In a phase I study of a DNA vaccine encoding PAP in 22 patients with castration-sensitive prostate cancer, 41% of patients developed PAP-specific CD4+ and/or CD8+ T-cell proliferation, and 14% developed PAP-specific IFN-γ-secreting CD8+ T cells by ELISPOT assay [27]. The gene discussed is CD8A; the disease is prostate cancer.