Difficulties in recognizing families with Hereditary Non-polyposis Colorectal Carcinoma. Presentation of 4 families with proven mutation

Abstract 

Introduction

Hereditary Non-polyposis Colorectal Carcinoma is the most frequent genetic disease leading to colon and other malignancies. Recognizing the condition requires extensive family history going back several generations focusing particularly on the types of tumors occurring in the family at different age groups.

Methods

In families who met the Amsterdam and Bethesda Criteria, the removed tumor tissue was first examined by immunohistochemistry and microsatellite instability analysis. Subsequently DNA sequencing was performed to detect an underlying Mismatch Repair Gene mutation and multiple ligation dependent probe amplification was applied for recognizing large deletions in Mismatch Repair Genes.

Results

In the investigated families 3 pathogen mutations, 1 large deletion and 2 cases of polymorphism were found. There is considerable difference between the families in terms of the types of malignancies and the age in which those appeared.

Conclusion

Recognizing families with Hereditary Non-polyposis Colorectal Carcinoma presents great difficulties because of the variety of phenotypes in presentation. Special attention should be paid to small families and those who present with cancer of other than colon origin. Practicing physicians should be made aware of the fact that this disease may have atypical presentations. Follow up of families who have already been screened may be difficult for social, economical or religious reasons.

Keywords: Hereditary non-polyposis colon cancer, Bethesda criteria, Phenotypical variability, hMLH1, hMSH2