In particular, the truncated form of SST5 (sst5TMD4), which is mainly expressed in medullary thyroid carcinoma cell lines, non-functioning pituitary adenomas (NFPAs), somatotropinomas, and pancreatic neuroendocrine tumors, is associated with a more aggressive tumor behavior and decreased response to SSAs [13,14,15,16,17,18]. Here, SSTR5 is linked to growth hormone-producing pituitary gland neoplasm.