One molecular mechanism possibly related to rapid tumor growth and the lack of response to brigatinib was the CDKN2A deletion detected in the third tumor rebiopsy (Table 1), which promotes lung cancer progression and also impairs TKI responses in the similar constellation of EGFR-mutated lung cancer (Jiang et al. 2016; Liu et al. 2020). The gene discussed is CDKN2A; the disease is lung carcinoma.