Fig. 3

Kaplan–Meier estimates of a disease-free interval (DFI) in months for training group of tumor tissues of early NSCLC patients in respect to SHOX2 promoter methylation status (P = 0.036), b overall survival (OS) in months for training group of tumor tissues of early NSCLC patients in respect to SHOX2 promoter methylation status in tumor tissues (P = 0.030), c disease-free interval (DFI) in months for validation group of early NSCLC patients in respect to SLFN11 promoter methylation in plasma-cfDNA (P = 0.042), d Disease-free interval (DFI) in months for validation group of early NSCLC patients in respect to APC promoter methylation in plasma-cfDNA (P = 0.037), e DFI in months for validation group of early stage NSCLC patients, in respect to the methylation of at least one gene in plasma-cfDNA or size-based CTC (P = 0.015)