Expression profile of the small heat-shock protein alpha-B-crystallin in operated-on non-small-cell lung cancer patients: clinical implication☆☆☆

Abstract

Alpha-B-crystallin, a small heat-shock protein, recently gained major interest because of its differential expression during tumourigenesis and metastasis in various epithelial tumours. The purpose of this study was to investigate the expression of alpha-B-crystallin and its biologic and prognostic significance in non-small-cell lung cancer (NSCLC). Immunohistochemical analysis was performed on a tissue microarray slide containing samples from 146 NSCLC patients who were operated on between 2004 and 2005. Cytoplasmic and nuclear staining was detected. Squamous cell carcinomas and adenocarcinomas had a distinctive profile of expression. The cytoplasmic staining of the tumours, however, is related to the local invasion - T-factor (p=0.044). Nuclear staining was more commonly detected in advanced stages, and was a biomarker of an aggressive tumour biology (p=0.042). Kaplan-Meier analysis showed that patients with positive nuclear staining had shorter overall survival (log-rank p=0.002). Using Cox's proportional hazards model, we performed multivariate analyses to assess the independent prognostic value of nuclear staining. The variables used included age, histology, gender and stage. Alpha-B-crystallin was an independent negative prognostic factor of survival in addition to clinical stage. Alpha-B-crystallin plays an essential role in NSCLC biology and its nuclear staining is an independent factor of poor survival. Its clinical application in molecular biologic substaging of NSCLC patients needs further validation.