TERT and Merkel cell skin cancer: Our results demonstrate that (i) TERT expression and telomerase activity is highly prevalent in MCC; (ii) TERT promoter mutations are identified in > 10% of MCC, and most frequently occur at sun-exposed areas and MCV-negative tumors; (iii) The TERT gene amplification is widespread and positively correlated with TERT expression levels in MCC; and (iv) Higher levels of TERT mRNA expression are significantly associated with shorter survival time in MCC patients.