The present invention relates to a novel class of anti-cancer compounds which selectively target androgen receptor (AR)-expressing cancer cells, such as prostate cancer cells and breast cancer cells. These agents comprise an androgen receptor (AR) binding moiety, which selectively targets the compounds to (AR)-expressing cancer cells, and a cytotoxic ablating moiety, such as a nitrogen mustard moiety. The inherent high density expression of the androgen receptor in certain cancers, such as prostate cancer and breast cancer, is thus used as a tool to selectively increase the intracellular concentration of cytotoxic compounds, such as alkylating agents, e.g. DNA alkylating agents, by selectively targeting the agents to the AR-expressing cancer cells. These agents, either alone or in a composition, are thus useful for treating, delaying the progression of, treating the recurrence of, suppressing, inhibiting or reducing the incidence of cancers characterized by the presence of AR-expressing cells, such as prostate cancer. Accordingly, the present invention provides a) methods of selectively killing an (AR)-expressing cancer cell; b) methods of inducing apoptosis in an (AR)-expressing cancer cell; c) methods of treating a cancer characterized by the presence of AR-expressing cells in a subject; d) methods of delaying the progression of a cancer characterized by the presence of AR-expressing cells in a subject; e) methods of treating the recurrence of a cancer characterized by the presence of AR-expressing cells in a subject; f) methods of suppressing, inhibiting or reducing the incidence of a cancer characterized by the presence of AR-expressing cells in a subject; and g) methods of treating metastasis of a cancer characterized by the presence of AR-expressing cells in a subject; by administering to the subject or by contacting the cancer cells with a compound comprising an androgen receptor ligand moiety and an alkylating moiety, such as the novel compounds described herein.