High levels of phosphatase and tensin homolog expression predict favorable prognosis in patients with non-small cell lung cancer

X.-B. Li, Y. Yang, H.-Q. Zhang, W.-T. Yue, T.-M. Zhang, B.-H. Lu, J. Li, Z. Liu, Q.-H. Wang, Y. Gao, A.-M. Hu, H.-M. Zhang, H.-L. Shi, F.-B. Hu, B.-L. Li

Department of Oncology, Beijing Chest Hospital, Capital Medical University, No. 97 Ma Chang, Tongzhou District, Beijing, China. drbaolan@sina.com

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• Oncology

OBJECTIVE: The prognostic role of phosphatase and tensin homolog (PTEN) in non-small cell lung cancer (NSCLC) has been controversial.

PATIENTS AND METHODS: In this study, levels of PTEN expression were investigated in NSCLC patients and their prognostic value in NSCLC was assessed. PTEN expression in tumor tissues from 68 NSCLC patients was analyzed using immunohistochemistry and confocal microscopy. Survival analysis was performed using the log-rank test and Cox proportional hazards regression analysis.

RESULTS: NSCLC patients classified as expressers of high levels of PTEN (n = 46) had better prognoses than those classified as expressers of low levels (mean survival 17.1 versus 12.9 months, log-rank p = 0.038). In patients with adenocarcinoma (AC), high PTEN expression (n = 9) was associated with significantly longer survival than low PTEN expression (mean survival 23.50 versus 15.54 months, log-rank p = 0.043). High levels of PTEN expression resulted in 43% reduction in risk for all NSCLC patients (HR = 0.57, 95% CI: 0.33-0.98, p = 0.041). PTEN expression and clinical stage remained significantly associated with survival after adjustment for age, sex and tumor type (HR = 0.56, 95% CI: 0.32-0.99; p = 0.048; HR = 0.54, 95% CI: 0.36-0.97; p = 0.045). No significant difference in continuous PTEN expression levels was observed among groups with different clinical or pathological characteristics (p > 0.17). When levels of PTEN expression were binarized using the optimal cutpoint, higher levels of PTEN expression were observed in patients with T1/T2 than in those with T3/T4 (80% and 58% respectively, p = 0.049) and in patients with AC than in those with squamous-cell carcinoma (SCC) (78% and 58% respectively, p = 0.08). No significant difference in binarized PTEN expression levels was found among groups with any other clinical/pathologic characteristic (p > 0.28).

CONCLUSIONS: Our results suggest that high levels of PTEN expression may be favorable prognostic marker in NSCLC patients.

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