To examine the contribution of the immune and blood vessel cells to tumor cell proliferation, we utilized the cytokine ELISA array platform to analyze the secreted cytokine profile of CD45+CD31+ cells obtained from three primary ER+ breast tumor samples after 10 days in 3D organoid culture (Figures 7A, S6B, and S6C). The gene discussed is PECAM1; the disease is breast neoplasm.