Mammary tumour is the second most common cancer among dogs, just after skin cancer, accounting about fifty per cent of all tumours among dogs. Certain breeds like English Springer Spaniel, Boxer, Poodle, Bull Mastiff, German Shepherd, Cocker Spaniel, Dachshund and Fox Terrier dogs showed higher risk of incidence of mammary tumour, whereas certain other breeds like Collie, Shetland Sheep dog and Bernese Mountain Dog were considered to be at low risk. This breed predilection suggested that genetic factors play a role in canine mammary neoplasms. The role of numerous genes in canine mammary tumour (CMT) development and progression have been investigated, but the importance of the microenvironment is frequently disregarded as far as CMT is considered. Tissue inhibitor of metalloproteinase 2, commonly referred to as TIMP2, is one of several genes that influence the microenvironment of tumours. The interaction between Matrix Metalloproteinase 2 (MMP2) and TIMP2 is crucial for the invasion, development, and metastasis of tumours. The relative mRNA expression level of TIMP2 was examined in the current investigation in both CMT-affected and normal glands. A ten -fold reduced expression of TIMP2 was found in tumour samples than normal glands, which was statistically significant.