PECAM1 and neoplasm: Figure 4 shows the effects of B. microti infection on tumor angiogenesis and tumor immune microenvironment. In Figure 4A, the B.m+B16 group was seen to be significantly (p ≤ 0.0332) lower (∼34%) than the B16 group in the expression of CD31 in tumors, suggesting that B. microti infection could inhibit angiogenesis in tumors (Figure 4A). The expression of F4/80 in tumor was also detected to evaluate the number of tumor-associated macrophages. In Figure 4B, B.m+B16 and B16 groups were seen to have no significant (p = 0.3003) difference in the number of macrophages.