Clinicopathologic Characteristics of Endometrial Cancer in Lynch Syndrome: A French Multicenter Study.

BACKGROUND: Limited data exist on Lynch syndrome (LS)-related endometrial cancer (EC) features. Amsterdam criteria II, commonly used, have poor sensitivity for detection of LS, which is underdiagnosed. AIM: The aim of this study was to describe the clinical and pathological features of LS-related EC among mutation-proven patients. METHODS: We conducted a retrospective study from 1977 to 2013 in 5 hospitals. The inclusion criteria were patients who had a primary EC associated to LS proven by a germline mutation. We analyzed the clinical data and the pathology of the tumors. The patient management and the survival data were also collected. RESULTS: Forty-nine patients (15 MLH1, 20 MSH2, 13 MSH6, 1 PMS2) were included. The mean age at diagnosis was 49.7 (SD, 10.5) years. The median body mass index was 22.6 kg/m. In 81.4% of cases, EC was the first cancer of the LS spectrum to occur. Endometrioid adenocarcinoma accounted for 89.2% of the EC, the lower uterine segment was involved in 25% of cases, and a synchronous ovarian cancer was present in 21.6% of patients. The tumors were grade 3 in 19.3% of cases and FIGO (International Federation of Gynecology and Obstetrics) stage I in 66.6% of cases. With a median follow-up of 58 months, 3 patients with conservative management developed a recurrence, and no patient died of EC. CONCLUSIONS: The LS-associated EC is characterized by a young age at onset, a high prevalence of lower uterine segment involvement, and synchronous ovarian cancers. The prognosis of these cancers does not appear different from sporadic tumors.

Diagnosis of Constitutional Mismatch Repair-Deficiency Syndrome Based on Microsatellite Instability and Lymphocyte Tolerance to Methylating Agents.

BACKGROUND & AIMS: Patients with bi-allelic germline mutations in mismatch repair (MMR) genes (MLH1, MSH2, MSH6, or PMS2) develop a rare but severe variant of Lynch syndrome called constitutional MMR deficiency (CMMRD). This syndrome is characterized by early-onset colorectal cancers, lymphomas or leukemias, and brain tumors. There is no satisfactory method for diagnosis of CMMRD because screens for mutations in MMR genes are noninformative for 30% of patients. MMR-deficient cancer cells are resistant to genotoxic agents and have microsatellite instability (MSI), due to accumulation of errors in repetitive DNA sequences. We investigated whether these features could be used to identify patients with CMMRD. METHODS: We examined MSI by PCR analysis and tolerance to methylating or thiopurine agents (functional characteristics of MMR-deficient tumor cells) in lymphoblastoid cells (LCs) from 3 patients with CMMRD and 5 individuals with MMR-proficient LCs (controls). Using these assays, we defined experimental parameters that allowed discrimination of a series of 14 patients with CMMRD from 52 controls (training set). We then used the same parameters to assess 23 patients with clinical but not genetic features of CMMRD. RESULTS: In the training set, we identified parameters, based on MSI and LC tolerance to methylation, that detected patients with CMMRD vs controls with 100% sensitivity and 100% specificity. Among 23 patients suspected of having CMMRD, 6 had MSI and LC tolerance to methylation (CMMRD highly probable), 15 had neither MSI nor LC tolerance to methylation (unlikely to have CMMRD), and 2 were considered doubtful for CMMRD based on having only 1 of the 2 features. CONCLUSION: The presence of MSI and tolerance to methylation in LCs identified patients with CMMRD with 100% sensitivity and specificity. These features could be used in diagnosis of patients.

CDH1 germline mutations and the hereditary diffuse gastric and lobular breast cancer syndrome: a multicentre study.

INTRODUCTION: CDH1 predisposes primarily to diffuse gastric cancer (DGC). Multiple DGC cases in a family, DGC at a young age in an individual or the combination of DGC andlobular breast cancer (LBC) in an individual or a family define the hereditary DGC syndrome (HDGC), and testing for germline CDH1 mutations is warranted in HDGC. METHODS AND RESULTS: We report all index cases from Ile-de-France in which a germline CDH1 mutation has been identified. Out of 18 cases, 7 do not fulfil the HDGC-defining criteria. Three of them are women who presented initially with bilateral LBC below age 50, without personal or family history of DGC, and who subsequently developed symptomatic DGC. DISCUSSION: Our series of CDH1 mutation carriers is the largest to date and demonstrates that LBC might be the first manifestation of HDGC. A personal or family history of multiple LBCs at a young age, even without DGC, should prompt CDH1 mutation screening. It is paramount to identify mutation carriers early, so that they can benefit from prophylactic gastrectomy before they develop symptomatic, highly lethal DGC. We recommend a revision of the HDGC-defining criteria and propose for consideration the name 'Hereditary Diffuse Gastric and Lobular Breast Cancer' instead of HDGC.

Cancer risks associated with germline mutations in MLH1, MSH2, and MSH6 genes in Lynch syndrome.

CONTEXT: Providing accurate estimates of cancer risks is a major challenge in the clinical management of Lynch syndrome. OBJECTIVE: To estimate the age-specific cumulative risks of developing various tumors using a large series of families with mutations of the MLH1, MSH2, and MSH6 genes. DESIGN, SETTING, AND PARTICIPANTS: Families with Lynch syndrome enrolled between January 1, 2006, and December 31, 2009, from 40 French cancer genetics clinics participating in the ERISCAM (Estimation des Risques de Cancer chez les porteurs de mutation des gènes MMR) study; 537 families with segregating mutated genes (248 with MLH1; 256 with MSH2; and 33 with MSH6) were analyzed. MAIN OUTCOME MEASURE: Age-specific cumulative cancer risks estimated using the genotype restricted likelihood (GRL) method accounting for ascertainment bias. RESULTS: Significant differences in estimated cumulative cancer risk were found between the 3 mutated genes (P = .01). The estimated cumulative risks of colorectal cancer by age 70 years were 41% (95% confidence intervals [CI], 25%-70%) for MLH1 mutation carriers, 48% (95% CI, 30%-77%) for MSH2, and 12% (95% CI, 8%-22%) for MSH6. For endometrial cancer, corresponding risks were 54% (95% CI, 20%-80%), 21% (95% CI, 8%-77%), and 16% (95% CI, 8%-32%). For ovarian cancer, they were 20% (95% CI, 1%-65%), 24% (95% CI, 3%-52%), and 1% (95% CI, 0%-3%). The estimated cumulative risks by age 40 years did not exceed 2% (95% CI, 0%-7%) for endometrial cancer nor 1% (95% CI, 0%-3%) for ovarian cancer, irrespective of the gene. The estimated lifetime risks for other tumor types did not exceed 3% with any of the gene mutations. CONCLUSIONS: MSH6 mutations are associated with markedly lower cancer risks than MLH1 or MSH2 mutations. Lifetime ovarian and endometrial cancer risks associated with MLH1 or MSH2 mutations were high but do not increase appreciably until after the age of 40 years.

Role of bax mutations in apoptosis in colorectal cancers with microsatellite instability.

Half of colorectal tumors with microsatellite instability contain frameshift mutations in the (G)8 tract of bax, a major apoptosis effector, but their functional significance remains unclear. We studied the role of bax mutations on bax expression and apoptosis in 59 primary colorectal cancers of which 41 were microsatellite unstable. Tumors were screened for bax(G)8 mutations and evaluated immunohistochemically for bax, bcl-2, and p53 protein expression and apoptotic (M30 cytoDEATH) and proliferative (Ki-67) indexes. We identified bax(G)8 mutations in 20 (49%) of 41 unstable tumors; the mutations were associated significantly with proximal, poorly differentiated, or mucinous adenocarcinomas. Most bax-mutated cases displayed a bax-immunonegative zone in all or part of the tumor that was proved to correspond to biallelic bax(G)8 mutations by microdissection and to confer growth advantage to the tumor by decreasing apoptosis compared with adjacent bax-immunopositive tumor. Biallelic bax(G)8 mutations are subject to positive selection pressure and might disable apoptosis in colorectal cancer.

An appendix carcinoid tumor in a patient with hereditary nonpolyposis colorectal cancer.

Gastrointestinal carcinoid tumors are often associated with other tumors, particularly colon adenocarcinomas; but the association between carcinoid tumors and hereditary nonpolyposis colorectal cancer (HNPCC) syndrome has not yet been explored. We report an unusual case of a 28-year-old woman with HNPCC who underwent surgery for a transverse colon adenocarcinoma in whom an appendix carcinoid tumor was incidentally found. To assess whether the carcinoid tumor displayed the characteristic molecular features of HNPCC tumors, we investigated the expression of mismatch-repair (MMR) proteins and microsatellite instability (MSI) status in both tumors. Both tumors demonstrated normal expression of the MMR proteins hMLH1, hMSH2, hMSH6, and hPMS2. Interestingly, the adenocarcinoma exhibited an MSI phenotype but the carcinoid tumor did not, indicating that these 2 tumors arose through different molecular pathways.

[Identification and management of HNPCC syndrome (hereditary non polyposis colon cancer), hereditary predisposition to colorectal and endometrial adenocarcinomas]. / Identification et prise en charge du syndrome HNPCC (hereditary non polyposis colon cancer), prédisposition héréditaire aux cancers du côlon, du rectum et de l'utérus.

BACKGROUND: The HNPCC syndrome (hereditary non polyposis colon cancer) is an inherited condition defined by clinical and genealogical information, known as Amsterdam criteria. In about 70% of cases, HNPCC syndrome is caused by germline mutations in MMR genes, leading to microsatellite instability of tumor DNA (MSI phenotype). Patients affected by the disease are at high risk for colorectal and endometrial carcinomas, but also for small intestine, urothelial, ovary, stomach and biliary tract carcinomas. HNPCC syndrome is responsible for 5% of colorectal cancers. Identification and management of this disease are part of a multidisciplinary procedure. METHODS: 12 experts have been mandated by the French Health Ministry to analyze and synthesize their consensus position, and the resulting document has been reviewed by an additional group of 4 independent experts. MAIN RECOMMENDATIONS: The lack of sensitivity of Amsterdam criteria in recognizing patients carrying a MMR germline mutation led to an enlargement of these criteria for the recruitment of possible HNPCC patients, and to a 2-steps strategy, asking first for a tumor characterization according to MSI phenotype, especially in case of early-onset sporadic cases. The identification of germline MMR mutations has no major consequence on the cancer treatments, but influences markedly the long-term follow-up and the management of at-risk relatives. Gene carriers will enter a follow-up program regarding their colorectal and endometrial cancer risks, but other organs being at low lifetime risk, no specific surveillance will be proposed.