ABSTRACT
The mitogen-activated protein kinase (MAPK) pathway is an intracellular signaling pathway regulating cell cycle and other cellular functions, which is commonly aberrant in human tumors.1 This activated kinase cascade drives a serial phosphorylation of the MEK and ERK kinases that concludes in proliferation and survival. The activated MAPK pathway plays a critical role in proliferation, cell motility, and cell survival. Downstream substrates of ERK include nuclear targets such as ETS and AP-1, which are transcription factors and apoptotic regulators.2 With respect to cell proliferation, ERK1/2 is specially important in the expression of cyclin D1 to promote progression through the G1 phase of the cell cycle.3
