Expression of Bcl-2 is a favorable prognostic biomarker in lung squamous cell carcinoma

Lung squamous cell carcinoma (LUSC) is the second major type of lung cancer globally. The majority of patients with LUSC are clinically diagnosed at the advanced stages, thus it is urgent to identify suitable prognostic markers for LUSC. B-cell lymphoma 2 (Bcl-2) has been widely studied in non-small cell lung cancer (NSCLC). However, the prognostic role of Bcl-2 in NSCLC remains conflicting and controversial, particularly for LUSC. Although certain studies have been performed to identify the prognostic value of Bcl-2, to the best of our knowledge, no study has investigated the prognostic role of Bcl-2 in LUSC specifically. The present study aimed to comprehensively evaluate the prognostic value of Bcl-2 in LUSC. Microarray data for LUSC were downloaded from public databases, including the Gene Expression Omnibus and The Cancer Genome Atlas. Microarray data of 901 patients with LUSC from 16 data sets were retrieved. The meta-z algorithm was applied and the combined z score was identified as -2.43, suggesting Bcl-2 is a favorable prognostic biomarker. Furthermore, immunohistochemical staining of Bcl-2 expression was performed in a tissue microarray of 72 patients with LUSC and survival analysis demonstrated that patients with high expression Bcl-2 exhibited significantly more improved overall survival rates compared with those with low Bcl-2 expression. Multivariate Cox regression revealed that high expression of Bcl-2 is an independent favorable prognostic factor (hazard ratio, 0.295; confidence interval, 0.097-0.904; P<0.05). Therefore, the results of the present study demonstrated that Bcl-2 is a favorable prognostic biomarker in LUSC.