Low Expression of Bax Predicts Poor Prognosis in Resected Non-small Cell Lung Cancer Patients with Non-squamous Histology†

OBJECTIVE: The present study evaluated the prognostic significance of apoptosis-related proteins p53, Bax and galectin-3 in patients with non-small cell lung cancer (NSCLC) treated with surgical resection. METHODS: We investigated the expression of these proteins and their association with clinicopathologic characteristics including disease-free survival (DFS) and overall survival (OS) in 205 NSCLC patients who underwent surgical resection (Stage I, 97; II, 46; IIIA, 45; IIIB, 17) using immunohistochemistry. Eighty-eight patients (43%) received adjuvant treatment (chemotherapy: 8, radiotherapy: 24, both: 56). RESULTS: High expressions of Bax, p53 and galectin-3 were observed in 48 (23%), 81 (40%) and 105 (51%) patients, respectively. Low expression of Bax was significantly associated with male gender, squamous cell histology and low expression of galectin-3. Five-year DFS and OS of total patients were 37 and 46%, respectively. High expressions of p53 and galectin-3 were not associated with poor DFS or OS, and no significant correlation existed between low expression of Bax and outcome of patients. However, in patients with non-squamous histology (108 patients), low expression of Bax was a significant independent predictor of poor DFS (P = 0.017) and OS (P = 0.037). In addition, in patients with Stage II or III disease, low expression of Bax significantly correlated with poor DFS (P = 0.004). It was also the most significant independent poor prognostic factor second only to a large primary tumor size in Stage II or III patients with non-squamous histology. CONCLUSIONS: Low expression of Bax was significantly associated with poor prognosis in resected NSCLC patients with non-squamous histology.