EGFR and neoplasm: Fluid biopsy could avoid repeated biopsies and monitor the changes of clones in real time, which detected drug resistance mutations of EGFR TKIs early and reduce missed mutations due to tumor heterogeneity.[22] However, plasma genotyping had a false negative rate of 30 percent,[23] and ignored the resistance mediated by histological transformation.[24] Therefore, patients whose fluid biopsies indicate negative drug resistance mutations still need further tumor biopsies to be combined with, which assisted in confirming the mechanism of drug resistance.