In 1994, Greenman and Melmed analyzed SSTR 3, SSTR4, and SSTR5 in 33 pituitary adenomas and SSTR1 and SSTR2 in 27 pituitary adenomas using RT-PCR, including 2 and 3 ACTH-producing adenomas, respectively. Here, SSTR2 is linked to pituitary gland adenoma.