Overexpression of Heat Shock Protein 90α in Canine Mammary Tumors.

Canine mammary gland tumor is the most patronize and dangerous type of tumor diagnosed by histopathology and requires a surgical approach. Hsp90α, a member of the heat shock protein-90 family that found to be over-expressed in breast cancer. However, biological function is unknown in the canine mammary tumor. So, we focused on studying the expression of hsp90AA1 and protein in canine mammary tumor (CMT) tissue. Expression of hsp90AA1 mRNA and protein were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC), respectively. High levels of hsp90AA1 mRNA expression (4.613 ± 0.49 times) were observed in CMT compared to age and breed-matched healthy controls. Further, expression of hsp90α protein was detected in paraffin-embedded mammary tumor tissues from the same subjects by IHC. A high level of hsp90α expression was scored in 75% of the CMT subjects. Moreover, no significant differences in IHC score and qRT-PCR score with respect to CMT histotypes were observed, indicating that Hsp90AA1 over-expression occurred irrespective of CMT types or grades.