Moreover, after adjusted by age, gender, histology of the cancer, smoking status, and line of treatment, the methylation of SFRP5 gene was still significantly associated with a shorter PFS (P = 0.008; harzard ratio, 2.165, 95% CI, 1.2-3.8; Cox proportional hazards models of survival analysis), while the methylation of WIF1 gene was no longer associated with a shorter PFS (P = 0.224; hazard ratio, 1.804, 95% CI, 0.7-4.7; Cox proportional hazards models of survival analysis) (Table4). Here, SFRP5 is linked to cancer.