EGF and hepatocellular carcinoma: Besides, without EGF treatment, cells harboring six HCC-derived EGFR mutants (K757E, N808S, R831C, V897A, P937L, and M947T) also displayed some level of pEGFR at Y869 in the range of 6–18%, and at Y1092 in the range of 5–45%, of the level in cells harboring T790M without EGF treatment, which was calibrated as 100%; furthermore, four of them (K757E, N808S, R831C, and P937L) clearly displayed pEGFR at both Y869 and Y1092, indicating some constitutive kinase activity (Fig. 2).