MMP9 and neoplasm: C5a induces the expression of the gelatinase B/MMP-9 stimulator IL-1β in monocytes [15,354] and the complement membrane attack complex induces gelatinase B/MMP-9 expression in cells protected against MAC-mediated lysis by CD59 [355], suggesting that activation of the complement system may promote tumour-associated gelatinase B/MMP-9 expression.