C1QBP and neoplasm: This hypothesis is supported by our earlier findings that the proliferation of several cultured tumor cell lines could be inhibited in the presence of either mAb 60.11 that recognizes the C1q binding site on the tumor cell anchored gC1qR, or by a polyclonal antibody that recognizes the gC1qR binding site on the A-chain of C1q (28) indicating that both surface expressed gC1qR and C1q play an important role in cell signaling that favors proliferation.