To evaluate the diagnostic value of SHOX2 and RASSF1A gene methylation detection combined with liquid-based cytology in bronchoalveolar lavage fluid (BALF) in the diagnosis of lung cancer.

The BALF samples of 106 patients with suspected lung cancer (84 patients with lung cancer and 22 patients with benign lung lesion) were collected. The methylation of SHOX2 and RASSF1A genes in BALF was detected by PCR. Liquid-based cytology was performed using BALF samples. Using pathological results as the gold standard, the diagnostic performance of SHOX2 and RASSF1A methylation detection as well as the liquid-based cytology of BALF was assessed.

The sensitivity and specificity of SHOX2 combined with RASSF1A methylation detection were 52.4% and 100%, respectively. In the subgroup analysis of lung cancer types, the diagnostic accuracy of methylation detection was 66.7%, 72.0%, and 35.9% in small cell lung cancer, squamous cell lung cancer, and lung adenocarcinoma, respectively. The positive rate of combined detection of SHOX2 and RASSF1A gene methylation was 60.0% in advanced lung cancer, higher than that in early lung cancer. The sensitivity and specificity of cytology detection was 44.0% and 95.5%, respectively. The sensitivity of methylation detection combined with cytology detection was 65.5%.

The methylation analysis of SHOX2 and RASSF1A genes in BALF has good sensitivity and specificity in the diagnosis of lung cancer. SHOX2 and RASSF1A methylation analysis combined with cytology can significantly improve the sensitivity of lung cancer diagnosis, and is an effective supplement for pathological diagnosis of lung cancer.