A case of EGFR mutation‐positive lung adenocarcinoma in which the T790M allele fraction was increased by repeated EGFR‐TKI treatment. Issue 1 (1st November 2019) - Kimura, Hideharu; Amino, Yoshiaki; Koba, Hayato; Tambo, Yuichi; Ohkura, Noriyuki; Hara, Johsuke; Sone, Takashi; Kasahara, Kazuo