Our gene prevalences for p16, MGMT, DAPK, and RASSF1A methylation in serum are very similar to that observed by Fujiwara et al (2005) in their study of serum from all stages of NSCLC and in our previous study of lung cancer survivors that examined free DNA recovered from plasma (Belinsky et al, 2005). Here, MGMT is linked to non-small cell lung carcinoma.