Identification of Six Potential Markers for the Detection of Circulating Canine Mammary Tumour Cells in the Peripheral Blood Identified by Microarray Analysis

SummaryThe presence of circulating tumour cells (CTCs) in the peripheral blood is a prognostic factor for survival of human breast cancer patients. CTCs in the peripheral blood of dogs with mammary tumours have not been reported definitively. The present pilot study identifies mRNA markers for CTCs by comparing the transcriptome of canine mammary carcinoma cell lines CMM26 and CMM115 and peripheral blood leucocytes (PBLs). Genes with a 200-fold or higher mRNA expression in carcinoma cell lines were tested for specificity and sensitivity to detect CTCs using reverse transcriptase polymerase chain reaction (PCR). Six mRNA markers, AGR2, ATP8B1, CRYAB, F3 IRX3 and SLC1A1 were expressed in cell lines, but not PBL. All PCRs were able to detect one carcinoma cell admixed in 106 or more PBLs. The six mRNA markers may be suitable for detection of canine mammary CTCs and allow the analysis of their spatiotemporal distribution in dogs with mammary tumours.