By screening these sigma ligands for their cytotoxicity, we identified three potent sigma-2-selective ligands, WC-26, SV119 and RHM-138, that killed mouse breast cancer EMT-6 and human MDA-MB-435 melanoma tumour cells with EC50s in micromolar range after a 48-h exposure. The gene discussed is AP2S1; the disease is neoplasm.