EGFR and small cell lung carcinoma: Actually, NGS testing of plasma samples from NSCLC patients progressing following EGFR TKIs treatment allowed the identification of marked copy number changes in cfDNA even months before the confirmation of SCLC transformation, including copy number gain of MYCL1, SOX2, and SOX4. Moreover, loss or mutations of TP53 and RB1 genes were also observed [80,81].