Overexpression of SOX2 Is Associated with Better Overall Survival in Squamous Cell Lung Cancer Patients Treated with Adjuvant Radiotherapy

Overexpression of SOX2 Is Associated with Better Overall Survival in Squamous Cell Lung Cancer Patients Treated with Adjuvant Radiotherapy

Cancer Research and Treatment : Official Journal of Korean Cancer Association, August 2015

26323639

Hong In Yoon, Kyu Hyun Park, Eun-Jung Lee, Ki Chang Keum, Chang Geol Lee, Chul Hoon Kim, Yong Bae Kim

The purpose of this study is to investigate the prognostic significance of SOX-2 gene amplification and expression in patients with American Joint Committee on Cancer stage III lung squamous cell carcinoma (SCC) who underwent surgery followed by adjuvant radiotherapy. Pathological specimens were obtained from 33 patients with stage III lung SCC treated with surgery followed by adjuvant radiotherapy between 1996 and 2008. SOX-2 gene amplification and protein expression were analyzed using fluorescent in situ hybridization and immunohistochemistry, respectively. Patients were divided into two groups according to their SOX-2 gene amplification and protein expression status. Kaplan-Meier estimates and a Cox proportional hazards model were used to identify the prognostic factors affecting patient survival. The median follow-up period for surviving patients was 58 months (range, 5-102). SOX-2 gene amplification was observed in 22 patients and protein overexpression in 26 patients. SOX-2 overexpression showed significant association with SOX-2 gene amplification (P=0.002). In multivariate analysis, SOX-2 overexpression was a significant prognostic factor for overall survival (OS) (Hazard ratios (HR) 0.1, 95% confidence interval (CI) 0.002-0.5, P=0.005) and disease-free survival (DFS) (HR 0.15, 95% CI 0.04-0.65, P=0.01). Age (HR 0.33, 95% CI 0.11-0.98, P=0.046) and total radiation dose (HR 0.13, 95% CI 0.02-0.7, P=0.02) were the independent prognostic factors for OS and DFS. Patients with SOX-2 amplification did not show a longer OS (P=0.95) and DFS (P=0.48). Our data suggested that SOX-2 overexpression could be used as a positive prognostic factor in patients with stage III lung SCC receiving adjuvant radiotherapy.