promoter hypermethylation in lung squamous cell carcinoma but not in lung adenocarcinoma.

Aberrant DNA methylation is associated with non-small cell lung cancer (NSCLC), suggesting that gene promoter methylation may be a potential biomarker for the detection or risk prediction of NSCLC. The present study aimed to evaluate the potential usage of angiotensin II receptor type 1 () methylation in two major pathologic subtypes: Lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). Quantitative methylation-specific polymerase chain reaction was used to investigate the effect of promoter methylation in the tumor and the paired adjacent non-tumor tissue samples from 42 patients with LUSC, and 69 with LUAD. The percentage of methylated reference was calculated and presented as the median (interquartile range 25th-75th percentile). The results of the current study revealed that there was significantly increased promoter methylation in the tumor tissues compared with the paired adjacent non-tumor tissue [97.4 (57.22-130.5) vs. 85 (48.25-123); P=0.024]. Furthermore, higher promoter methylation was observed in patients with LUSC compared with LUAD (odds ratio=2.483; 95% confidence interval=1.125-5.480; P=0.023). Significant differences were identified in methylation between non-tumor and the tumor tissues in LUSC [113.5 (68.33-148.73) vs. 93.04 (45.94-140); P=0.008]. In addition, the Cancer Genome Atlas data of 378 patients with LUSC and 477 with LUAD revealed an inverse correlation between gene expression and the methylation status of promoter.. These data suggest that hypermethylation is a promising biomarker to assist in LUSC detection and diagnosis.