Aim:

Colorectal cancer (CRC) is the third most common cancer in the world. About 5-6% of all CRCs have a hereditary inheritance related with germline mutations. Mutation screening is carried out with gene panels for CRCs to manage family against to CRCs more effectively. In this study, mutation screening was performed by sequencing of APC in patients with hereditary polyposis coli and of MLH1/MSH2 in patients with hereditary non-polyposis coli and the detected mutation distributions and their properties were investigated.

Methods:

One hundred-fifty two patients with hereditary polyposis coli and 123 patients with hereditary non-polyposis coli were included to the study from Turkey and APC, MLH1 and MSH2 analysis were performed.

Results:

Thirty nine (25%) patients with hereditary polyposis coli and 24 (18.8%) patients with hereditary non-polyposis coli had mutation in APC and MLH/MSH2, respectively. Among the evaluated as pathogenic/likely pathogenic variants, 5 of them in APC, 2 of them in MLH1 and 2 of them in MSH2 have not been previously reported in the literature.

Conclusion:

This study is the most comprehensive study demonstrated that molecular genetic etiology of familial CRC in Turkey. With the explanation of familial CRC etiology, it will enable comprehensive genetic counseling and follow-up of patients/asymptomatic individuals in accordance with familial cancer management guidelines.

Keywords: Hereditary colorectal cancer, APC, MLH, MSH2, mutation