Circulating level of heat shock protein 27 is elevated in dogs with mammary tumors

In the current study, we have synthesized canine recombinant Hsp27 in E. coli and raised hyperimmune serum against the protein in mice. Using the hyperimmune serum, an indirect ELISA was developed to estimate circulating levels of Hsp27 in dogs with various types of mammary neoplasia and to compare their levels with those of tumor-free apparently healthy dogs. The developed assay had a high specificity (83.3%) and sensitivity (96.6%) for a cut-off value of 0.45 with respect to histopathological examination in discriminating healthy dogs from those bearing mammary tumors. Serum Hsp27 levels were found to be significantly elevated in tumor subjects (20.33 ± 1.23 ng/ml) as compared to healthy controls (6.56 ± 0.51 ng/ml) and the increase in the Hsp27 levels was irrespective of mammary tumor histotypes. However, dogs with grade-II tumors had higher Hsp27 levels as compared to grade-I types. Therefore, Hsp27 can be exploited as one of the 'neoplastic signatures' of canine mammary tumors.