CDKN2A and non-small cell lung carcinoma: Of six studies only including AC patients, the subgroup analysis showed no significant difference in the association between cigarette smoking and p16INK4α methylation when comparing AC patients (OR = 2.38, 95%CI = 1.75–3.23) (Figure 3) and all NSCLC patients (OR = 2.25, 95% CI = 1.81–2.80).