The increased expression of TKT found in mammary tumors and in hyperplastic lesions of the dog appears to be substantially in agreement with those reported in recent studies carried out in human and veterinary medicine, in which there was an increased expression of TKT in cancer tissues and in progestin-induced canine mammary hyperplasia compared to non-tumor tissues, respectively [12, 36, 37]. Here, TKT is linked to cancer.