Forty-eight canine mammary tumours (CMT) diagnosed at the Histopathology Laboratory, Faculty of Veterinary Medicine,
Universiti Putra Malaysia, were reviewed retrospectively. Two control groups, one comprising all other cases involving female dogs
and another group comprising only cases of neoplasia involving female dogs diagnosed in the laboratory over the same period of
time were used for comparisons in this study. Fisher’s exact test and logistic regression were used to determine association between
the factors and the risk of CMT. Thirty-nine (81.3%) of the tumours were diagnosed as adenocarcinoma, 8.3% (n=4) each, were the
diagnoses for squamous cell carcinoma and mixed cell tumour. Adenoma had 2.1% (n=1). The prevalence of canine mammary gland
tumours in this study is 39%. When CMT cases were compared with all other cases, significant association was observed with adult
dogs (p = 0.032, logistic regression 0.012) and intact dogs (p = 0.009, logistic regression, 0.003). When CMT cases were compared
with neoplasia cases, significant association was observed with pure breeds (p = 0.025) and intact dogs (p = 0.000034, logistic
regression 0.00042). This study found that pure breed dogs, intact dogs and older dogs ( > 5years) have higher odds of having CMT
in Malaysian dog population.
MicroRNAs (miRNAs) have important roles in all biological pathways in multicellular organisms. Over 1,400 human miRNAs have been identified, and many are conserved among vertebrates and invertebrates. Regulation of miRNA is the most common mode of post-transcriptional gene regulation. The miRNAs that are involved in the initiation and progression of cancers are termed oncomiRs and several of them have been identified in canine and human cancers. Similarly, several miRNAs have been reported to be down-regulated in cancers of the two species. In this review, current information on the expression and roles of miRNAs in oncogenesis and progression of human and canine cancers, as well the roles miRNAs have in cancer stem cell biology, are highlighted. The potential for the use of miRNAs as therapeutic targets in personalized cancer therapy in domestic dogs and their possible application in human cancer counterparts are also discussed.