Molecular characterization of lynch syndrome in Tunisia

Background: High rates of early colorectal cancers (CRC) are observed in Tunisia suggesting genetic susceptibility. Nevertheless, up to now no molecular studies have been performed in the Tunisian population. Aim: To evaluate the clinical and genetic characteristics of Tunisian families suspected of hereditary nonpolyposis colorectal cancer (HNPCC) and to identify new tumoral markers for CRC susceptibility leading to distinguish patients with sporadic CRC from those with familial CRC, like HNPCC. Methods: 31 unrelated families suspected of HNPCC were screened for germline mutations in MMR genes. We have also analyzed tumoral phenotype and the genetic characteristics of tumors from 51 patients with CRC meeting the Bethesda criteria. Results: 10 different germ line mutations, 8 of which were novel, were identified in 11 out of the 31 families (35.5%), 5 in MSH2 and 5 in MLH1. Our results showed that MUC5AC expression was more frequent in patients with family history of CRC (p=0.039). Conclusion: The analysis of MUC5AC expression might be very beneficial in the detection of Tunisian patients with high susceptibility to CRC.