Expression of 90K (Mac-2 BP) correlates with distant metastasis and predicts survival in stage I non-small cell lung cancer patients.

90K, also known as Mac-2 binding protein, is a secreted glycoprotein that binds galectins, beta1-integrins, collagens, and fibronectin, and has some relevance in cell-cell and cell-extracellular matrix adhesion. Previous studies have shown that serum levels of 90K have prognostic value in several neoplasms. In the present study, the role of the expression of 90K as an adverse prognostic indicator in 72 pathological stage I non-small cell lung cancer patients was investigated immunohistochemically. All of the patients underwent complete surgical removal of the tumor. The median length of follow-up care was 54 months. High level of 90K expression (90K staining of > or =50% of the neoplastic cells) was observed in 20 of the 72 (28%) tumors. Expression of 90K was confirmed by ELISA. The results showed that a high expression of 90K correlates with adverse prognosis. Among patients with high 90K expression, the disease-free and overall survival rates were significantly lower than the same rates of those with low expression (P = 0. 0001 and P = 0. 0003, respectively). The incidence of distant metastases in the patients with high 90K expression (60%; 12 of 20 patients) was significantly higher than that of in the patients with low expression (21%; 11 of 53 patients; P = 0.0038). The results of multivariate analysis confirmed that a high 90K expression was a significant factor to predict poor prognosis. We suggest that 90K expression could be a useful prognostic factor in patients with stage I non-small cell lung cancer, likely as an indicator of the metastatic propensity of the tumor.