Importantly, SHOC2 inactivation greatly potentiates apoptosis induced by MEKi in KRAS-mutant NSCLC cells and this correlates with complete cytotoxic responses in tissue culture and with marked tumour regressions in a xenograft model, at MEKi concentrations that otherwise only induce a reversible cytostatic response (Fig. 6). Here, KRAS is linked to non-small cell lung carcinoma.