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Updated: Jul 19, 2026

Induction of Mesenchymal-Epithelial Transitions in Sarcoma Cells
Published on: April 7, 2017
Increased expression of cyclooxygenase-2 and Ki-67 are associated with malignant transformation of pleomorphic
Hideaki Katori1, Akinori Nozawa, Mamoru Tsukuda
1Department of Otolaryngology, Yokohama City Minato Red Cross Hospital, 3-12-1 Shin-yamashita, Naka-ku, Yokohama 231-8682, Japan. hhkatori@yahoo.co.jp
Objectives:
In the present study, we attempted to identify cyclooxygenase-2 (COX-2) expression and Ki-67 index in carcinoma ex-pleomorphic adenoma (Ca ex-PA) using quantitative immunohistochemical analysis and to compare the benign component of the neoplasia. We also aimed to relate the overexpression of COX-2 with the pathways of malignant transformation of Ca ex-PA as evidenced by distinct morphological features.
Materials And Methods:
Forty Ca ex-PA from patients treated at Department of Otolaryngology, Yokohama City University Medical Center, Yokohama, Japan, from 1999 to 2005, were selected. All Ca ex-PA showed only one malignant histological component: adenocarcinoma (23 cases), adenoid-cystic carcinoma (10), epithelial-myoepithelial carcinoma (7). The tissues were stained with monoclonal antibodies to COX-2 and Ki-67. The results were analyzed using quantitative immunohistochemical analysis. We also analyzed the association of the histological classification of the carcinomatous component.
Results:
In the immunohistochemical analysis of COX-2 and Ki-67 index, significant increase was observed in Ca ex-PA, especially with adenocarcinoma, compared to pleomorphic adenoma and sialadenitis. Quantitative assessment is more sensitive as a measure of cellular protein content as compared to standard optical density measurement.
Conclusions:
The data support the hypothesis that increased COX-2 expression is associated with early events in malignant transformation of pleomorphic adenoma.
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