Cyclooxygenase-2 expression in the hereditary mixed polyposis syndrome.

Hereditary mixed polyposis syndrome (HMPS), characterized by hyperplastic, juvenile, admixed, serrated adenomas and eventually colorectal cancer, is managed by repeated polypectomy and surgery. We determined if HMPS polyps express cyclooxygenase-2 (COX-2). Nineteen recent HMPS polyps, from five family members, were stained for COX-2. Polyps' epithelium and stroma and comparison tissues (normal colonic mucosa [9], sporadic juvenile polyps [18], colorectal cancers [3]) were quantified for COX-2 by: area of staining (0-3) x intensity (0-3). Epithelial, stromal, and total scores were evaluated in relationship to histology and dysplasia. HMPS polyps COX-2 mean epithelial (5.0+/-3.0), stromal (6.9+/-1.9), and total (11.8+/-4.6) scores were significantly higher (P < 0.01) than sporadic juvenile polyps (0.6+/-0.7, 3.1+/-2.2, and 3.6+/- 2.2 respectively), while colorectal cancer scored 9, 9, and 18. There was a positive association (P < 0.01) among histology, degree of dysplasia, and COX-2 expression. COX-2 expression in HMPS polyps and its association with dysplasia suggest that chemoprevention might be a useful adjunct therapy.