SOX2 and Merkel cell skin cancer: Utilizing the samples from patients with MCC in the GSE39612 dataset, we generated a set of MCC signature genes by computing the average Pearson correlation coefficient between the expression of each gene with a set of known MCC marker genes: ENO2, NEFM, NEFH, NMB, HES6, SOX2, ATOH1, and CHGA.