Frequency Of Hereditary Non-polyposis Colorectal Cancer Research Articles

Mismatch repair protein expression in Amsterdam II criteria-positive patients in Taiwan

Hereditary non-polyposis colorectal cancer (HNPCC) is characterized genetically by germline mutations in DNA mismatch repair (MMR) genes. Immunohistochemistry (IHC) has high sensitivity and specificity for identifying MMR-deficient tumours. This study investigated the clinical presentations and frequency of HNPCC in Taiwan by combined Amsterdam II criteria (AC-II) and IHC. In 1995-2003, 7108 patients with primary colorectal cancer registered in Chang Gung Memorial Hospital's Colorectal Cancer Registry were screened using AC-II. Tumour specimens were analysed for MMR protein expression by IHC, and relevant clinicopathological details were documented. Some 83 patients fulfilled the AC-II. Clinicopathologically, 43 patients (52 per cent) had proximal tumours, ten (12 per cent) had poorly differentiated cancers, 17 (20 per cent) had mucinous adenocarcinoma and 51 (61 per cent) had stage I-II tumours. Seventeen patients developed second primary colonic and extracolonic cancers over a mean 7.2-year follow-up. Immunohistochemically, 58 patients were MMR protein deficient. They had a significantly earlier age of onset (P < 0.001), more proximal tumour location (P = 0.002), less advanced tumour stage (P = 0.008) and more second primary cancers (P = 0.017) compared with MMR-competent patients. These data show significant differences in clinical features between MMR protein-deficient and MMR competent subgroups.

Clinical and molecular analysis of hereditary non-polyposis colorectal cancer in Chinese colorectal cancer patients

To analyze the frequency of hereditary non-polyposis colorectal cancer (HNPCC) in Chinese colorectal cancer (CRC) patients, and to discuss the value of microsatellite instability (MSI) and/or immunohistochemistry (IHC) for MSH2/MLH1 protein analysis as pre-screening tests in China. The Amsterdam criteria I and II (clinical diagnosis) and/or germline hMLH1/hMSH2 mutations (genetic diagnosis) were used to classify HNPCC families. Genetic tests, including microsatellite instability, immunohistochemistry for MSH2/MLH1 proteins and hMSH2/hMLH1 genes, were performed in each proband. From July 2000 to June 2004, 1988 patients with colorectal cancer were analysed and 114 CRC patients (5.7%) from 48 families were categorized as having HNPCC, including 76 from 26 families diagnosed clinically and 38 from the other 22 families diagnosed genetically. The sensitivity and specificity of high MSI and IHC for predicting mutations were 100% and 54%, and 79% and 77%, respectively. The frequency of HNPCC is approximately 10% among all Chinese CRC cases. The MSI and IHC detections for hMSH2/hMLH1 proteins are reliable pre-screening tests for hMLH1/hMSH2 germline mutations in families suspected of having HNPCC.

Clinical characteristics and diagnosis of patients with hereditary nonpolyposis colorectal cancer.

To study the clinical characteristics of hereditary nonpolyposis colorectal cancer (HNPCC) in the Chinese population and discuss the identification and management of the patients with HNPCC. A series of 140 patients with colorectal cancers (CRC) and HNPCC associated tumors from 30 families fulfilling the Amsterdam criteria were analyzed. A total of 118 patients had CRC. Average age at diagnosis of the first CRC was 45.7 years, 56.8 % and 23.4 % of the first CRC were located proximal to the splenic flexure and in the rectum respectively. Twenty-three (19.5 %) had synchronous and metachronous CRC. Twenty-seven patients were found to have extracolonic tumors. Gastric carcinoma was the most common tumor type in our series (44.4 %). The frequency of HNPCC was 2.6 % in our series of patients. The main features are an excess of early onset with a propensity to involve the proximal colon, and high frequency of multiple foci. Management and surveillance for these patients should be different from sporadic CRC. Contrary to American and European reports, gastric cancer seems more frequent than endometrial cancer in Chinese. It is necessary to formulate a new HNPCC criterion for Chinese patients.

Microsatellite instability and hMLH1/hMSH2 expression in young endometrial carcinoma patients: associations with family history and histopathology.

Endometrial cancer is the second most common malignancy in patients with hereditary nonpolyposis colorectal cancer (HNPCC). The age at diagnosis of HNPCC-associated endometrial cancer is approximately 15 years younger than for sporadic endometrial cancer. Our current study was undertaken to determine the frequency of microsatellite instability (MSI) and absence of hMLH1 or hMSH2 protein expression in young patients with endometrial carcinoma and to correlate these findings with histopathologic and clinical features. Endometrial carcinoma from 62 women (23-52 years, median age 46) were assessed for MSI. Twenty-one of the 62 (34%) tumors demonstrated MSI. Of the 21 tumors demonstrating MSI, 12 showed an absence of hMLH1 expression, 4 showed an absence of hMSH2 expression, and 5 demonstrated normal expression of both proteins. All 41 tumors without MSI demonstrated normal hMLH1 and hMSH2 expression. Two patients with MSI tumors fulfilled the Amsterdam criteria for HNPCC, while 2 had histories suggestive of HNPCC. None of the patients with tumors without MSI had a personal or family cancer history suggestive of HNPCC. The MSI phenotype was associated (p < 0.05) with high FIGO stage and grade, cribriform growth pattern, mucinous differentiation and necrosis. Our findings suggest that the frequency of HNPCC in young endometrial cancer patients is relatively low when compared with the frequency of HNPCC in young colorectal cancer patients. Defects of the MMR proteins hMSH2 or hMLH1 account for MSI in most but not all endometrial cancers from young patients.

Frequency of hereditary nonpolyposis colorectal cancer. A prospective multicenter study in Finland.

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant cancer syndrome characterized by early onset of colorectal carcinomas (CRC). Recently, two HNPCC genes have been mapped and cloned, one in the short arm of chromosome 2 and another in the short arm of chromosome 3. There has been a major controversy about the frequency of HNPCC. The few estimates available have been based on series selected by age or series representing local area. The purpose of the present study was to design a nonselected, prospective, multicenter study, taking into account the family background and other risk factors of CRC. The proportion of HNPCC of all (N = 406) CRC cases was evaluated in a prospective multicenter study. Family history and other risk factors were investigated over a 12-month period for all new CRC patients in ten hospitals. These cases constituted 23 percent of all CRCs diagnosed in Finland during the study period. Three (0.7 percent) cases of verified and seven (1.7 percent) cases of suspected HNPCC were identified, following the evaluation of all families with features indicative of susceptibility to cancer. The proportion of identifiable risk factors of CRC was 5.8-7.5 percent (HNPCC, 0.7-2.4 percent; previous CRC, 3.4 percent; ulcerative colitis, 1.0 percent; familial adenomatous polyposis coli, 0.7 percent). CONCLUSION. This prospective multicenter study revealed that the frequency of hereditary colorectal cancer is lower than in some previous studies, when diagnosis is based on extensive pedigree analysis. This result with recent findings of common ancestral founding mutation in Finnish HNPCC families indicates that there may be geographic differences in the occurrence of HNPCC. However, this does not change the fact that identification of HNPCC--perhaps one of the most common inherited diseases identified in humans--has become a question of vital importance now when diagnosis of the syndrome and large-scale screening of gene carriers using specific tests are on the horizon.

Prevalence of hereditary nonpolyposis colorectal carcinoma (HNPCC).

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease characterized by the early occurrence of colorectal cancer--usually located in the right colon--frequent synchronous and metachronous colorectal malignancies, and association with tumors of other organs (especially endometrium, skin and stomach). In typical cases the diagnosis may be easy, but in many other instances small size of families, possible low penetrance and frequency of phenocopies may render the identification of these families extremely more complex. To provide a basis of uniformity in assessing HNPCC families, well-defined clinical guidelines have recently been proposed (the "Amsterdam Criteria"). Various studies, in different countries, indicate that the frequency of HNPCC is in the order of 3 to 5% of all colorectal tumors; at variance with these observations, much lower rates have recently been detected in Northern Ireland. The reasons of these differences are unclear. Segregation analysis repeatedly showed that the autosomal dominant inheritance was the most plausible model in order to explain cancer aggregation and verticality in HNPCC families; in accordance with this view, recessive and polygenic models were usually rejected. In addition, various anecdotal reports support the Mendelian nature of HNPCC. In conclusion, the identification of HNPCC remains a difficult task in many cases; moreover, it is likely that in analogy with adenomatosis coli 'single cases' (i.e., first mutation) might be frequent, and at present we can only suspect the disease in a single individual. It is likely, however, that the recent and exciting results of molecular biology will give in a few years of substantial contribution in the management of these patients.