Prognostic value of aberrant hypermethylation in pleural effusion of lung adenocarcinoma

Lung adenocarcinoma is one of the most frequent causes of malignant pleural effusions (MPE). The presence of MPE bears a poor prognosis. Although epigenetic changes are commonly related to human neoplasia, scarce date is available on patients with MPE. We aimed to estimate the prognostic value of DNA methylation of tumor suppressor genes from pleural fluid. Thirty patients with MPE due to lung adenocarcinoma were prospectively included. Methylation-specific (MS) PCR was used to study the methylation status of the promoter region of tumor suppressor genes p16/INK4a, MGMT, BRCA1 and RARβ in pleural fluid. Clinical data and survival were collected. Survival analysis was performed using Kaplan-Meier plots and Cox regression. Hypermethylation in at least one gene was detected in 25 patients (83.3%). On multivariate analysis factors significantly associated with shorter survival were the lack of hypermethylation in any of the studied genes (hazard ratio = 9.3; p = 0.001), Charlson index ≥ 3 (hazard ratio = 9.6, p = 0.002) and no oncological treatment (hazard ratio = 11.1; p < 0.001). Analysis of aberrant promoter hypermethylation of tumor suppressor genes may be useful in predicting prognosis, but further studies are needed to validate our findings.