MAPK1 and melanoma: As an example of this type of cancer cell drug addiction, it has been shown in melanoma cells that, upon cessation of treatment with BRAF and MEK inhibitors, ERK2-mediated induction of the activator protein 1 (AP1) transcription factors JUNB and FRA1 can trigger a switch in gene expression, including downregulation of B-cell lymphoma 2 (BCL2), which provokes apoptosis [28].