The pooled OR from 9 studies including 268 and 809 NSCLC with and without smoking history is shown in Fig. 4 (OR = 0.69, 95% CI = 0.51–0.93, p = 0.02), indicates that FHIT hypermethylation is correlated with smoking status in NSCLC patients. The gene discussed is FHIT; the disease is non-small cell lung carcinoma.