Abstract 4511A: KMO as a novel diagnostic and prognostic biomarker in canine mammary gland tumors

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL The purpose of this study is to verify the candidate genes KMO associated with the progressive growth of canine transmissible venereal tumor (CTVT) in clinical application as biomarkers for spontaneous canine mammary gland tumors (cMGT). Canine mammary gland tumor shares similar characteristics with human breast cancer in histopathology and biological behavior. Both of them are hormonal-dependent, and they have similar genetic aberrations, signature profiles and cell signal pathways. These facts suggest that canine mammary gland tumor could be a referable tumor model for human breast cancer research. Our previous study has shown screening the gene expression of kynurenine 3-monooxygenase (KMO), an enzyme involved in tryptophan metabolism, could predict tumor malignancy and survival time of cMGT-suffering dogs. Here we intend to confirm KMO as a real cancer biomarker by investigating its protein expression in a serious of 54 cMGT cases, 29 of them were benign and 25 malignant collected at the Veterinary Hospital of National Taiwan University (VHNTU) with immunohistochemistry. The results indicated that KMO discriminated malignant cMGTs from benign ones, and about 73.3% of malignant cMGT showed strong expression of KMO. In addition, patients with strong KMO expression had markedly lower overall survival rate than those with negative or weak ones. Comparing to KMO investigations, increasing Human epidermal growth factor receptor 2 (HER-2) manifestation was also shown to correlate with tumor size and cMGT stages. A positive correlation between KMO and Ki-67 expression was found in our cMGT cases and it suggests KMO may contribute to tumor development by promoting cell proliferation. This study demonstrated KMO as a potential biomarker in tumor diagnosis and prognosis. It might offer new perspectives for clinical applications of cMGT and perhaps lead to advance in human breast cancer research. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4511A. doi:1538-7445.AM2012-4511A