[Retinoid expression (RARbeta and CRBP1) in non-small-cell lung carcinoma]

Although early-stage non-small-cell lung carcinoma (NSCLC) patients have a relative by favorable prognosis, the risk of a bad outcome remains substantial. Identification of reliable prognostic markers for disease recurrence and death has meaningful clinical application. Retinoids are involved in cell growth and differentiation and may antagonize cancer progression. Their effects are mediated through nuclear receptors called Retinoic Acid Receptor (RAR) and regulated by molecules such as Cellular Retinol-Binding Protein 1 (CRBP1) that function in retinol storage. The aim of this work was to analyze by immunohistochemistry the expression patterns of RARbeta and CRBP1, involved in retinoid-mediated signaling, in the tumoral tissue of a cohort of stage I/II NSCLC patients (n = 49) who underwent a successful surgical resection. Prognostic evaluation was performed with the multivariate Cox proportional hazard model: 44.9% of tumors were positive for RARbeta staining at cytoplasmic level, while 34.7% showed nuclear staining. CRBP1 staining was observed in 61.2% of the lung tumors. No relationship was found between the number of cells expressing the studied molecules and clinical pathological features, including sex, T and N (stage), histopathology and p53 expression. Univariate analysis showed a significant association between positive cytoplasmatic expression of RARbeta with shorter overall survival (Log-rank test 4.17, p = 0.0412). Multivariate studies indicated that RARbeta expression was not influenced by other clinical pathological parameters. In conclusion, in this cohort of stage I and II NSCLC, only the expression of RARbeta at cytoplasmatic level is a significant independent unfavorable prognostic factor.