Abstract: Objective: To investigate the expression of cyclooxygenase-2(COX-2) and p53 in breast carcinoma,and to evaluate its relation to microvascular density and lymph node metastasis.Methods: S-P immunohistochemistry and in situ hybridization assay were utilized to measure the protein and mRNA expression of COX-2 in 60 breast carcinoma and 20 adjacent normal tissues.The Ⅷ-RAg,p53 expression were measure by S-P immunohistochemical method,and the density of microvessel in the breast carcinoma was assayed.Results: The microvascular density(MVD) in COX-2(+) or p53(+) group was significantly higher than that in COX-2(-) or p53(-) group(P<0.01).The MVD reached the maximum in the patients whose COX-2 and p53 were both positive(P<0.01).The positive rates of p53 and COX-2 in cases with lymph node metastasis were both significantly higher than that in the cases without lymph node metastasis,respectively(P<0.05 and P<0.05).Conclusions: COX-2 and p53 are related to tumor angiogenesis and lymph node metastasis in breast carcinoma.COX-2 and p53 show a positive correlation in breast carcinoma angiogenesis.