RB1 and neoplasm: Interestingly Chabon et al. identified additional molecular alterations by CAncer Personalized Profiling by deep Sequencing (CAPP-Seq) ctDNA analysis in 46% of patients who were T790M-positive on tumor tissue, including cMET or HER2 increased gene copy number (GCN), and single nucleotide variations (SNVs) in EGFR, PIK3CA, or Rb1, suggesting that ctDNA analysis allows to more accurately identify the presence of multiple mechanisms of resistance emerging during TKI therapy38.