Figure 3.

Potential therapeutic intervention points. Complement proteins can be expressed and secreted by almost all cells in the tumor microenvironment, and in the lymph nodes and are present in serum. This cartoon outlines potential targets either intracellularly or extracellularly that could be either inhibited or activated in the case of the immune cells. It is possible that in the future complement inhibiting therapeutics should be able to act extracellularly to promote immune cell antitumor immunity. Reversely intracellular complement in immune cells can be promoted as it is expected to have antitumorigenic effect and promote inflammation. Discreet complement targets present in the tumor cells but not in the immune cells and vice versa would have to be discovered to obtain full clinical efficacy of complement targeting therapy.