PRKCB and neoplasm: Given the recent knowledge that the TME can influence tumor cell proliferation (41), as well as the known function for PKCβ in endothelium and immune cells, we also investigated macrophage infiltration and tumor vasculature in the MMTV–PyMT tumors with and without PKCβ.We saw a significant decrease in percentage of F4/80 positive area, a macrophage marker, in MMTV–PyMT; Prkcb−/− tumors (Figure 2B), indicating that loss of PKCβ within macrophages influences their recruitment to the tumor site.