Diagnostic and prognostic significance of receptor-binding cancer antigen expressed on SiSo cells in lung-cancer-associated pleural effusion.

Objective: This study aimed to evaluate the diagnostic and prognostic value of pleural effusion levels of soluble receptor-binding cancer antigen expressed on SiSo cells (sRCAS1) in lung cancer patients with malignant pleural effusion (MPE).

Methods: Pleural effusion samples were collected from 78 patients with MPE, and from 48 patients with benign pleural effusion (BPE). Pleural effusion sRCAS1 concentrations were measured by enzyme-linked immunosorbent assay.

Results: MPE has significantly higher sRCAS1 levels than that of BPE (P < .01). With a cutoff value of 18.7 U/mL, sRCAS1 showed a good diagnostic performance for MPE. Univariate and multivariate analysis indicated that elevated sRCAS1 levels were an independent predictor of overall survival (OS) and disease-free survival (DFS). Kaplan-Meier survival curves further confirmed that patients with high sRCAS1 have shorter DFS and OS (P = .026 and P = .032, respectively).

Conclusions: In conclusion, measurement of sRCAS1 might be a useful diagnostic and prognostic marker for MPE.