Inter-tumour heterogeneity of SSTR2 expression is frequent, especially in metastatic deposits, as in SI metastatic NENs it is common to find that at least one of the liver lesions, especially in larger lesions, shows either low or no expression at all of SSTR2 despite the rest of the tumour burden showing SSTR2 expression [23,24]. The gene discussed is SSTR2; the disease is neoplasm.