EGFR and lung cancer: Resistance to the T790M mutation in lung cancer could be overcome in vitro by irreversible EGFR small molecule inhibitors such as CL-387,785 [77] and BIBW2992 [78], Hsp90 inhibition [79], combination of multiple RTK inhibitor and mTOR inhibitor [80], combination of TS-targeting drugs (5-fluorouracil or pemetrexed) and BIBW2992 [81], and novel mutant-selective EGFR kinase inhibitors [82].