title: 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.
abstract: Tumors in multiple endocrine neoplasia type 1 (MEN1) are generally benign. Since information on the pathogenesis of MEN1 in malignant cases is limited, we conducted genetic analysis and compared the expression of menin, p27(Kip1)(p27)/CDKN1B and p18(Ink4C)(p18)/CDKN2C with levels in benign cases. We describe the case of a 56 year-old male with an atypical prolactinoma and malignant pancreatic neuroenocrine tumor. At age 50, he had undergone transsphenoidal surgery to remove a prolactinoma. However, the tumor relapsed twice. Histological analysis of the recurrent prolactinoma revealed the presence of prolactin, a high MIB-1 index (32.1 %), p53-positive cells (0.2%), and an unusual association with FSH-positive cells. A few years later, he was also found to have a non-functioning pancreatic tumor with probable metastasis to the extradullar region. The metastatic region tested positive for chromogranin and CD56, and negative for prolactin, with 1.2 % of cells p53-positive. Although genetic analyses of the MEN1, p27, and p18 genes demonstrated no mutation, numbers of menin, p27 and p18 immuno-positive cells were significantly down-regulated in the recurrent prolactinoma, but that of p18 was intact in the metastatic region. Furthermore, MEN1 and p27 mRNA levels of the recurrent prolactinoma were down-regulated, particularly the MEN1 mRNA level, compared to levels in 10 cases of benign prolactinoma, while the p18 mRNA level was similar to that of normal pituitary. The tumor in this case may be a subtype of MEN1 showing more aggressive and malignant features probably induced by low levels of menin and p27.
authors: Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan.
authors: Emi
authors: E
authors: Ishida
authors: Masanobu
authors: M
authors: Yamada
authors: Kazuhiko
authors: K
authors: Horiguchi
authors: Ryo
authors: R
authors: Taguchi
authors: Atsushi
authors: A
authors: Ozawa
authors: Nobuyuki
authors: N
authors: Shibusawa
authors: Koshi
authors: K
authors: Hashimoto
authors: Tetsuro
authors: T
authors: Satoh
authors: Sachiko
authors: S
authors: Yoshida
authors: Yoshiki
authors: Y
authors: Tanaka
authors: Machiko
authors: M
authors: Yokota
authors: Masahiko
authors: M
authors: Tosaka
authors: Junko
authors: J
authors: Hirato
authors: Shozo
authors: S
authors: Yamada
authors: Yuhei
authors: Y
authors: Yoshimoto
authors: Masatomo
authors: M
authors: Mori
mesh_terms: D050763:Cyclin-Dependent Kinase Inhibitor p18 / Q000235:genetics; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D018761:Multiple Endocrine Neoplasia Type 1 / Q000378:metabolism* / Q000473:pathology; D009364:Neoplasm Recurrence, Local; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010911:Pituitary Neoplasms / Q000556:secondary; D015175:Prolactinoma / Q000378:metabolism* / Q000601:surgery; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*
chemical_list: D050763:Cyclin-Dependent Kinase Inhibitor p18; C105373:MEN1 protein, human; D011518:Proto-Oncogene Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27