As there was no correlation between MIN development and elevated serum prolactin levels, and phospho-STAT5 expression was decreased in mammary lesions, the increased incidence of MIN lesions was most likely due to Men1 disruption rather than to prolactinoma development.
Attenuated expression of menin and p27 (Kip1) in an aggressive case of multiple endocrine neoplasia type 1 (MEN1) associated with an atypical prolactinoma and a malignant pancreatic endocrine tumor.
Patients 1 and 2 from families with MEN1, developed prolactinomas as the sole endocrinopathy but they did not harbour the germline MEN1 mutation present in their affected relatives.
These observations suggest that menin inhibits hPRL promoter activity and cell proliferation, raising the possibility that menin might play an important role in the tumorigenesis of prolactinoma.
We analyzed a Japanese MEN1 patient and her daughter for germline mutations of the MEN1 gene.The proband (60 y.o.) had primary hyperparathyroidism (PHP) and gastrinoma, and her daughter (30 y.o.) had prolactinoma.
Prolactinomas were not evenly distributed in the genealogy; in 2 branches of the overall genealogy prolactinomas were present in 50% or more of MEN 1-affected members.
We conclude that 1) in addition to prolactinomas, nonfunctioning pituitary tumors are common in MEN 1; 2) alpha-subunit hypersecretion is frequent in MEN 1; 3) comprehensive screening may identify many clinically significant but asymptomatic pituitary lesions; and 4) prolactinomas occurring in MEN 1 may behave more aggressively than sporadic prolactinomas.