ERCC6 and Cowden syndrome 1: It has been reported that CSB-deficient cells derived from CS patients exhibit defects in transcription [7,8], oxidative damage repair [9], mitochondria function [10,11], cell division [12], telomere maintenance [13,14] and DNA double-stranded break repair pathway choice [15,16,17], indicative of a role of these additional cellular processes in the development of CS.