PTTG1 and neoplasm: GH: growth hormone; IGF-1: insulin-like growth factor-I; ULNR: upper limit of the normal age- and sex-matched range; GNAS: guanine nucleotide-binding protein, alpha stimulating; AIP: aryl hydrocarbon receptor interacting protein; PTTG: pituitary tumor transforming gene; RQ: relative quantification; NA: not applicable.