MET and gastric cancer: In human gastric cancer, MET amplification ranges between 4% and 23% (Deng et al., 2012; Kuniyasu et al., 1992; Lee et al., 2011; Nakajima et al., 1999; Peng et al., 2014); it remains to be determined whether MET amplification is a clinically important resistance factor for gastric cancer patients treated with afatinib in clinical trials.