PTEN and neoplasm: PTEN and CDKN2A methylation levels were low and increased in late stage III and IV (p = 0.003, p = 0.004 between stage I and III, p = 0.018 and p = 0.003 between stage I and IV), while MGMT methylation levels were low and appear to decrease with tumor stage (p = 4.5e-4 between stage I and IV) (Figure 1).