MAP2K1 and neoplasm: Owing to the high and sustained expression level of MEK1/2 mRNA, and the fact that activation of the MEK–ERK pathway cannot only hamper but also promote the sensitivity of tumour cells to CDDP (Persons et al, 1999; Wang et al, 2000), in the follow-up this study was focused on the role of MEK in the course of drug-induced apoptosis.