To investigate the clinical relevance of DARPP-32 given its role in promoting resistance to EGFR first-generation TKIs in mouse models of human NSCLC, we assessed DARPP-32, p-EGFR, total EGFR, p-ERBB3, and total ERBB3 protein expression by immunostaining in paired EGFR TKI-naive and -resistant specimens from 30 LUAD patients (Supplementary Table 1). Here, ERBB3 is linked to non-small cell lung carcinoma.