Introduction: Hereditary Nonpolyposis Colorectal Cancer (HNPCC) is a disease inherited in an autosomal dominant fashion and characterized by an early onset and the occurrence of colorectal or, less frequently, gastric, urinary and gynecological cancers.
The genetic background of the disease is verified. The screening protocol has been established based on the Amsterdam and Bethesda criterias. HNPCC is often present in patients under 50 years and is characterized by a regular appearance in the succeeding generations. The cancer is more frequently located in the proximal colon and the presence of synchronous or metachronous tumors are also common. However, the prognosis is significantly better as compared to the sporadic colorectal cancers.
Patients and Methods: We sent questionnaires to 547 patients underwent surgical intervention because of histologically proven colorectal carcinoma between 1997 and 2002, screening for the possible occurrence of HNPCC according to the Amsterdam criterias. From the 348 acceptable replies we identified 14 index persons being suspect to suffer from the disease. The diagnosis has been confirmed by proving the MMR gene mutations in the isolated DNA samples gained from peripherial blood of these patients.
Results: We found the prevalence of HNPCC is 2.3 percent in our population which is lower than the 3–8 percent found in the relevant literature references. We present the pedigree of a young male patient suffering from CRC who is carrying a pathogen mutation (not yet published) and a non pathogen allele variation of MSH2 MMR gene. The age of onset of CRC's in this family indicates the clinical importance of the association of a non-pathogen polymorphism and a pathogen mutation in one person.
Conclusion: Since HNPCC is characterized by an early age at onset colorectal carcinoma and strong familiar inheritance, we believe it is important to set up a screening program to identify these index persons by means of Amsterdam criteria, and initiate their and their families regular genetical screening in Hungary.
