PURPOSE: to evaluate the expression of cyclooxygenase-2 (COX-2) in ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), adjacent normal stroma, and epithelium. The correlation of expression levels with nuclear grade, histological grade, presence or absence of comedonecrosis, tumor size, and patient age was also analyzed. METHODS: forty-seven surgical samples obtained from mastectomy and quadrantectomy with simultaneous DCIS and IDC, stages I and II were included. Anti-COX-2 polyclonal antibodies were used to determine enzyme expression. Samples were classified from zero to three, in accordance with number and intensity of stained cells. RESULTS: COX-2 was positively expressed in IDC, DCIS, and normal epithelium in 86.7, 84.4, and 73.3% of the cases, respectively. Concerning nuclear grade (NG), COX-2 expression was positive in 80% of cases of NG-I; in 81.5 and 78.9% of NG II, and in 88.5 and 96.1% of NG III in DCIS and IDC, respectively. COX-2 expression occurred in 78.9% of DCIS with comedonecrosis and in 89.3% without comedonecrosis. As to histological grade (HG) of IDC, COX-2 was positive in 83.3% of HG-I; 89.9% of HG-II and 80% of HG-III. Concerning tumor diameter, COX-2 was present in 86.1% of IDC cases and in 83.3% of DCIS larger than 2 cm and in 11% of IDC and DCIS tumors ≤2 cm. The age range ≥50 years presented 90% expression for IDC and 86.7% for DCIS, and the expression was 92.5% for both IDC and DCIS in patients <50 years. CONCLUSIONS: our results demonstrated high correlation between COX-2 expression in IDC, DCIS and in the normal epithelium, which is consistent with the hypothesis that COX-2 over expression is an early event in breast carcinogenesis. There was no significant correlation between COX-2 expression in IDC and DCIS and nuclear grade, histological grade, presence of comedonecrosis, age group and tumor size.
Breast neoplasms; Carcinoma, ductal, breast; Carcinoma, intraductal, noninfiltrating; Cyclooxygenase 2; Immunohistochemistry
