Genotype-phenotype correlations for pancreatic cancer risk in Dutch melanoma families with pathogenic CDKN2A variants.

BACKGROUND: Pathogenic variants in the CDKN2A gene are generally associated with the development of melanoma and pancreatic ductal adenocarcinoma (PDAC), but specific genotype-phenotype correlations might exist and the extent of PDAC risk is not well established for many variants. METHODS: Using the Dutch national familial melanoma database, we identified all families with a pathogenic CDKN2A variant and investigated the occurrence of PDAC within these families. We also estimated the standardised incidence ratio and lifetime PDAC risk for carriers of a highly prevalent variant in these families. RESULTS: We identified 172 families in which 649 individuals carried 15 different pathogenic variants. The most prevalent variant was the founder mutation c.225_243del (p16-Leiden, 484 proven carriers). Second most prevalent was c.67G>C (55 proven carriers). PDAC developed in 95 of 163 families (58%, including 373 of 629 proven carriers) harbouring a variant with an effect on the p16INK4a protein, whereas PDAC did not occur in the 9 families (20 proven carriers) with a variant affecting only p14ARF. In the c.67G>C families, PDAC occurred in 12 of the 251 (5%) persons at risk. The standardised incidence ratio was 19.1 (95% CI 8.3 to 33.6) and the cumulative PDAC incidence at age 75 years (lifetime risk) was 19% (95% CI 7.5% to 30.1%). CONCLUSIONS: Our results support the notion that pathogenic CDKN2A variants affecting the p16INK4a protein, including c.67G>C, are associated with increased PDAC risk and carriers of such variants should be offered pancreatic cancer surveillance. There is no clinical evidence that impairment of only the p14ARF protein leads to an increased PDAC risk.

An alternative approach to establishing unbiased colorectal cancer risk estimation in Lynch syndrome.

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

The Apparent Genetic Anticipation in PMS2-Associated Lynch Syndrome Families Is Explained by Birth-cohort Effect.

BACKGROUND: PMS2-associated Lynch syndrome is characterized by a relatively low colorectal cancer penetrance compared with other Lynch syndromes. However, age at colorectal cancer diagnosis varies widely, and a strong genetic anticipation effect has been suggested for PMS2 families. In this study, we examined proposed genetic anticipation in a sample of 152 European PMS2 families. METHODS: The 152 families (637 family members) that were eligible for analysis were mainly clinically ascertained via clinical genetics centers. We used weighted Cox-type random effects model, adjusted by birth cohort and sex, to estimate the generational effect on the age of onset of colorectal cancer. Probands and young birth cohorts were excluded from the analyses. Weights represented mutation probabilities based on kinship coefficients, thus avoiding testing bias. RESULTS: Family data across three generations, including 123 colorectal cancers, were analyzed. When compared with the first generation, the crude HR for anticipation was 2.242 [95% confidence interval (CI), 1.162-4.328] for the second generation and 2.644 (95% CI, 1.082-6.464) for the third generation. However, after correction for birth cohort and sex, the effect vanished [HR = 1.302 (95% CI, 0.648-2.619) and HR = 1.074 (95% CI, 0.406-2.842) for second and third generations, respectively]. CONCLUSIONS: Our study did not confirm previous reports of genetic anticipation in PMS2-associated Lynch syndrome. Birth-cohort effect seems the most likely explanation for observed younger colorectal cancer diagnosis in subsequent generations, particularly because there is currently no commonly accepted biological mechanism that could explain genetic anticipation in Lynch syndrome. IMPACT: This new model for studying genetic anticipation provides a standard for rigorous analysis of families with dominantly inherited cancer predisposition.

Cancer Risks for PMS2-Associated Lynch Syndrome.

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.

Ovarian stimulation for IVF and risk of primary breast cancer in BRCA1/2 mutation carriers.

BACKGROUND: The effect of in vitro fertilisation (IVF) on breast cancer risk for BRCA1/2 mutation carriers is rarely examined. As carriers may increasingly undergo IVF as part of preimplantation genetic diagnosis (PGD), we examined the impact of ovarian stimulation for IVF on breast cancer risk in BRCA1/2 mutation carriers. METHODS: The study population consisted of 1550 BRCA1 and 964 BRCA2 mutation carriers, derived from the nationwide HEBON study and the nationwide PGD registry. Questionnaires, clinical records and linkages with the Netherlands Cancer Registry were used to collect data on IVF exposure, risk-reducing surgeries and cancer diagnosis, respectively. Time-dependent Cox regression analyses were conducted, stratified for birth cohort and adjusted for subfertility. RESULTS: Of the 2514 BRCA1/2 mutation carriers, 3% (n = 76) were exposed to ovarian stimulation for IVF. In total, 938 BRCA1/2 mutation carriers (37.3%) were diagnosed with breast cancer. IVF exposure was not associated with risk of breast cancer (HR: 0.79, 95% CI: 0.46-1.36). Similar results were found for the subgroups of subfertile women (n = 232; HR: 0.73, 95% CI: 0.39-1.37) and BRCA1 mutation carriers (HR: 1.12, 95% CI: 0.60-2.09). In addition, age at and recency of first IVF treatment were not associated with breast cancer risk. CONCLUSION: No evidence was found for an association between ovarian stimulation for IVF and breast cancer risk in BRCA1/2 mutation carriers.

Oral Contraceptive Use and Breast Cancer Risk: Retrospective and Prospective Analyses From a BRCA1 and BRCA2 Mutation Carrier Cohort Study.

BACKGROUND: For BRCA1 and BRCA2 mutation carriers, the association between oral contraceptive preparation (OCP) use and breast cancer (BC) risk is still unclear. METHODS: Breast camcer risk associations were estimated from OCP data on 6030 BRCA1 and 3809 BRCA2 mutation carriers using age-dependent Cox regression, stratified by study and birth cohort. Prospective, left-truncated retrospective and full-cohort retrospective analyses were performed. RESULTS: For BRCA1 mutation carriers, OCP use was not associated with BC risk in prospective analyses (hazard ratio [HR] = 1.08, 95% confidence interval [CI] = 0.75 to 1.56), but in the left-truncated and full-cohort retrospective analyses, risks were increased by 26% (95% CI = 6% to 51%) and 39% (95% CI = 23% to 58%), respectively. For BRCA2 mutation carriers, OCP use was associated with BC risk in prospective analyses (HR = 1.75, 95% CI = 1.03 to 2.97), but retrospective analyses were inconsistent (left-truncated: HR = 1.06, 95% CI = 0.85 to 1.33; full cohort: HR = 1.52, 95% CI = 1.28 to 1.81). There was evidence of increasing risk with duration of use, especially before the first full-term pregnancy (BRCA1: both retrospective analyses, P < .001 and P = .001, respectively; BRCA2: full retrospective analysis, P = .002). CONCLUSIONS: Prospective analyses did not show that past use of OCP is associated with an increased BC risk for BRCA1 mutation carriers in young middle-aged women (40-50 years). For BRCA2 mutation carriers, a causal association is also not likely at those ages. Findings between retrospective and prospective analyses were inconsistent and could be due to survival bias or a true association for younger women who were underrepresented in the prospective cohort. Given the uncertain safety of long-term OCP use for BRCA1/2 mutation carriers, indications other than contraception should be avoided and nonhormonal contraceptive methods should be discussed.

SNP association study in PMS2-associated Lynch syndrome.

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

A case series of intestinal adenomatous polyposis of unidentified etiology; a late effect of irradiation?

BACKGROUND: In a large number of patients with multiple gastrointestinal adenomatous polyps, no causal germline mutation can be found. Non-genetic factors may contribute to the development of adenomatous polyps in these unexplained polyposis patients. In the development of gastrointestinal cancer, prior exposure to abdominal radiotherapy has been identified as such a factor, as it increases the gastrointestinal cancer risk in cancer survivors. A relationship of radiotherapy with intestinal polyposis, however, has not yet been described. Despite the increased cancer risk, these cancer survivors do not receive gastrointestinal screening recommendations. This case series describes three patients with adenomatous polyposis after abdominal radiotherapy. CASE PRESENTATION: Patient 1 was diagnosed with testicular cancer at the age of 31 and was treated with hemicastration, radiotherapy and chemotherapy. Thirty-nine years later, he was diagnosed with more than 30 colonic adenomas. Additionally, gastroduodenoscopy revealed a well-differentiated adenocarcinoma in the antrum of the stomach. Patient 2 was diagnosed with a nephroblastoma at the age of 10, which was resected and treated with radiotherapy and chemotherapy. At age 36, a rectal adenocarcinoma was diagnosed and treated by radiotherapy and a total mesorectal excision. During 11 years of surveillance endoscopies, 21 colonic adenomas and three duodenal adenomas were detected. Patient 3 was diagnosed with Hodgkin lymphoma at the age of 20 and treated with radiotherapy, followed by chemotherapy for a recurrence 3 years later. At age 62, a subtotal colectomy was performed because of colonic polyposis: 36 adenomas were detected. During screening gastro-duodenoscopy, three duodenal adenomas were detected. In all three patients, germline analysis did not reveal a mutation in the APC and MYH genes. The gastric and rectal cancer were both microsatellite stable. CONCLUSION: This report describes three patients with adenomatous polyposis, of which two developed a gastrointestinal cancer. The polyposis was not explained by a germline mutation in APC or MYH and all patients received abdominal radiotherapy. Although an etiologic role has not been established, an association between radiotherapy and intestinal adenomatous polyposis and the subsequent development of cancer seems very likely in our patients.

Comprehensive Mutation Analysis of PMS2 in a Large Cohort of Probands Suspected of Lynch Syndrome or Constitutional Mismatch Repair Deficiency Syndrome.

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

Do BRCA1/2 mutation carriers have an earlier onset of natural menopause?

OBJECTIVE: It has been hypothesized that BRCA1/2 mutation carriers have an earlier age at natural menopause (ANM), although to date findings are inconclusive. This study assessed the influence of BRCA mutation status on ANM, and aimed to explore the reasons of inconsistency in the literature. METHODS: Cross-sectional assessment from an ongoing nationwide cohort study among members of BRCA1/2 mutated families. Information was obtained by a standardized questionnaire. Kaplan-Meier curves were constructed, and Cox regression was used to assess the association between BRCA1/2 mutation status and ANM. Adjustments were made for birth cohort, family, smoking, use of hormonal contraceptives, and parity. RESULTS: A total of 1,208 BRCA1/2 mutation carriers and 2,211 proven noncarriers were included. Overall, no association was found between BRCA1/2 mutation status and ANM (adjusted hazard ratio [HR] = 1.06 [95% CI, 0.87-1.30]). We examined if the null finding was due to informative censoring by uptake of risk-reducing salpingo-oophorectomy. Indeed, within the oldest birth cohort, in which the percentage of surgical menopause events was lowest and comparable between carriers and noncarriers, the HR for earlier natural menopause in carriers was 1.45 (95% CI, 1.09-1.94). The second oldest birth cohort, however, demonstrated a decreased HR (0.67 [95% CI, 0.46-0.98]), and thus no trend over birth cohorts was found. CONCLUSIONS: Various types of selection bias hamper the comparison of ANM between BRCA1/2 mutation carriers and noncarriers, genetically tested in the clinic.

The effect of genotypes and parent of origin on cancer risk and age of cancer development in PMS2 mutation carriers.

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

[Hereditary leiomyomatosis: a woman with red-brown nodules]. / Erfelijke leiomyomatose: een vrouw met rood-bruine bultjes.

BACKGROUND: Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is a rare disorder involving multiple organ systems. It is caused by a mutation in the fumarate hydratase (FH) gene. Patients show cutaneous abnormalities or uterine myomas. Approximately 10% of these patients also develop an aggressive type of renal cell carcinoma. CASE DESCRIPTION: A 35-year-old woman was referred by her general practitioner with a number of progressive red-brown nodules on her arms and trunk. A biopsy was taken, revealing cutaneous leiomyoma. On further examination, a small, benign uterine myoma was found. There were no signs of a renal cell carcinoma. Further diagnostic procedures showed a FH mutation, confirming the diagnosis of HLRCC. CONCLUSION: HRLCC is a rare condition that can be missed easily as clinical symptoms are often subtle. Considering the risk of developing an aggressive form of renal cell carcinoma, it is important to screen these patients thoroughly and to follow them up.

Lynch syndrome caused by germline PMS2 mutations: delineating the cancer risk.

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

Yield of screening colonoscopy in first-degree relatives of patients with serrated polyposis syndrome.

GOALS: We aimed to evaluate the diagnostic yield of screening colonoscopies in first-degree relatives (FDRs) of patients with serrated polyposis syndrome (SPS). BACKGROUND: Patients with SPS are at an increased risk for colorectal cancer. Although inheritance patterns are unknown, FDRs of these patients have an increased risk for both colorectal cancer and SPS. Prospective studies evaluating the yield of screening colonoscopies in this group are however scarce. This information would be useful to evaluate a possible mode of inheritance and to investigate whether screening colonoscopies are justified in this group. STUDY: FDR of patients with SPS were invited to undergo colonoscopy. The diagnostic yield was expressed by the number of FDRs with at least 1 significant polyp relative to the total number of included FDRs. Significant polyps were defined adenomas, traditional serrated adenomas, sessile serrated adenoma/polyp, or proximal hyperplastic polyp. Tissue specimens were reviewed by one expert pathologist. RESULTS: Seventy-seven FDRs underwent colonoscopy (median age 52 y; interquartile range, 41 to 60). Colorectal cancer was not diagnosed. One or more significant polyps were detected in 43% of FDRs. No differences based on age, gender, or familial relationship were observed in the detection of polyps. Seven first-degree (9%) relatives had multiple polyps (≥5). Eleven (14%) FDRs fulfilled SPS WHO-criterion 2, of whom 1 sibling also met SPS WHO-criterion 3. CONCLUSIONS: The yield of a single screening colonoscopy in FDRs of patients with serrated polyposis is substantial, warranting a colonoscopy screening program for these individuals.

Variation in mutation spectrum partly explains regional differences in the breast cancer risk of female BRCA mutation carriers in the Netherlands.

BACKGROUND: We aimed to quantify previously observed relatively high cancer risks in BRCA2 mutation carriers (BRCA2 carriers) older than 60 in the Northern Netherlands, and to analyze whether these could be explained by mutation spectrum or population background risk. METHODS: This consecutive cohort study included all known pathogenic BRCA1/2 carriers in the Northern Netherlands (N = 1,050). Carrier and general reference populations were: BRCA1/2 carriers in the rest of the Netherlands (N = 2,013) and the general population in both regions. Regional differences were assessed with HRs and ORs. HRs were adjusted for birth year and mutation spectrum. RESULTS: All BRCA1 carriers and BRCA2 carriers younger than 60 had a significantly lower breast cancer risk in the Northern Netherlands; HRs were 0.66 and 0.64, respectively. Above age 60, the breast cancer risk in BRCA2 carriers in the Northern Netherlands was higher than in the rest of the Netherlands [HR, 3.99; 95% confidence interval (CI), 1.11-14.35]. Adjustment for mutational spectrum changed the HRs for BRCA1, BRCA2 <60, and BRCA2 ≥60 years by -3%, +32%, and +11% to 0.75, 0.50, and 2.61, respectively. There was no difference in background breast cancer incidence between the two regions (OR, 1.03; 95% CI, 0.97-1.09). CONCLUSIONS: Differences in mutation spectrum only partly explain the regional differences in breast cancer risk in BRCA2 carriers, and for an even smaller part in BRCA1 carriers. IMPACT: The increased risk in BRCA2 carriers older than 60 may warrant extension of intensive breast screening beyond age 60.

Extracolonic cancer risk in patients with serrated polyposis syndrome and their first-degree relatives.

Serrated polyposis syndrome is associated with an increased colorectal cancer risk. Although the underlying genetic cause of the condition is unknown, first-degree relatives of patients with serrated polyposis have an increased risk for colorectal cancer compared with the general population. This suggests an inheritable component. Since other hereditary polyposis syndromes are often associated with an expanded extracolonic tumour spectrum, our aim was to determine the extra colonic cancer risks for patients with serrated polyposis and their first-degree relatives and compare these risks with the general population. Serrated polyposis index patients from 5 medical centres were included. Demographic data concerning age, sex and reported malignancies were ascertained by reviewing medical charts and histopathology reports. Family history was obtained by examining pedigree records from the department of Clinical Genetics. Incidence rates of extracolonic malignancies were compared with the general population through a person-year analysis, adjusted for age and sex. Population-based incidence data were derived from the Eindhoven Cancer Registry. A total of 105 patients with serrated polyposis and 341 first-degree relatives were included. Among the patients with serrated polyposis, 9 extracolonic cancers were observed, compared to 13 expected malignancies in the general population (RR 0.69 95% CI 0.36-1.33; p = 0.27). Among the first-degree relatives, 44 extracolonic malignancies were observed, compared to 48 expected malignancies (RR 0.92 95% CI 0.69-1.24; p = 0.60). In this study, the overall incidence of extracolonic malignancies in patients with serrated polyposis and their first-degree relatives was not increased. Large international studies are required to confirm these results.

Risks of less common cancers in proven mutation carriers with lynch syndrome.

PURPOSE: Patients with Lynch syndrome are at high risk for colon and endometrial cancer, but also at an elevated risk for other less common cancers. The purpose of this retrospective cohort study was to provide risk estimates for these less common cancers in proven carriers of pathogenic mutations in the mismatch repair (MMR) genes MLH1, MSH2, and MSH6. PATIENTS AND METHODS: Data were pooled from the German and Dutch national Lynch syndrome registries. Seven different cancer types were analyzed: stomach, small bowel, urinary bladder, other urothelial, breast, ovarian, and prostate cancer. Age-, sex- and MMR gene-specific cumulative risks (CRs) were calculated using the Kaplan-Meier method. Sex-specific incidence rates were compared with general population incidence rates by calculating standardized incidence ratios (SIRs). Multivariate Cox regression analysis was used to estimate the impact of sex and mutated gene on cancer risk. RESULTS: The cohort comprised 2,118 MMR gene mutation carriers (MLH1, n = 806; MSH2, n = 1,004; MSH6, n = 308). All cancers were significantly more frequent than in the general population. The highest risks were found for male small bowel cancer (SIR, 251; 95% CI, 177 to 346; CR at 70 years, 12.0; 95% CI, 5.7 to 18.2). Breast cancer showed an SIR of 1.9 (95% CI, 1.4 to 2.4) and a CR of 14.4 (95% CI, 9.5 to 19.3). MSH2 mutation carriers had a considerably higher risk of developing urothelial cancer than MLH1 or MSH6 carriers. CONCLUSION: The sex- and gene-specific differences of less common cancer risks should be taken into account in cancer surveillance and prevention programs for patients with Lynch syndrome.

Indication for CDKN2A-mutation analysis in familial pancreatic cancer families without melanomas.

BACKGROUND: CDKN2A-mutation carriers run a high risk of developing melanomas and have an increased risk of developing pancreatic cancer (PC). Familial PC (FPC) patients with a personal history or family history of melanomas are therefore offered CDKN2A-mutation analysis. In contrast, CDKN2A testing in FPC families without a history of melanomas is not generally recommended. The aim of this study was to evaluate the frequency of CDKN2A-mutations in FPC families without melanomas. METHODS: Data were gathered from PC family registers. FPC families were defined as families with clustering of PC without meeting diagnostic criteria of familial cutaneous malignant melanoma (familial CMM) or other inherited cancer syndromes. Blood samples were obtained for DNA isolation from PC patients or first degree relatives and analysed for CDKN2A-mutations. RESULTS: Among 40 FPC families, DNA analyses were carried out in 28 families (70%), leading to identification of CDKN2A-mutations in six families (21%). None of the CDKN2A-mutation-positive families fulfilled the diagnostic criteria for familial CMM and in three CDKN2A families no melanomas were observed. Two CDKN2A-mutations were found; the Dutch founder mutation p16-Leiden (c.225_243del, p.Ala76fs) and the c.19_23dup, p.Ser8fs-mutation. After disclosure of the CDKN2A-mutation in one of the families, a curable melanoma was diagnosed at dermatological surveillance in a 17-year-old family member. CONCLUSION: CDKN2A-mutation can be found in a considerable proportion of families with FPC. CDKN2A-mutation analysis should therefore be included in genetic testing in FPC families, even in the absence of reported melanomas. This strategy will enhance the recognition of individuals at risk for PC and facilitate the early detection of melanomas.