PRL and pituitary gland adenoma: According to patients’ symptoms and the cellular-pathological features of tumors, pituitary adenomas are categorized into several subtypes including prolactin (PRL)-secreting pituitary adenomas (PRL-PA), growth hormone (GH)-secreting pituitary adenomas (GH-PA), adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTH-PA), gonadotropin-secreting pituitary adenomas (GT-PA), and null cell pituitary adenomas (NC-PA), etc. [5].