Tissue was fixed using 10% buffered formalin solution. Five-micrometer sections of formalin fixed paraffin-embedded specimens were cut and immunohistochemical staining was performed using the peroxidase anti-peroxidase method. Fresh citric buffer solution of pH 6 was used for all markers except estrogen receptor (ER) and Wilms' tumor 1 (WT1) (pH 2.5). Antigen retrieval was carried out using a microwave oven. Next a peroxide block was used to prevent background non-specific staining due to endogenous peroxidases. This was followed by the addition of the primary and secondary antibodies and subsequently the addition of the chromogen, 3,3Diaminobenzidene. Slides were counterstained using H and E, stain. We used a panel of six markers including cytokeratin7 (CK7), CK20, carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), ER and WT1 to differentiate between primary and metastatic ovarian tumors