MAPK3 and cancer: The expression of cancer alleles affects the regulation of downstream signaling pathways as confirmed by serum deprivation experiments (Figure S1): in fact, serum starvation elicited a dose-dependent reduction of phosphorylation of AKT(Ser473), of EGFR(Tyr1068), and ERK1/2(Thr202/Tyr204) in wild type HME cells, while isogenic clones, expressing the oncogenes, did not specifically reduce the phosphorylation of the same substrates (Figure S1).