Serum Levels of the Cancer-Testis Antigen POTEE and Its Clinical Significance in Non-Small-Cell Lung Cancer

BACKGROUND: POTEE (POTE ankyrin domain family, member E) is a newly identified cancer-testis antigen that has been found to be expressed in a wide variety of human cancers including cancers of the colon, prostate, lung, breast, ovary, and pancreas. AIM: To measure the serum levels of POTEE in patients with non-small-cell lung cancer (NSCLC) and to explore the clinical significance of POTEE in NSCLC. PATIENTS AND METHODS: 104 NSCLC patients, 66 benign lung disease patients and 80 healthy volunteers were enrolled in this study from May 2013 to February 2014. Serum POTEE levels were measured using enzyme-linked immunosorbent assay (ELISA). Numerical variables were recorded as means ± standard deviation (SD) and analyzed by independent t tests. Categorical variables were calculated as rates and were analyzed using a χ(2) test or Fisher’s exact test. Survival curves were estimated and compared using the Kaplan-Meier method and log-rank tests. RESULTS: Serum POTEE levels were significantly higher in NSCLC patients than in benign lung disease patients and healthy controls (mean ± SD [pg/ml], 324.38± 13.84 vs. 156.93 ± 17.38 and 139.09 ± 15.80, P<0.001) and were significantly correlated with TNM stage. Survival analysis revealed that patients with low serum POTEE had longer progression-free survival (PFS) than those with high serum POTEE (P=0.021). Cox multivariate analysis indicated that POTEE was an independent prognostic factor of progression-free survival (P =0.009, hazard ratio, 2.440). CONCLUSIONS: Serum POTEE level in NSCLC patients is associated with TNM stage and is a potential prognostic factor.