Tumor angiogenesis in node-negative breast carcinomas ? relationship with epidermal growth factor receptor, estrogen receptor, and survival

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Abstract
Angiogenesis is essential for tumor growth and metastases. Studies in breast carcinomas suggest that microvessel quantitation as a measure of angiogenesis might be one of the most powerful prognostic tools available. Node negative breast cancer is a particular group for which better prognostic markers would be helpful. We therefore measured microvessel density in a series of well characterised node negative breast carcinomas to evaluate angiogenesis as a prognostic marker and assess its relationship to epidermal growth factor receptor (EGFR) and estrogen receptor (ER), which have previously been reported to be of value. 109 patients with a mean age of 55 years and a median follow-up of 25 months were examined. Vessels were immunohistochemically highlighted using an antibody to platelet endothelial cell adhesion molecule CD31, and microvessel density was quantified using a Chalkley point eyepiece graticule. No significant correlation was observed with patient age, tumor size, grade, ER, or EGFR expression. In a univariate analysis of survival, whereas ER expression was not a significant indicator of either relapse-free (RFS) or overall survival (OS), vascular count (VC) predicted both early RFS and OS (p=0.01 and p=0.028 respectively). Furthermore, in patients with ER positive tumors, a subgroup usually considered to have a good prognosis, there was a significant reduction in RFS and OS if tumors had high VCs (p=0.05 and p=0.002 respectively). A further statistically significant reduction in RFS (p=0.05) was observed for EGFR positive highly vascular tumors. In a Cox proportional hazard model, VC remained a significant prognostic indicator for both RFS and OS (p=0.04 and p=0.01) and conferred a 6.6 and 3.5 times respective increased risk of mortality and relapse. These findings suggest that quantitation of angiogenesis is an independent predictor of survival in node negative breast carcinomas, and due to these high hazard ratios might be more useful than other recently described prognostic markers in selecting patients who would benefit from adjuvant therapy.