KRAS and cancer: A key difference between our study and the mouse and human cell line cancer models is that these models all involved chronic K-Ras expression, whereas in our system Ras(Q61L) was expressed for only a few hours to initiate cell extrusion, and we found that inhibition of EGFR or ablation of the EGFR gene caused no reduction in Ras(Q61L)-GTP and no reduction in phospho-ERK levels.