On the one hand, p42-MAPK (Erk2) is a kinase member of the Ras-Raf-Mek-Erk1/2 signaling pathway involved in cell proliferation, growth, and survival of cancer cells, and it is related to cancer progression and drug-resistance mechanisms in different cancer types, including in prostate cancer [24,48]. The gene discussed is MAPK1; the disease is prostate cancer.