OBJECTIVESTo investigate the expression of CD34, vascular endothelial growth factor (VEGF) and its receptor Flk-1/KDR in precancerous lesion, atypical hyperplasia (AH) and infiltrating carcinoma of breast cancer and to explore the correlation between angiogenesis abnormality and the tumor progression.

METHODSOne hundred and sixty cases of resected tissues from breast cancer patients were enrolled in the study and were divided into 5 groups: 30 cases as normal controls, 30 cases with simple hyperplasia, 30 cases with AH, 20 cases with intraductal carcinoma in situ and 50 cases with infiltrating ductal carcinoma. The expression of CD34, VEGF and its receptor, Flk-1/KDR in those tissues were determined with immunohistochemical techniques. The micro vascular density (MVD) in those tissues was determined with the expression of CD34.

RESULTSThe expression level of CD34, VEGF and Flk-1/KDR were different among the groups, with the highest expression in the infiltrating ductal carcinoma group. With the progression of breast cancer, the major indexes showed no significant changes in the early stage of progression, but the expression of VEGF and Flk-1/KDR increased significantly from AH stage. Meanwhile, the MVD increased in the same way. There was significant difference between AH and intraductal carcinoma group in the expression of VEGF and Flk-1/KDR (P<0.05), but not in the MVD (P>0.05).

CONCLUSIONSAbnormality in angiogenesis may be an early event in the tumorigenesis of breast cancer. Abnormal expression of VEGF and Flk-1/KDR may be the initiating factor of angiogenesis in the process of breast hyperplasia-AH-breast cancer, it could be the molecular target of early diagnosis and treatment.