The expression levels and prognostic value of high temperature required A2 (HtrA2) in NSCLC.

High temperature required A2 (HtrA2) is a serine kinase that is released from mitochondria into the cytosol upon apoptotic stimuli, inducing apoptosis in various cancers. Thus, analysis of the expression of HtrA2 in non-small-cell lung cancer (NSCLC) tissues is needed for the understanding of this malignancy. In this study we firstly analyzed the apoptosis effect of HtrA2 in A549 cells by RNA interference and cisplatin with Western blot and flow cytometry. Then HtrA2 expression was evaluated by Western blot and immunohistochemistry in NSCLC tissues. Western blot and flow cytometry analyses indicated that deletion of HtrA2 was negatively correlated with apoptosis-induced protein in A549 cells. HtrA2 was lowly expressed in NSCLC and significantly associated with histological differentiation and clinical stage. Besides, low expression of HtrA2 was a prognostic factor for NSCLC patients' inferior survival. In conclusion, HtrA2 might promote the apoptosis of NSCLC cells, and serve as a target for NSCLC's treatment.