Accordingly, in a recent study, among 64 patients with immunohistochemically confirmed NFPAs, PRL levels ranged from 33 to 250 ng/mL (~80% < 100 ng/mL) (42) By contrast, in BMSH, among 82 patients with NFPA, PRL levels ranged from 28 to 490 ng/mL (< 100 ng/mL in 82%); however, not all patients had been submitted to immunohistochemical evaluation (Table 3) (34). This evidence concerns the gene PRL and non-functioning pituitary adenoma.