More than one million patients will manifest colorectal cancer (CRC) this year of which, conservatively, approximately 3% (~30,700 cases) will have Lynch syndrome (LS), the most common hereditary CRC predisposing syndrome. Each case belongs to a family with clinical needs that require genetic counseling, DNA testing for mismatch repair genes (most frequently MLH1 or MSH2) and screening for CRC. Colonoscopy is mandated, given CRC's proximal occurrence (70-80% proximal to the splenic flexure). Due to its early age of onset (average 45 years of age), colonoscopy needs to start by age 25, and because of its accelerated carcinogenesis, it should be repeated every 1 to 2 years through age 40 and then annually thereafter. Should CRC occur, subtotal colectomy may be necessary, given the marked frequency of synchronous and metachronous CRC. Because 40-60% of female patients will manifest endometrial cancer, tailored management is essential. Additional extracolonic cancers include ovary, stomach, small bowel, pancreas, hepatobiliary tract, upper uroepithelial tract, brain (Turcot variant) and sebaceous adenomas/ carcinomas (Muir-Torre variant). LS explains only 10-25% of familial CRC. Keywords colorectal cancer; endometrial cancer; hereditary cancer; hereditary nonpolyposis colorectal cancer; immunohistochemistry; Lynch syndrome; microsatellite instability; mismatch repair; mismatch repair genesThe estimated annual worldwide incidence of colorectal cancer (CRC) is 1,023,152 (1). Lynch syndrome (LS), previously called hereditary non-polyposis colorectal cancer or HNPCC, accounts, conservatively, for approximately 3% (2) of this incidence (~30,700 cases), compared with familial adenomatous polyposis (FAP) syndrome which is about one-tenth as common, occurring in only about 1 in 10,000 of the population (3,4). Hampel et al. studied 500 tumors from unselected CRC affected individuals. Among these 500 CRC patients, 18 (3.6%) had LS. When these results were added to data on 1066 previously studied patients, the entire study cohort (N = 1566) showed 44 patients (2.8; 95% confidence interval (CI), 2.1-3.8) manifesting LS. These authors concluded that approximately 1 in every 35 patients who NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript manifested CRC had LS (2). Given the mentioned worldwide incidence figures of CRC, and extrapolating from the findings of Hampel et al. that 2.8% of the CRC cases they investigated were confirmed to be LS, we arrive at a figure of approximately 28,600 cases of LS to be newly diagnosed this year, worldwide. We have only crude estimates of familial CRC, as defined by the presence of two or more first-degree relatives with CRC, but it is thought by some to involve approximately 20% of all cases of CRC (5,6). These statistics are important given that each hereditary case comes from a family that could benefit from genetic counseling, DNA testing, surveillance, and targeted management (7-9). Yet, when a patient's family risk is overlooked, so too are opportunities fo...

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SummaryThe heritability of B cell chronic lymphocytic leukemia (CLL) is relatively high; however, no predisposing mutation has been convincingly identified. We show that loss or reduced expression of death-associated protein kinase 1 (DAPK1) underlies cases of heritable predisposition to CLL and the majority of sporadic CLL. Epigenetic silencing of DAPK1 by promoter methylation occurs in almost all sporadic CLL cases. Furthermore, we defined a disease haplotype, which segregates with the CLL phenotype in a large family. DAPK1 expression of the CLL allele is downregulated by 75% in germline cells due to increased HOXB7 binding. In the blood cells from affected family members, promoter methylation results in additional loss of DAPK1 expression. Thus, reduced expression of DAPK1 can result from germline predisposition, as well as epigenetic or somatic events causing or contributing to the CLL phenotype.

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The identification of germline mutations in families with HNPCC is hampered by genetic heterogeneity and clinical variability. In previous studies, MSH2 and MLH1 mutations were found in approximately two-thirds of the Amsterdam-criteria-positive families and in much lower percentages of the Amsterdam-criteria-negative families. Therefore, a considerable proportion of HNPCC seems not to be accounted for by the major mismatch repair (MMR) genes. Does the latter result from a lack of sensitivity of mutation detection techniques, or do additional genes underlie the remaining cases? In this study we address these questions by thoroughly investigating a cohort of clinically selected North American families with HNPCC. We analyzed 59 clinically well-defined U.S. families with HNPCC for MSH2, MLH1, and MSH6 mutations. To maximize mutation detection, different techniques were employed, including denaturing gradient gel electrophoresis, Southern analysis, microsatellite instability, immunohistochemistry, and monoallelic expression analysis. In 45 (92%) of the 49 Amsterdam-criteria-positive families and in 7 (70%) of the 10 Amsterdam-criteria-negative families, a mutation was detected in one of the three analyzed MMR genes. Forty-nine mutations were in MSH2 or MLH1, and only three were in MSH6. A considerable proportion (27%) of the mutations were genomic rearrangements (12 in MSH2 and 2 in MLH1). Notably, a deletion encompassing exons 1-6 of MSH2 was detected in seven apparently unrelated families (12% of the total cohort) and was subsequently proven to be a founder. Screening of a second U.S. cohort with HNPCC from Ohio allowed the identification of two additional kindreds with the identical founder deletion. In the present study, we show that optimal mutation detection in HNPCC is achieved by combining accurate and expert clinical selection with an extensive mutation detection strategy. Notably, we identified a common North American deletion in MSH2, accounting for approximately 10% of our cohort. Genealogical, molecular, and haplotype studies showed that this deletion represents a North American founder mutation that could be traced back to the 19th century.

BACKGROUND Hereditary pancreatic carcinoma shows extant phenotypic and genotypic heterogeneity as evidenced by its integral association with a variety of hereditary cancer syndromes inclusive of the familial atypical multiple mole melanoma (FAMMM) syndrome in concert with CDKN2A (p16) germline mutations. METHODS Creighton University's familial pancreatic carcinoma resource comprises 159 families of which 19 (12%) show the FAMMM cutaneous phenotypes. The authors describe eight families with the FAMMM–pancreatic carcinoma (FAMMM‐PC) association in concert with a CDKN2A germline mutation. Each family was thoroughly educated about all facets of the study, including the molecular genetics, reduced penetrance of CDKN2A mutations, and their variable expressivity. Genetic counseling was provided to each patient. RESULTS Diversity in cancer presentation within and among the families was noteworthy, wherein melanoma predominated in certain of the families whereas pancreatic carcinoma predominated in others. Early‐onset pancreatic carcinoma (at ages 35, 45, 46, and 49 years) appeared in some of the families whereas markedly later‐onset pancreatic carcinoma occurred in others. There were four incidences of melanoma and pancreatic carcinoma as double primaries in the same individuals. One patient with melanoma and pancreatic carcinoma had a third primary of breast carcinoma. Another patient had sarcoma, esophageal carcinoma, and two melanoma primaries, whereas his daughter had sarcoma and was a carrier of a CDKN2A mutation. CONCLUSIONS The authors suggest that these tumors may collectively, in concert with CDKN2A mutations, constitute a “new” putative hereditary carcinoma syndrome referred to as FAMMM‐PC. More clinical and molecular genetic research on additional families with pancreatic carcinoma in concert with the FAMMM will be required. Cancer 2002;94:84–96. © 2002 American Cancer Society.

Hereditary forms of colorectal cancer, as is the case with virtually all forms of hereditary cancer, show extensive phenotypic and genotypic heterogeneity, a phenomenon discussed throughout this special issue of Familial Cancer. Clearly, the family physician, oncology specialist, genetic counselor, and cancer geneticist must know fully the complexity of hereditary cancer syndromes, their differential diagnosis, in order to establish a diagnosis, direct highly-targeted surveillance and management, and then be able to communicate effectively with the molecular geneticist so that an at-risk patient's DNA can be tested in accord with the syndrome of concern. Thus, a family with features of the Lynch syndrome will merit microsatellite instability testing, consideration for immunohistochemistry evaluation, and mismatch repair gene testing, while, in contrast, a patient with FAP will require APC testing. However, other germline mutations, yet to be identified, may be important should testing for these mutations prove to be absent and, therein, unrewarding to the patient. Nevertheless, our position is that if the patient's family history is consistent with one of these syndromes, but a mutation is not found in the family, we still recommend the same surveillance and management strategies for patients from families with an established cancer-causing germline mutation. Our purpose in this paper is to provide a concise coverage of the major hereditary colorectal cancer syndromes, to discuss genetic counseling, molecular genetic evaluation, highly targeted surveillance and management, so that cancer control can be maximized for these high hereditary cancer risk patients.

Hereditary ovarian cancer accounts for at least 5% of the estimated 22,000 new cases of this disease during 2009. During this same time, over 15,000 will die from malignancy ascribed to ovarian origin. The bulk of these hereditary cases fits the hereditary breast-ovarian cancer syndrome, while virtually all of the remainder will be consonant with the Lynch syndrome, disorders which are autosomal dominantly inherited. Advances in molecular genetics have led to the identification of BRCA1 and BRCA2 gene mutations which predispose to the hereditary breast-ovarian cancer syndrome, and mutations in mismatch repair genes, the most common of which are MSH2 and MLH1, which predispose to Lynch syndrome. These discoveries enable relatively certain diagnosis, limited only by their variable penetrance, so that identification of mutation carriers through a comprehensive cancer family history might be possible. This paper reviews the subject of hereditary ovarian cancer, with particular attention to its molecular genetic basis, its pathology, and its phenotypic/genotypic heterogeneity.