The VEGF-Hypoxia Signature is Upregulated in Basal like Breast Tumors from Women of African Ancestry and Associated with Poor Outcomes in Breast Cancer.

Abstract

Black women experience the highest breast cancer mortality rate compared to women of other racial/ethnic groups. To gain a deeper understanding of breast cancer heterogeneity across diverse populations, we examined a VEGF-hypoxia gene expression signature in breast tumors from women of diverse ancestry. We developed a NanoString nCounter gene expression panel and applied it to breast tumors from Nigeria (n=182) and the University of Chicago (n=161). We also analyzed RNA sequencing data from Nigeria (n=84) and TCGA datasets (n=863). Patient prognosis was analyzed using multiple datasets. The VEGF-hypoxia signature was highest in the basal-like subtype compared to other subtypes, with greater expression in Black women compared to White women. In the TCGA dataset, necrotic breast tumors had higher scores for the VEGF-hypoxia signature compared to non-necrosis tumors (p<0.001), with the highest proportion in the basal-like subtype. Furthermore, necrotic breast tumors have higher scores for the proliferation signature, suggesting an interaction between the VEGF-hypoxia signature, proliferation and necrosis. T cell gene expression signatures also correlated with the VEGF-hypoxia signature when testing all tumors in the TCGA dataset. Lastly, we found a significant association of the VEGF-hypoxia profile with poor outcomes when using all patients in the METABRIC (p<0.0001) and SCAN-B datasets (p=0.002). These data provide further evidence for breast cancer heterogeneity across diverse populations and molecular subtypes. Interventions selectively targeting VEGF-hypoxia and the immune microenvironment have the potential to improve overall survival in aggressive breast cancers that disproportionately impact Black women in the African Diaspora.