Abstract
Background and objectives: To date, many tumor markers have been used to predict prognosis and therapeutic response in patients with breast cancer. The well established and routinely applied tumor markers are the estrogen-receptor, progesterone-receptor and Her2/neu-receptor. In the current study, we aimed to highlight any association of the proliferation index (Ki67) in breast infiltrative duct carcinoma with the tumor grade, tumor size and nodal status in addition to hormone receptor status. Tissue sections were stained immunohistochemically for Ki67 nuclear antigen, estrogen, progesterone and Her2/neu receptors using an automated Dako machine (Dako Denmark. There was a significant inverse relationship of Ki67 levels with ER and PR, while values were directly proportional to the tumor grade and Her2/neu status. No significant association was found between Ki67 and size of tumor or nodal status. Ki67 immunoexpression may offer an independent predictive tumor marker and for routine application in cases of breast cancer.