The relative expression levels of the tumour marker P53 mRNA in the canine mammary carcinomas are highly significant (p < 0.001) when compared with those in the benign mammary tumours and the paraneoplastic controls, but the differences between the two are not significant (p > 0.05) when the benign mammary tumours are compared with the paraneoplastic controls. Here, TP53 is linked to neoplasm.