Comparing the cancer cell fraction (CCF) of EGFR mutations across different stages demonstrated that EGFR mutations were only present as minor subclones in AAH (mean CCF = 0.11), which became major subclones in AIS (mean CCF = 0.66), MIA (mean CCF = 0.54) and ADC (mean CCF = 0.71). This evidence concerns the gene EGFR and cancer.