【Background and Purpose】Feline mammary tumor is known to be the third most common tumors in cats and high grade tumors but more effective treatment has not been established. The culture method of organoids is also familiar with a method which can maintain the epithelial tissue structures and the characteristic like stem cell by three-dimensional culture using a special culture medium. In previous study, we created the feline mammary tumor organoids from tissue extracted patients and revealed the suitable culture condition. Then, we compared original tissue and organoid, and clarified the relation with the pathological characteristics or the expressions of hormone receptor, the differences of anti-cancer drug sensitivity in each case. In this study, we compared the gene expression of feline mammary tumor organoids with normal mammary organoids and searched for new therapeutic targets.
【Method】RNA was extracted from organoids produced from normal mammary glands 3 cases and feline mammary tumor 6 cases, and RNA sequencing was performed using next generation sequencer.
【Result】In RNA sequencing, there were 112 significant differentially genes. 81 genes were markedly upregulated in feline mammary tumor, and 31 genes were in normal mammary glands. In addition, the expression of X genes related with estrogen receptor was significantly upregulated in feline mammary tumor. In GESA analysis, the pathways related to apoptosis, epithelial-mesenchymal transition, and estrogen were activated.
【Conclusion】In feline mammary tumor and normal mammary glands, genetic differences  was cleared and a strong association with estrogen was observed. We will plan to analysis the relationship between the gene identified in this study and feline mammary tumor, and the metabolite activity by metabolome analysis using feline serum, search for biomarkers lead to more earlier diagnosis.