Several state-of-the-art treatment strategies have been developed for LSCC, including molecular targeted therapy, gene therapy and immunotherapy. However, no treatment could achieve satisfactory therapeutic outcome and the survival rate of LSCC has not been improved significantly. Recent studies suggest several molecular markers of LSCC[22–24]. Further identification of prognostic markers for LSCC will be important for the prevention and therapy of LSCC.
αB-crystallin has been shown to be overexpressed in numerous kinds of tumors, including gliomas, prostate cancer, oral squamous cell carcinomas, renal cell carcinomas, and head and neck cancer. Recently, an oncogenic role of αB-crystallin has been proposed for breast cancer. The neoplastic changes and invasive phenotypes of breast cells and the anti-apopototic activities of αB-crystallin were inhibited by the phosphorylation of αB-crystallin[27, 28]. Furthermore, αB-crystallin could promote tumor angiogenesis by modulating VEGF[13, 14]. These studies demonstrate that αB-crystallin plays crucial role in tumor progression.
In the present study, the mRNA and protein levels of αB-crystallin in LSCC and tumor-adjacent normal tissues were detected by qPCR and immunohistochemistry. Both analyses showed that αB-crystallin was highly expressed in LSCC compared to tumor-adjacent normal tissues. These results agree with previous report which showed that αB-crystallin was overexpressed in hepatocellular carcinoma cells compared with non-tumour cells. Moreover, we found that the high expression of αB-crystallin in LSCC was related to alcohol consumption, tumor differentiation, pTNM stage and 5-year survival.
Univariate analysis showed that not only αB-crystallin expression, but also the pTNM stage, lymph node metastasis and tumor differentiation were correlated with life span of LSCC patients. Multivariate analysis revealed that strong expression of αB-crystallin could be considered as an independent factor for poor prognosis of LSCC patients, as well as pTNM stage and lymph node metastasis.
Interestingly, several studies suggest that αB-crystallin acts as a tumor suppressor gene in certain types of cancer[29–31]. In addition, αB-crystallin staining was reported to be reduced in head and neck squamous cell carcinoma and αB-crystallin was not proposed as a prognostic marker[32, 33]. Our present data are inconsistent with these studies. These conflicting results may be due to the differences in the pathological samples, the antibodies used, the experimental methods or evaluation system.
In conclusion, to the best of our knowledge, this is the first study to report that high αB-crystallin expression is correlated with aggressive malignant phenotype of LSCC. Our data indicate that αB-crystallin may serve as a novel prognostic marker for LSCC. Further studies are needed to confirm the prognostic and therapeutic value of αB-crystallin for LSCC.