Potential markers for detection of circulating canine mammary tumor cells in the peripheral blood

Major discrepancies exist between histological predictions and actual metastatic potential of canine mammary tumors. Detection of circulating tumor cells (CTC) has a proven prognostic value for human breast cancer but similar markers for canine CTC are lacking. In the present study a panel of 16 human CTC markers was tested for their ability to specifically and sensitively detect canine carcinoma cells in peripheral blood. PCR assays for CK19, ERBB2, EGFR, CLDN7 and ELF3 were able to sensitively detect one carcinoma cell in up to 10(7) peripheral blood leukocytes. These CTC markers are thus candidate markers for identifying canine mammary CTC in the peripheral blood and may serve as prognostic factors for metastatic behavior in the future.