Biology and clinical applications of CD40 in cancer treatment

CD40 is a costimulatory molecule widely expressed by immune cells and by neoplastic cells of different histotypes. Engagement of surface CD40 mediates different effects depending on cell type and microenvironment. In particular, CD40 expression on immune cells regulates humoral and cellular immunity, while it has apoptotic and antiproliferative activity on selected neoplastic cells. Thus, CD40 targeting may indirectly affect tumor growth through the activation of immune cells and/or directly by mediating cytotoxic effects on neoplastic cells. Preliminary findings emerging from clinical trials indicate that antibodies to CD40 can induce immune modulation and clinical responses in cancer patients.