As illustrated in Figure 1A and 1D, the percentage of methylated reference (PMR) levels of SFRP1, SFRP2, PRKCB and WIF1 in 111 NSCLC tumor tissues and 111 paired adjacent tissues were quantified by SYBR green-based quantitative methylation-specific PCR (qMSP). Here, SFRP2 is linked to non-small cell lung carcinoma.