Suppressing the Suppressors

Last week's termination of Cell Genesys Inc.'s Phase III trial of GVAX for prostate cancer is the latest in a long line of failures for cancer vaccine developers. A variety of molecular and cellular mechanisms have contributed to the disappointing outcomes, but a key driver remains the ability of the tumor microenvironment to suppress the host antitumor response.

New research now has identified a signaling pathway that is activated in immunosuppressive myeloid cells within the microenvironment, raising the possibility that this pathway could be targeted to overcome immunosuppression and boost cancer vaccine efficacy...