MAPK1 and cancer: Nonetheless, the sensitivity of Ras-transformed cells to growth inhibition by the MEK inhibitor PD0325901 and its partial reversal by mimicking STAT3 S727 phosphorylation, demonstrates the importance of STAT3 as one critical MEK-ERK target during transformation and suggests that inhibition of mitochondrial STAT3 activity could be a promising therapeutic approach to Ras-dependent cancers.