CDKN2A and lung cancer: Other examples include identification of smokers with the highest risk of lung cancer up to 3 years prior to clinical diagnosis due to the promoter hypermethylation of a panel of seven genes: CDKN2A, PAX5β, MGMT, DAPK, GATA5, GATA4, and RASSF1A in sputum [9] or higher methylation frequency in NSCLC compared with normal tissues for 9 genes (APC, CDH13, KLK10, DLEC1, RASSF1A, EFEMP1, SFRP1, RAR-β, and P16INK4A) determined by methylation profiles by MSP (methylation-specific PCR) in tissue and plasma samples [10].