...NRAS G12D mutation but is WT for other components of the pathway, was similarly treated and examined for pERK inhibition. There was complete inhibition of pERK by 10 μmol/L U0126 ( Fig. 5A ) and 20 μmol/L PD98059 (data not shown) after both 8 and 24 h of incubation and a cytotoxic effect was seen for both compounds.