Rush Hour Traffic: Directing T Cells to Tumor.

The authors comment on the results of a multicenter phase II study wherein patients with castration-resistant metastatic prostate cancer received the standard three doses of sipuleucel to determine changes in immune cell infiltrates in the paired tumor tissues. They describe the amount of infiltrating T cells found and the limitations of the study. They also discuss the implications of the study for the mechanism of action of sipuleucel-T.