title: Overexpression of carbonic anhydrase-related protein VIII in human colorectal cancer.
abstract: Carbonic anhydrase-related protein (CA-RP) VIII, which is a member of the CA gene family, has been shown to have no catalytic CA activity and its biological function is still unknown. Recently, overexpression of CAs IX and XII has been reported in certain types of malignancy. To investigate a potential role for CA-RP VIII in human colorectal epithelial carcinogenesis, colorectal tissue specimens from surgically resected adenocarcinomas (n = 60) and endoscopically polypectomized adenomas (n = 13) were analysed by immunohistochemistry using monoclonal antibodies to CA-RP VIII and Ki-67 antigen. Less than 5% of epithelial cells in normal colonic mucosae (n = 73) were CA-RP VIII-positive and these were localized to the deep part of the cryptal epithelium. Increased expression of CA-RP VIII was observed in 78% of colorectal carcinomas. An intense signal was frequently observed at the tumour invasion front and its distribution was completely different from that of Ki-67 antigen. Colorectal adenomas also showed significant immunopositivity for CA-RP VIII, but its expression level was much lower than in adenocarcinomas. These findings suggest that CA-RP VIII plays a role in the process of invasion in colorectal cancer.
authors.affiliation: First Department of Internal Medicine, Kochi Medical School, Kochi 783-8505, Japan.
authors.forename: Eiki
authors.initials: E
authors.lastname: Miyaji
authors.forename: Isao
authors.initials: I
authors.lastname: Nishimori
authors.forename: Keisuke
authors.initials: K
authors.lastname: Taniuchi
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ohtsuki
authors.forename: Saburo
authors.initials: S
authors.lastname: Onishi
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D000236:Adenoma / Q000378:metabolism; D014408:Biomarkers, Tumor; D002256:Carbonic Anhydrases / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D003106:Colon / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000378:metabolism*; D018450:Disease Progression; D006801:Humans; D007124:Immunoenzyme Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D015854:Up-Regulation; D047908:Intracellular Signaling Peptides and Proteins
chemical_list: D014408:Biomarkers, Tumor; D002256:Carbonic Anhydrases; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C512821:Car8 protein, mouse; C512818:CA8 protein, human; D047908:Intracellular Signaling Peptides and Proteins