After analysis of combining estimates of the OR from 5 studies of 445 of NSCLC (Figure 4), the rate of hypermethylation of RARβ was detected significantly higher in smoker (n = 232) than non-smoker (n = 213) (OR = 2.46, 95% CI = 1.54-3.93, p = 0.0002). This evidence concerns the gene RARB and non-small cell lung carcinoma.