Moreover, UV-associated MCPyV-negative MCC has been linked with the activation of JAK-STAT, MAPK (HRAS, NF1) [34] and PI3K pathways (PIK3CA, AKT1, PIK3CG), as well as the receptor tyrosine kinase FGFR2 [29]. This evidence concerns the gene PIK3CA and Merkel cell skin cancer.