Different patterns of p16INK4A and p53 protein expressions in intraductal papillary-mucinous neoplasms and pancreatic intraepithelial neoplasia.
OBJECTIVE
To examine aberrations and differences of cell cycle regulatory proteins between intraductal papillary-mucinous neoplasms (IPMNs) and pancreatic intraepithelial neoplasias (PanINs).


METHODS
In total, 47 IPMN lesions and 42 PanIN lesions were obtained from 26 patients with IPMN and 16 patients who underwent pancreatic surgery for invasive pancreatic ductal cancer or other diseases. They were subjected to conventional hematoxylin-eosin staining and immunostaining for p16INK4A and p53. The percentages of immunohistochemical positivity or negativity were compared between IPMN and PanIN, in accordance with the same histological grade of atypia. The Ki-67 labeling index was also counted in each lesion.


RESULTS
Either the loss of p16INK4A expression or the overexpression of p53 was much more frequently observed among PanIN-3 than among carcinoma in situ in IPMN (P = 0.046 and 0.008, respectively). The Ki-67 labeling index was correlated with the histological grades of both PanINs and IPMNs (P = 0.0001 and P = 0.0001, respectively).


CONCLUSIONS
There are different immunohistochemical expression patterns of p16INK4A and p53 between IPMNs and PanINs. These may substantiate their different genetic progressions to invasive carcinoma.
Abe
Keiko
K
Department of Pathology I, Juntendo University School of Medicine, Tokyo, Japan. kumek@med.jutendo.ac.jp
Suda
Koichi
K
Arakawa
Atsushi
A
Yamasaki
Shigetaka
S
Sonoue
Hiroshi
H
Mitani
Keiko
K
Nobukawa
Bunsei
B
D002288:Adenocarcinoma, Mucinous / Q000378:metabolism / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D002278:Carcinoma in Situ / Q000378:metabolism* / Q000473:pathology; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000473:pathology; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D019941:Cyclin-Dependent Kinase Inhibitor p16; D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53