SPRR2A and cancer: While preclinical investigations demonstrated robust immunostimulatory effects of human recombinant IL-12 (rhIL-12) in hematologic and solid malignancies (8–12), early clinical trials in cancer patients revealed that systemic delivery of rhIL-12 as a single agent resulted in severe toxicity and dampened response rates correlating to dose-dependent toxic levels of IFNγ and the immunosuppressive cytokine IL-10, respectively (13–16).