Immunohistochemical Expression of Cd 44, Cd24 and Esa in Canine Mammary Tumours

Identification of Cancer stem cell lineage subpopulations of tumor cells within the tumor mass offer to identify targets for therapeutic interventions and a better understanding of carcinogenesis. The main objective of this study was to evaluate the prognostic value of cancer stem cell lineage markers i.e., CD44, CD24 and Epithelial specific antigen (ESA) in canine mammary tumours using triple immunohistochemistry. A total of 40 surgically excised tissue samples of canine mammary tumours were obtained during the eight month study period. These tumors were classified according to WHO classification of mammary tumors of dog (2002), as Carcinoma – tubular, Carcinoma – Papillary cystic, Squamous cell carcinoma and Carcinosarcoma with tumor grades I & II respectively. Of 40 samples, 24 selected cases were subjected to triple immunohistochemistry using antibodies against CD 44, CD 24 and ESA. Two cases were positive for cancer stem cell phenotype i.e., CD44+/CD24-/low/ ESA+ showing colocalized expression of CD44, epithelial specific antigen (ESA) with membranous staining and absence or isolated staining for CD24, which correlated with both the cases showing distant metastases and reduced average survival period of 122 days, indicating poor survivability and distant metastasis. CD44+/CD24-/ESA+ expression was seen in carcinosarcoma (Grade I) indicating an epithelial mesenchymal transition and could favor metastasis. triple immunohistochemical expression of cancer stem cell phenotype i.e., CD44+/CD24-/ESA+ favored distant metastasis with poor prognosis and could be used as a prognostic indicator in canine mammary tumors as evident from this study.