['The aim of this study was to evaluate the expression of cyclooxygenase-2 in human breast cancer using immunohistochemistry and to determine whether the expression of cyclooxygenase-2 is associated with clinicopathological factors in invasive ductal breast carcinoma.', 'Cyclooxygenase-2 expression was investigated by immunohistochemistry in 30 invasive ductal breast carcinoma specimens and relationships between cyclooxygenase-2 expression and age, histological grade, histological type, nodal status, and hormone receptor status were evaluated.', 'Cyclooxygenase-2 expression was found in 56.7% of the tumor samples and was related to histological grade (P<0.01) and histological type (P<0.001).'] Is elevated cyclooxygenase-2 expression associated with histological grade in invasive ductal breast carcinoma?