Tumor Angiogenesis in Breast Cancer: Pericytes and Maturation Does Not Correlate With Lymph Node Metastasis and Molecular Subtypes

Abstract

BackgroundAngiogenesis, traditionally assessed by microvessel density (MVD), does not give an indication of the functional status of the tumor neovasculature. The structural and functional stability of the tumor vasculature and its potential clinical relevance in breast cancer was evaluated. Materials and MethodsIn invasive breast cancer, immunostaining of endothelial cells and pericytes was performed using anti-CD34 and anti–platelet-derived growth factor receptor-β antibody, respectively. Double immunostaining for the proliferating capillary index (PCI) and microvessel pericyte coverage index (MPI) was performed with CD34/Ki-67 and CD34/smooth muscle actin. ResultsThe mean MVD of 145 vessels/mm2 was significantly greater in grade 3 tumors (P = .018) and in necrotic tumors (P = .022). The PCI ranged from 0% to 17.14% (mean, 4.37%) and was associated with a high proliferative index in tumor tissue (P = .044). The MPI ranged from 13.09% to 88.18% (mean, 41.35%), indicating the stability of the tumor vasculature. However, it was not significantly associated with the tumor size, tumor grade, lymph node metastasis, proliferative index, or molecular subtypes. ConclusionMVD remains the angiogenesis-related parameter associated with tumor grade and necrosis. The PCI was the only functional parameter of angiogenesis associated with a poor prognostic indicator. The MPI did not show any correlation with the known prognostic and predictive factors.