C5AR1 and neoplasm: We found that the mRNA expression of C1QA, C1QB, C1QC, C5AR1, C3AR1, C1QR (CD93), CR1, CR2, CR3 (ITGAM), and CR4 (ITGAX) were positively associated with almost all kinds of tumor immune cells, including CD8+ T cells, CD4+ T cells, B cells, macrophages, monocytes and DCs (Table 8).