In many tumor types (lung cancer, breast cancer, pancreatic cancer, kidney cancer), complement proteins C1q, C1s, C3, C4, anaphylatoxins C3a and C5a and their receptors and regulatory proteins (such as factor B, factor H, factor I, CD55 and CD59) are most often overexpressed26–29. Here, C5 is linked to pancreatic neoplasm.