Cancer is abnormal division of cells with the ability to invade other tissues. Cancer may be of more than 100 types depending on the origin of organ or cell types in which they start. Breast cancer begins in the cells of the lobule or ducts or in the stromal tissues .Genetic abnormality is also one of the main cause of breast cancer. Whereas prostrate cancer occurs due to mutation and may spread to other parts of body. Immunohistochemical and Immnofluorescence study of COX-2 expression in 29 cancer patient samples was performed. Cyclooxygenase (COX) is an angiogenic factor i.e., strongly related to inflammatory diseases & the development of cancer& metastasis in several cancers. We observed the higher percentage expression of COX-2 in breast & prostate carcinoma using IHC in comparison to IF. Positive immunoreactivity to COX-2 was noted 62.5% by IHC & 72.2% by IF. This study suggests the possible role of the COX-2 in breast & prostate cancer patients .