Cox-2 Expression in Malignant Breast Tumors

Purpose: Cox-2 expression in breast carcinoma has been reported to be related to angiogenesis, lymph node metastasis and Her-2 expression. The aim of this study is to evaluate the clinicopathologic significance of Cox-2 expression in the invasive ductal carcinomas (IDC) and intraductal carcinomas (DCIS) of the breast. Methods: The materials were 353 IDC cases and 82 DCIS cases. Immunohistochemical stain for Cox-2 was interpreted as 1＋ (weak & focal) and 2＋ (diffuse), and the relationships between Cox-2 and ER, PR, Her-2, p53, Ki-67 and bcl-2 expressions were analyzed. Results: There was no significant difference of Cox-2 expression between IDC (148/353, 41.9%) and DCIS (38/82, 46.3%). Cox-2 (2＋) expression was more frequent in low grade than intermediate and high grade IDC, but the difference was not significant statistically (P=0.0833), and there were no significant differences of Cox-2 expression according to age, tumor size, nuclear grade, lymph node metastasis in IDC and DCIS cases. In IDC cases, Cox-2 (1＋ and 2＋) expression showed positive relationships with p53 (＋) and more than 10% of Ki-67 labeling index (P=0.0029, P=0.0015), and revealed tendencies of positive relationships with ER (＋) and bcl-2 (＋) (P=0.0750, P=0.0776). However, no significant relationship between Cox-2 and Her-2 expressions was recognized. In DCIS cases, Cox-2 (2＋) expression rate was increased in cases showing negative for Her-2 (P=0.0092) and positive for bcl-2 (P=0.0486). Conclusion: Cox-2 expression seems to be involved in the development of breast carcinomas, but not related to the invasiveness. Cox-2 expression, especially 2＋, in the DCIS cases suggest a possibility of less aggressive biological behavior.