SSTR1 and neoplasm: In the immune system, SST1 protein is expressed in lymphocytes and macrophages (Taniyama et al., 2005), consistent with the positive SST1 immunoreactivity observed in cells resembling macrophages (cluster of differentiation 68 (CD68) positive) in spleen, lymph nodes, tonsils, thymus, lung, and gut mucosa, as well as in the stroma of diverse neoplasms (Lupp et al., 2013).