Abstract 1372: Microvessel proliferation by co-expression of endothelial nestin and Ki-67 is associated with a basal-like phenotype and aggressive features in breast cancer

Abstract

Abstract Angiogenesis, the formation of new blood vessels from pre-existing ones, is essential in tumour growth and metastasis. Microvessel density (MVD) is the most widely used method for quantification of tumour angiogenesis. We here present a novel angiogenesis marker, microvessel proliferation (MVP) based on a dual immunohistochemical stain of nestin and Ki-67. Nestin is an intermediate filament protein expressed in a variety of undifferentiated cells, including newly synthesized endothelial cells (1-3), and used in this study to stain the vasculature. Proliferating cells were recognized by their Ki-67 positivity, and immature microvessels were recognized by their nestin positivity combined with their morphology. Proliferating microvessels contains endothelial cells co-expressing nestin and Ki-67. Microvessel proliferation was estimated by vascular proliferation index (VPI), the ratio of vessels containing immature proliferating endothelial cells, and the total number of immature vessels. VPI was evaluated in 178 breast cancer tissue sections. High VPI showed significant association to several markers of aggressive breast cancer, including negative estrogen receptor (ER) status (p=0.003), high tumour cell proliferation by Ki-67 (p=0.004), high p53 expression (p=0.001), five immunohistochemical profiles for the basal-like phenotype (odds ratios (OR); range 2.8-6.3), and the triple negative phenotype (TNP)(p=0.040). Concerning the mode of detection, high VPI was three times more likely to be presented in an interval detected breast cancer compared with a screening detected (OR: 3.0, p<0.0005). Both in univariate and multivariate analysis, high VPI was significantly associated with poor survival (p=0.034 and p=0.022, respectively). In conclusion, activated angiogenesis, estimated by microvessel proliferation, is associated with several markers of aggressive breast cancer phenotype, basal-like breast cancer, interval detection, and a significant predictor of prognosis in this series of breast cancer. 1. Lendahl U, Zimmerman LB, McKay RD. CNS stem cells express a new class of intermediate filament protein. Cell. 1990 Feb 23;60(4):585-95. 2. Mokry J, Cizkova D, Filip S, Ehrmann J, Osterreicher J, Kolar Z, et al. Nestin expression by newly formed human blood vessels. Stem Cells Dev. 2004 Dec;13(6):658-64. 3. Mokry J, Ehrmann J, Karbanova J, Cizkova D, Soukup T, Suchanek J, et al. Expression of intermediate filament nestin in blood vessels of neural and non-neural tissues. Acta Medica (Hradec Kralove). 2008;51(3):173-9. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1372. doi:1538-7445.AM2012-1372