AP2S1 and neoplasm: Sigma-2 ligands with different chemical structures have been reported to induce apoptosis in several tumour cell lines (Brent et al, 1996; Crawford and Bowen, 2002; Crawford et al, 2002, 2003; Barbieri et al, 2003; Ostenfeld et al, 2005; Cassano et al, 2009).