PLA signals for EGFR homodimers tended to be higher in NSCLC cells harboring EGFR mutations than in those WT for EGFR. We further found that EGF increased EGFR homodimerization in association with induction of EGFR autophosphorylation in NSCLC cells WT for EGFR. Recent studies also found that PLA signals corresponding to EGFR-related interactions such as those between EGFR and GRB2 or between nonphosphorylated and phosphorylated forms of EGFR were higher in NSCLC cell lines positive for EGFR mutations than in those WT for EGFR [11–12]. Here, EGF is linked to non-small cell lung carcinoma.