MCL1 and neoplasm: We found that exposure to FGF2, FGF18, HBEGF, IGF1, PDGF-BB, and TGFα significantly (p < 0.0001) increased MCL1 expression in tumor cells (by at least 1.2-fold and up to 2-fold) and treatment with the MEKi reduced this response (Fig. 6A).