Feline mammary tumors (FMT) are the third common tumors in cats after skin tumors and lymphomas. The main diagnostic tool of FMT is the imaging technique and histopathology that shows difficulties in application like time consuming and the high cost. The aim of the present investigation is to find a new easily, rapid and of low-cost diagnostic tool laboratory
evaluation of humoral immune response in normal and FMT cases. From the obtained results, it could be concluded that the using of autoantibodies is recommended as a rapid, easily and low-cost diagnostic tool of feline mammary tumor which is the human counterpart of breast cancer.