Cyclin-dependent kinase inhibitor 1B (CDKN1B), also known as p27Kip1, is a crucial cell cycle regulatory protein that plays a significant role in cell cycle control; the mutations in the CDKN1B/p27Kip1 gene are reported to be associated with pituitary adenomas [28]. This evidence concerns the gene CDKN1B and pituitary gland adenoma.