More interestingly, we observed that this CD4+ T cell population expressed cytotoxic marker genes such as Ifng, Nkg7, Lamp1, Lamp2, Klrc1, and Runx3 highly expressed in sub-cluster 2 and decreased expression of CD27 [53,54], suggestive of the cytotoxic functions of CD4+ T cells during skin tumor progression. This evidence concerns the gene CD27 and skin neoplasm.