Results of a phase I/II trial, conducted with DNA vaccine encoding human prostatic acid phosphatase (PAP) coadministered intradermally with GM-CSF, in prostate cancer patients (stage D0) are associated with an increased PSA doubling time (PSADT), 6.5 months pretreatment versus 9.3 months in the 1 year posttreatment [61] . A longer PSADT is associated with an extremely low risk of death from prostate cancer. Besides, 14% of patients developed PAP-specific IFN gamma-secreting CD8 + T-cells immediately after the treatment course, and 41% of patients developed PAPspecific CD4 + and/or CD8 + T-cell proliferation, confirming the preclinical studies [143] .