EGFR and colorectal cancer: In contrast to their high cetuximab sensitivity, Ba/F3 cells dependent on EGFR G719S and G724S mutants were only moderately sensitive to erlotinib with an IC50 value of ~ 0.3 μM (Additional file1: Figure S3A), consistent with previous reports on G719X mutants in vitro and in lung cancer clinical trials[30-33] and with the failure of a previously identified patient with EGFR G724S mutant colorectal cancer to respond to gefitinib[29].