Accordingly, scintigraphy with a moderately-selective Sig1R ligand (N-[2-(1′-Piperidinyl) Ethyl]-3-123I-Iodo-4-Methoxybenzamide) on patients with primary breast cancer revealed that the ligand was specifically retained within the tumor site, but not in healthy tissues (Caveliers et al., 2001). This evidence concerns the gene SIGMAR1 and breast cancer.