Cellular localization of EMMPRIN predicts prognosis of patients with operable lung adenocarcinoma independent from MMP-2 and MMP-9.

Extracellular matrix metalloproteinase (MMP) inducer (EMMPRIN, CD147) is a multifunctional protein that has been implicated in cancer invasion and metastasis by the induction of MMPs. To address its role in primary tumors of human non-small-cell lung cancer we assessed whether EMMPRIN expression is associated with the expression of MMP-2 and MMP-9 and with patient survival. Primary tumors of 150 patients (65 adenocarcinomas, 58 squamous cell carcinomas, and 27 of other subtypes) with completely resected lung cancers were stained by immunohistochemistry. We assessed intensity, extent, and cellular localization of EMMPRIN staining and determined MMP-2 and MMP-9 expression. 145 tumors expressed EMMPRIN (strong expression in 61 tumors), which was predominantly localized at the tumor cell membranes in 102 (68%) patients. We could not determine any correlation between EMMPRIN expression and MMP-2 or MMP-9 expression. The prognostic relevance of EMMPRIN was evaluated by Kaplan-Meier and multivariate Cox regression analysis in patients with adenocarcinoma (n=57) and squamous cell carcinoma of the lung (n=56). The median follow-up period was 36.0 months (range 4-156 months). Staining scores for EMMPRIN and MMP-2 and MMP-9 derived from staining intensities and percentages of positive cells did not predict outcome of patients. In contrast, univariate survival analysis demonstrated that membranous localization of EMMPRIN was associated with shortened survival in patients with adenocarcinoma (P=0.03; log-rank test), but not in squamous cell carcinoma. For the former patients, membranous EMMPRIN expression was also an independent predictor of patient survival (P=0.04; Cox regression analysis). The findings point to a role of EMMPRIN for the progression of adenocarcinoma of the lung that is unrelated to its function as inducer of MMPs.