Abstract: The invention provides an oil-based pharmaceutical composition comprising as an active ingredient phostphatidylserine or a derivative thereof and a pharmaceutically acceptable oil-based carrier, which is formulated for topical or intratumoral administration. Preferably, the composition is an ointment or a cream. The composition can contain additional active agents as well, such as aminophospholipid translocase inhibitors, transnitrosylating agents, chemokines, cytokines, Toll-like receptor ligands, imidazoquinolines, dendritic cell differentiation factors, or combinations thereof. In another aspect, the invention provides a method of treating cancer within a patient in need of treatment by administering the inventive composition to the patient.