Feline Mammary Tumors Show Altered COX-2 and BRCA1 Expression

Cancer is the one of the main causes of death in cats and dogs, while it is the second most cause of deaths in humans. In third world countries, less attention is paid to the health of pets. The genes (COX-2 and BRCA1) are selected to study the mutation and gene expressional profiling (qPCR, Real Time PCR) in mammary tumor of cats. Being mammals, cats are studied as a model as they may suffer from cancer in the same way as that of humans. Five (n=5) mammary tumors and twenty five (n=25) normal mammary tissues are collected from different cats respectively. All samples were collected from Lahore city, Punjab, Pakistan. High grade negative gene expression of BRCA1 was observed in all mammary tumors. Here, we found that 40% of the mammary tumors showed upregulation of COX-2 gene with fold changes i.e. 1.76 and 1.84, respectively. While remaining mammary tumors showed positive behavior of COX-2 gene expression, but it was down regulated as compared to normal samples included in the study with fold changes i.e. 0, 0.76 and 0.82. Sequencing of whole coding region of COX-2 gene (1-10 exons) and the hot spot 5’ (N terminal, i.e. 1, 2, 12 exons) and 3’ region (C terminal, 18, 19, 20, 21, 22 exons) of BRCA1 gene which comprised of 1812bp, 1128bp and 2024bp, respectively was also performed. There was not a single mutation observed in the selected regions. In conclusion, it was observed that the drastic reduction in BRCA1 gene expression and over expression of COX-2 may have a role in mammary tumor of cats. The fold change of COX-2 gene in tumors has been associated with the extent of aggressive tumor’s type. However, the mechanism behind the abnormal function of these genes is not clear yet and further studies are required.