OBJECTIVE To investigate the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and vascular endothelial growth factor (VEGF) in lung carcinomas,and to clarify their roles in carcinoma progression.METHODS Expression of EMMPRIN and VEGF was examined with tissue microarrays (TMAs) of lung carcinomas (n = 181),and their suppression in adjacent normal lung samples (n = 40) were determined by immunohistochemistry.The results were compared with clinicopathological findings for the same tumors.RESULTS Both EMMPRIN and VEGF were occasionally expressed in pseudostratified columnar epithelium and frequently in lung carcinomas.Histologically,EMMPRIN and VEGF displayed higher levels in large (LCC) cell carcinomas than adenocarcinoma (AD),squamous (SQ) and small cell carcinomas (SCC) (P ＜ 0.05).EMMPRIN was more highly expressed in SQ as compared with AD (P ＜ 0.05),while the converse was true for VEGF (P ＜ 0.05).Binding was generally more intense for EMMPRIN in samples from male compared to female patients (P ＜ 0.05),whereas the latter tended to exhibit more VEGF expression (P ＜ 0.05).Positive associations of VEGF expression with the TNM stage and amounts of EMMPRIN were noted in the lung carcinomas (P ＜ 0.05).CONCLUSION EMMPRIN and VEGF possibly contribute to physiological repair of normal lung and histogenesis of lung carcinoma.Both proteins might be involved in the molecular basis for differences in the incidence of lung carcinoma between men and women.