The activation of ERK1/2 in response to CTS in cancer cells suggests that the Ras-Raf-MEK-ERK pathway plays an important role in cell survival, possibly through the regulation of ion channels and cell volume after an increase in intracellular Ca2+ and/or by inhibiting p53 protein synthesis and downstream pro-arrest or apoptosis gene expression. The gene discussed is MAPK3; the disease is cancer.