Optimizing microvessel counts according to tumor zone in invasive ductal carcinoma of the breast

We calculated microvessel counts (MVCs) by analyzing CD31-stained sections in three tumor zones (central, intermediate, and peripheral) in 147 cases of invasive ductal carcinoma (IDC). The purpose of the study was to discover whether there is a difference in MVC in the different zones of tumor, which zone contains the highest MVC within the tumor, from which zone the MVCs best correlate with tumor recurrence or tumor death, and which histologic factors correlate with the MVC of the tumor. Sections were scanned to assess the highest number of microvessels in any single 200 x field (0.384 mm2). In all of our cases, the average MVCs of the central, intermediate, and peripheral zones of the IDCs were 34.4, 39.4, and 51.5 per 200x field, respectively. The MVC significantly increased from the central to the peripheral zones (P < .001). In the univariate analysis, in at least one tumor zone, the MVC was correlated with T classification, tumor necrosis, fibrotic focus (a scar-like area within IDCs), and c-erbB-2 protein expression. The only factor significantly correlated with a higher MVC in all of the three zones was fibrotic focus. Moreover, in the multivariate analysis, tumors having high MVCs in the peripheral zone were significantly associated with higher hazard ratios for tumor recurrence (P < .05). This study showed that the MVC of an IDC significantly increases from the central to the peripheral zones, and it showed that angiogenesis in the peripheral zone is associated with prognosis. Therefore, estimation of angiogenesis should be performed in the peripheral zone for reliable prediction of outcome in breast cancer patients. As a surrogate for angiogenesis, fibrotic focus seems to be a useful marker for malignant potential in breast cancer.