The wide spectrum of POT1 gene mutations correlates with multiple cancer types.

Abstract

The POT1 protein forms part of the shelterin complex, which binds and protects telomeres. Germline mutations in the POT1 gene have recently been shown to be involved in tumors in different tissues such as familial colorectal, glioma and melanoma tumors, which demonstrate the importance of this gene. Recently, we uncovered a mutation in the POT1 gene (p.R117C) as causative of cardiac angiosarcomas in families with multiple tumors. Our in silico studies predicted that the POT1 p.R117C protein had lost the ability to interact with TPP1 and ssDNA. In vitro studies corroborated this prediction, and showed that this lack of function leads to abnormally long telomeres with increased fragility. In order to better understand the spectrum of mutations in the POT1 gene and its relation with tumorigenesis, we extended the study to families with multiple tumors (with and without angiosarcomas) and sporadic angiosarcomas and cardiac sarcomas. We found four new mutations that were not described previously and another patient carrying the previously described p.R117C mutation. In silico studies predicted that these new mutations were damaging in the same manner as previously described for the POT1 p.R117C mutation. These mutations were present in both, families and sporadic cases with angiosarcomas and sarcomas, although the major part was involved in families with AS and in cardiac tumors. The wide spectrum of mutations in the POT1 gene leading to different tumorigenesis processes demonstrates the general importance of this gene.