Diagnostic significance of high mobility group I(Y) protein expression in intraductal papillary mucinous tumors of the pancreas.
BACKGROUND
Overexpression of the high mobility group I(Y), [HMGI(Y)], gene/proteins has been demonstrated in many types of human malignancies, suggesting that HMGI(Y) may play a vital role in the oncogenic transformation of cells.


OBJECTIVE
To analyze HMGI(Y) expression in intraductal papillary mucinous tumor (IPMT) of the pancreas to verify whether determination of the HMGI(Y) expression level could provide any diagnostic advantages in the pathological diagnosis of IPMT.


METHODS
Thirty-three different lesions from 25 patients with IPMT, including 20 with mild dysplasia, 7 with moderate dysplasia, and 6 with carcinoma, were analyzed immunohistochemically with use of an HMGI(Y)-specific antibody.


RESULTS
Immunohistochemical analysis revealed that, although no significant immunoreactivity was found in cases of normal pancreatic duct or mild dysplasia, 28.6% (2/7) of moderate dysplasia showed multifocal immunoreactivity with moderate intensity. In contrast, in 50% (3/6) of the cases of carcinoma, intense multifocal or diffuse immunoreactivity occurred, almost equivalent to that observed in cases of duct cell carcinoma, whereas in the remaining 3 cases of carcinoma only a faint focal immunoreactivity occurred. Histologic examination revealed that these HMGI(Y)-positive carcinomas had an invasive growth pattern, whereas the HMGI(Y)-negative carcinomas were either carcinomas in situ or tumors with minimal invasion. Thus, an increased expression level of HMGI(Y) proteins was closely associated with the malignant phenotype in IPMT.


CONCLUSIONS
On the basis of these findings, we propose that HMGI(Y) proteins could play an important role(s) in a multistage process of carcinogenesis of IPMT and that the HMGI(Y) protein level could serve as a potential diagnostic marker, which may enable the identification of tumor cells with potential to be biologically malignant.
Abe
Nobutsugu
N
First Department of Surgery, Kyorin University School of Medicine, Tokyo, Japan. abenbtg@kyorin-u.ac.jp
Watanabe
Takashi
T
Izumisato
Yumi
Y
Masaki
Tadahiko
T
Mori
Toshiyuki
T
Sugiyama
Masanori
M
Chiappetta
Gennaro
G
Fusco
Alfredo
A
Fujioka
Yasunori
Y
Atomi
Yutaka
Y
D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis / Q000378:metabolism*; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis / Q000378:metabolism*; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000378:metabolism*; D025741:HMGA1a Protein / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000378:metabolism*
D025741:HMGA1a Protein