This small retrospective study found that 74% (N = 19) of MCC samples expressed high levels of PARP1, 64% were positive for mutations in DNA damage repair genes (indicative of MCPyV-negative MCC), and sensitivity to olaparib was seen in the Merkel cell carcinoma line with highest PARP1 expression [70]. Here, PARP1 is linked to Merkel cell skin cancer.