CHFR and non-small cell lung carcinoma: Two studies investigated the relationship between CHFR promoter methylation in NSCLC and the status of smoking, pooled data indicated that CHFR promoter was more frequently methylated in smoking NSCLC patients than in non-smoking patients, OR was 3.67 with 95% CI 1.52–8.88, test for overall effect, Z = 2.