A novel fusion protein, comprising a receptor-antagonizing domain and a positive immunomodulator domain, characterized, for example, by its ability to block apoptosis and/or inhibit endocrine response, is useful in treating cancer. For example, a human prolactin antagonist-interleukin 2 (hPRLA-IL-2) fusion protein combines apoptosis induction and immuno-therapy to combat cancer in the breast or prostate.