[Show abstract][Hide abstract] ABSTRACT: It has been reported that an endogenous matrix metalloproteinase (MMP) inhibitor, reversion-inducing cysteine-rich protein with Kazal motifs (RECK), is able to inhibit tumour angiogenesis, invasion, and metastasis through inhibition of MMP-2, MMP-9, and membrane type-1 (MT1)-MMP (MMP-14) secretion and activity. In this study, using quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR), we have analysed RECK expression levels in resected non-small-cell lung cancer (NSCLC) tissue and compared these data with the clinicopathological features of these patients to investigate the role of RECK in NSCLC. We have also analysed the expression of MMP-2, MMP-9, and MMP-14 and compared the data with those for RECK expression. Tissue samples of primary lung cancers were obtained from a total of 83 patients [46 with adenocarcinomas (ADC) and 37 with squamous cell carcinomas (SCC)] who underwent curative resection. The samples were taken from 83 tumours and 20 matched normal lung tissue samples as controls. Expressions of RECK in ADC and SCC were significantly lower than in the control. In ADC tissue, the expression of RECK was higher in stage IA than in stage IB-IIIA. There was no such a correlation in SCC. In ADC, univariate analysis for relapse-free survival using Cox regression analysis identified low RECK expression (p=0.036), low MMP-14 expression (p=0.038), and tumour T2 (p=0.034) as significant negative prognostic predictors. However, in SCC, none of the clinicopathological factors assessed, including RECK expression, had prognostic value. In conclusion, our study suggests that suppression of RECK expression is involved in the progression of ADC of the lung and that RECK expression in resected ADC of the lung is a favorable predictor of patients' prognosis.