evaluating the informatics for integrating biology and the bedside system for clinical research

Background

Selecting patient cohorts is a critical, iterative, and often time-consuming aspect of studies involving human subjects; informatics tools for helping streamline the process have been identified as important infrastructure components for enabling clinical and translational research. We describe the evaluation of a free and open source cohort selection tool from the Informatics for Integrating Biology and the Bedside (i2b2) group: the i2b2 hive.

Methods

Our evaluation included the usability and functionality of the i2b2 hive using several real world examples of research data requests received electronically at the University of Utah Health Sciences Center between 2006 - 2008. The hive server component and the visual query tool application were evaluated for their suitability as a cohort selection tool on the basis of the types of data elements requested, as well as the effort required to fulfill each research data request using the i2b2 hive alone.

Results

We found the i2b2 hive to be suitable for obtaining estimates of cohort sizes and generating research cohorts based on simple inclusion/exclusion criteria, which consisted of about 44% of the clinical research data requests sampled at our institution. Data requests that relied on post-coordinated clinical concepts, aggregate values of clinical findings, or temporal conditions in their inclusion/exclusion criteria could not be fulfilled using the i2b2 hive alone, and required one or more intermediate data steps in the form of pre- or post-processing, modifications to the hive metadata, etc.

Conclusion

The i2b2 hive was found to be a useful cohort-selection tool for fulfilling common types of requests for research data, and especially in the estimation of initial cohort sizes. For another institution that might want to use the i2b2 hive for clinical research, we recommend that the institution would need to have structured, coded clinical data and metadata available that can be transformed to fit the logical data models of the i2b2 hive, strategies for extracting relevant clinical data from source systems, and the ability to perform substantial pre- and post-processing of these data.

Management of extracolonic tumours in patients with Lynch syndrome

Hereditary nonpolyposis colorectal cancer, or Lynch syndrome, is responsible for 2-3% of all colorectal cancers. Lynch syndrome is also associated with a high risk of extracolonic cancers, including endometrial, stomach, small bowel, pancreas, biliary tract, ovary, urinary tract, brain, and skin cancer. In this Review, we discuss the risks, surveillance tests, and guidelines for the management of extracolonic tumours associated with Lynch syndrome. For all types of extracolonic cancer, evidence supporting surveillance is scarce. A benefit of surveillance is evident only for endometrial cancer, where transvaginal ultrasound and endometrial sampling detect tumours in early stages. Surveillance is generally recommended for urinary tract and gastric cancer, especially in families with more than one member with these types of cancer. For the other types of cancer, surveillance is typically not recommended. Prophylactic hysterectomy and bilateral salpingo-oophorectomy should be considered for women with Lynch syndrome who are past childbearing age, especially during surgery for colorectal cancer. No data show efficacy of chemopreventive drugs in reducing the risk of extracolonic cancers for patients with Lynch syndrome.

Population structure and inbreeding from pedigree analysis of purebred dogs

Dogs are of increasing interest as models for human diseases, and many canine population-association studies are beginning to emerge. The choice of breeds for such studies should be informed by a knowledge of factors such as inbreeding, genetic diversity, and population structure, which are likely to depend on breed-specific selective breeding patterns. To address the lack of such studies we have exploited one of the world's most extensive resources for canine population-genetics studies: the United Kingdom (UK) Kennel Club registration database. We chose 10 representative breeds and analyzed their pedigrees since electronic records were established around 1970, corresponding to about eight generations before present. We find extremely inbred dogs in each breed except the greyhound and estimate an inbreeding effective population size between 40 and 80 for all but 2 breeds. For all but 3 breeds, >90% of unique genetic variants are lost over six generations, indicating a dramatic effect of breeding patterns on genetic diversity. We introduce a novel index Psi for measuring population structure directly from the pedigree and use it to identify subpopulations in several breeds. As well as informing the design of canine population genetics studies, our results have implications for breeding practices to enhance canine welfare.

Upper urinary tract urothelial cell carcinomas and other urological malignancies involved in the hereditary nonpolyposis colorectal cancer (lynch syndrome) tumor spectrum

CONTEXT

The data describing the urologic extracolonic cancers associated with hereditary nonpolyposis colorectal cancer (HNPCC) are variable.

OBJECTIVE

Provide an update about the current urologic tumor spectrum in HNPCC.

EVIDENCE ACQUISITION

Data on HNPCC extracolonic tumor spectrum published in the literature were analysed using MEDLINE with emphasis on urological malignancies, upper tract tumors, clinical criteria, genetic diagnosis and counselling.

EVIDENCE SYNTHESIS

HNPCC is a form of colorectal cancer with a dominant autosomal mode of inheritance. HNPCC is caused by germ-line mutations affecting one or several mismatch repair genes. Cancers other than colorectal cancer are sometimes associated with HNPCC. These include specific urological malignancies, most notably tumors of the upper urinary tract, which have been reported to occur at a rate x22 higher than the general population. Upper urinary tract tumors rank third (5%) after colon (63%) and endometrial (9%) cancer within the group of HNPCC related tumors. Prostate cancer and testicular germ cell tumors are rarely associated. Due to lack of appreciation of such hereditary associations, some inherited cancers are still misclassified as sporadic and their incidence is underestimated. The biological tests requested in suspected cases of HNPCC are: microsatellite instability (MSI) analysis, immunohistochemistry and DNA sequencing. When gene mutations are detected, the patient and their family will benefit from a multidisciplinary management approach. The presence of other HNPCC-associated cancers is sought and close monitoring of patients is undertaken. Genetic counselling is provided to the patient's family.

CONCLUSIONS

The recognized urologic tumor spectrum in HNPCC includes upper tract tumors. However, in order not to overlook a hereditary cancer, urologists should be aware of the possible urological malignancies associated with HNPCC (i.e., prostate and testicular carcinomas) and evaluate appropriately anyone they feel are at high risk of underlying HNPCC based on set clinical criteria.

Syndromic colon cancer: lynch syndrome and familial adenomatous polyposis

Colon cancer, the third leading cause of mortality from cancer in the United States, afflicts about 150,000 patients annually. More than 10% of these patients exhibit familial clustering. The most common and well characterized of these familial colon cancer syndromes is hereditary nonpolyposis colon cancer syndrome (Lynch syndrome), which accounts for about 2% to 3% of all cases of colon cancer in the United States. We review the current knowledge of familial cancer syndromes, with an emphasis on Lynch syndrome and familial adenomatous polyposis.

Gene-related cancer spectrum in families with hereditary non-polyposis colorectal cancer (HNPCC)

The family histories of 130 individuals with documented hereditary non-polyposis colorectal cancer (HNPCC) (caused by mutations in mismatch-repair (MMR) genes MSH2 (n = 64), MLH1 (n = 62) or MSH6 (n = 4)) were obtained, and incidence of cancers in those families was compared to that in the general population. There were a total of 982 cancers in 723 individuals. Colorectal cancer (CRC) was the commonest type (64% and 55% in individuals from families with germline MLH1 and MSH2 mutations respectively). Median age at diagnosis of first CRC in MSH6 mutation families was 59 years compared to 45 years in both MLH1 and MSH2 mutation families. The relative risk (RR) of endometrial cancer was 55 in MSH2 mutation families, compared with 27 in MLH1 mutation families, and 37 in MSH6 mutation families; median age at diagnosis 49 years. Even within MSH2 families, endometrial cancer tended to cluster, with 28 of the 58 cases coming from families with three or more cases (P < 0.001). Absolute risk of endometrial cancer in MLH1 families was still greater than any other cancer (other than CRC). 5% of cancers in both MLH1 and MSH2 mutation families were gastric (RR = 12); 53% of these were diagnosed before 50 years. Seven cases of small intestinal cancer occurred in MSH2 and MLH1 mutation families (RR = 26). There were 13 cases of cancer of the ureter; all were in MSH2 families. These cancers tended to cluster within families (P < 0.001); three of seven families with urothelial cancer had such cases in two or more individuals; two others had kidney cancer. Nineteen of 27 ovarian cancers (70%) were in MSH2 mutation families and 70% of these were diagnosed before age 50 years. There were 9 cases of sebaceous skin cancer, 3 in two MLH1 and 6 in four MSH2 mutation families. Of 22 pancreatic cancers, 14 were known to be diagnosed before 60 years. Breast cancer RR was 1.7 overall. The type of mutation (truncating or other type, and site of mutation) showed no obvious correlation with the presence or absence of extra-colonic cancers in families.

MYH mutations are rare in prostate cancer

PURPOSE

Oxidative stress is considered a risk factor for prostate cancer development and is associated with the production of reactive oxygen species (ROS). The base excision repair gene MYH protects against ROS-mediated damage to DNA. Inherited MYH mutations predispose to colorectal adenomas and cancer. A compromised base-excision repair function due to defective MYH may contribute to prostate carcinogenesis. Here, we examine the genetic contribution of MYH to prostate cancer risk.

METHODS

Patients diagnosed with high-grade prostatic intraepithelial neoplasia (HGPIN) alone (n = 45), prostate cancer alone (n = 123) or both (n = 82) were screened for the two most common mutations in the MYH gene using PCR-based RFLP analysis. A single patient with an inherited MYH mutation as well as a subset of 26 patients presenting with a family history of colorectal cancer were screened for additional MYH mutations by direct sequencing of the entire coding region.

RESULTS

Biallelic germline mutations in MYH were not detected among prostate cancer patients. Only a single patient was a heterozygous carrier for the Y165C missense mutation. Allelic deletion or somatic mutation of the remaining MYH allele was not identified in this patient's tumor DNA. Two patients harbored V22M polymorphism and three patients were carriers of Q324H polymorphism.

CONCLUSIONS

MYH mutations are unlikely to contribute to prostate cancer risk.