MAPK1 and melanoma: ERK mutations in melanoma are quite infrequent—while the MAPK1 gene mutations are observed in less than 1% of melanomas (mostly desmoplastic melanomas), MAPK2 mutations were never scored in this tumor [84]; at odds with melanoma, the gain-of-function MAPK2E322K mutation is highly represented in a variety of solid tumors, including squamous cell carcinomas of the cervix and of the head and neck [128,129].