Little is known about the molecular biological features of large flat tumors or laterally spreading tumors (LSTs) of the colon and rectum. Methods: The cyclooxygenase (COX)–2 protein expression level of LSTs was assessed immunohistochemically and compared with that of exophytic colorectal tumors. COX-2 expression in the dysplastic epithelial cells and the interstitial cells was evaluated independently. Results: Sixty-five LSTs and 65 exophytic tumors were randomly selected from the archives, and 61 and 59, respectively, were successfully analyzed. LSTs showed significantly more intense COX-2 protein expression in the dysplastic epithelial cells than the exophytic tumors (P > 0.0001). COX-2-positive interstitial cells were also observed more frequently in LSTs than in the exophytic tumors (P = 0.015). Conclusions: Overexpression of COX-2 protein may play a crucial role in the tumorigenesis of colorectal LSTs. Chemoprevention, using nonsteroidal anti-inflammatory drugs (NSAIDs) or selective COX-2 inhibitors may be effective for treating this unique neoplasm, which sometimes defies endoscopic treatment.
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Received: April 5, 2002 / Accepted: September 13, 2002
Reprint requests to: K. Yamashita, Present address: The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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Yamashita, K., Arimura, Y., Shimizu, H. et al. Increased cyclooxygenase-2 expression in large flat colorectal tumors (laterally spreading tumors). J Gastroenterol 38, 69–73 (2003). https://doi.org/10.1007/s005350300008