Kaposi's sarcoma is a highly vascularized mesenchymal neoplasm arising with multiple lesions of the skin. Endogenous cannabinoids have been shown to inhibit proliferation of a wide spectrum of tumor cells. We studied the effects of cannabinoids on human Kaposi's sarcoma cell proliferation in vitro. To do so, we first investigated the presence of the cannabinoid receptors CB1 and CB2 mRNAs in the human Kaposi's sarcoma cell line KS-IMM by RT-PCR and, subsequently, the effects of the mixed CB1/CB2 agonist WIN-55,212 ...