ATP6AP2 and pituitary gland adenoma: Positive immunostainings for PRR were observed in 9 of 29 (31%) nonfunctional pituitary adenomas, 25 of 33 (76%) GHomas, 7 of 14 (50%) ACTH-secreting pituitary adenomas, and 1 of 7 (14%) TSH-secreting pituitary adenomas.