Expression of RNA-binding protein IMP3 (KOC) in benign urothelium and urothelial tumors.
RNA-binding protein IMP3 is a KH-domain-containing protein and a member of the insulin-like growth factor messenger RNA-binding protein family. It is identical to K-homology protein overexpressed in cancer that was identified through screening for genes differentially expressed between benign pancreatic tissue and pancreatic cancer. Several studies have shown that IMP3 is associated with aggressive and advanced tumors in various organs. We studied the expression of IMP3 in benign urothelium and urothelial tumors by immunohistochemistry. The expression pattern of IMP3 was further compared with that of p53 and p16. Our study shows that IMP3 is generally not expressed in benign urothelium or low-grade urothelial tumors including urothelial dysplasia, papillary urothelial neoplasm of low malignant potential, and low-grade papillary urothelial carcinoma. The expression of IMP3 is significantly increased in high-grade urothelial tumors including high-grade papillary urothelial carcinoma, urothelial carcinoma in situ, and invasive urothelial carcinoma. Expression of IMP3 in urothelial tumors parallels the accumulation of nuclear p53, although there is not always a one to one correlation. In contrast, expression of p16 in the different groups of urothelial tumors is more variable. Urothelial carcinomas with invasion of muscularis propria appear to express IMP3 more frequently than lower-stage tumors. These findings suggest that IMP3 may be involved in the progression of urothelial tumors from low grade to high grade in both papillary and flat lesions. Immunohistochemical detection of the combined expression of IMP3 and p53 is useful in the diagnosis of high-grade urothelial tumors, particularly in small, superficial materials.
Department of Pathology, University of Rochester Medical Center, Box 626, Rochester, NY 14642, USA.
Lin
L
Li
Haodong
H
Xu
Betsy O
BO
Spaulding
Liang
L
Cheng
Rochelle
R
Simon
Jorge L
JL
Yao
P Anthony
PA
di Sant'Agnese
Patricia A
PA
Bourne
Jiaoti
J
Huang
D019941:Cyclin-Dependent Kinase Inhibitor p16; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009363:Neoplasm Proteins / Q000032:analysis*; D016601:RNA-Binding Proteins / Q000032:analysis*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D014571:Urologic Neoplasms / Q000737:chemistry* / Q000473:pathology; D019459:Urothelium / Q000737:chemistry* / Q000473:pathology
C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; C498780:IGF2BP3 protein, human; D009363:Neoplasm Proteins; D016601:RNA-Binding Proteins; D016159:Tumor Suppressor Protein p53