Next, to investigate the immunogenicity of these four PTHrP peptides, the PBMCs of 10 HLA-A24+ healthy donors and 10 HLA-A24+ prostate cancer patients were stimulated with each of four PTHrP peptides, and were then examined for their IFN-γ production in response to C1R-A24 cells, which were prepulsed with either a corresponding PTHrP peptide or the HIV peptide (Table 1). Here, PTHLH is linked to prostate carcinoma.