Prognostic significance of RIN1 gene expression in human non-small cell lung cancer

Ras interaction/interference 1 (RIN1), originally identified as a Ras effector protein, has been implicated in tumorigenesis and development of human cancers. The aim of this study was to detect RIN1 expression in human non-small cell lung cancer (NSCLC) and to analyze its association with prognosis of NSCLC patients. Quantitative real-time RT-PCR was performed to examine the expression of RIN1 mRNA in 25 cases of NSCLC and corresponding non-tumor tissue samples. Immunohistochemistry was performed to detect the expression of RIN1 in 90 NSCLC tissues. We found that the expression levels of RIN1 mRNA in NSCLC tissues were significantly higher than those in corresponding non-tumor tissues. High-level RIN1 expression was observed in 53.3% (48 of 90 cases), and correlated with poor tumor differentiation (P=0.024), TNM stage (P=0.032), and lymph node metastasis (P=0.018). Patients with high expression levels of RIN1 showed lower overall survival rate than those with low expression levels (P=0.033). Multivariate analysis showed that high RIN1 protein expression was an independent prognostic factor for NSCLC patients (P=0.021). Our study suggests that over-expression of RIN1 may play an important role in the progression of NSCLC and RIN1 expression may offer a valuable marker for predicting the outcome of patients with NSCLC.