First, the modest sample size of the WGS may not have had optimal statistical power to identify and validate some well-known lung cancer-related genes, such as TP53, EGRF, KRAS and BRAF. In our study, these genes were captured by the low-coverage sequencing with relative low frequencies of 19.0%, 28.6%, 28.6% and 9.5%, which was not significant enough to follow-up on in further association studies. This evidence concerns the gene KRAS and lung cancer.