HSPA9 and melanoma: Regarding the mechanism of the molecular action of HSP70 on the p44/p42 MAP kinase pathway, it has been reported that mortalin, which is a member of the HSP70 family, could regulate the activity of MEK1/2, which is an upstream kinase of the p44/p42 MAP kinase, via protein phosphatase 1α in human melanoma cells [24].