The D-Arg PEP targeting activator family members of transcription factor E2F— namely, E2F-1, E2F-2, and E2F-3a—showed a synergistic anti-cancer effect when used in combination with chemotherapeutic drug cisplatin against the prostate cancer, breast cancer, and lymphoma cell lines. The gene discussed is E2F1; the disease is Familial prostate cancer.