BRAF and cancer: During the process of expansion and metastasis of lung cancer, cancer cells develop spatial and temporal diversity of genomic instability.79 Over the last decade, a series of TRACERx (TRAcking Cancer Evolution through therapy Rx) studies have extensively discussed the evolution and development of genomic intratumor heterogeneity in NSCLC.80,81 Hanjani et al. performed whole-exome sequencing on 327 tumor regions of 100 early-stage NSCLC tumors.82 Driver mutations, such as EGFR, MET, BRAF primarily occurred, and were almost always clonal.