50% of all domesticated dogs die as a result of cancer. Of these, 71% account for mammary neoplasias. This comparative Analysis of human and canine breast cancer shows similarities in risk factors, anatomy, pathology and a comparative histological classification of breast neoplasias in humans and dogs. Most common risk factors are age, obesity, estrogen and progesterone, expressions of ER/PR, alterations of TP53,BRCA 1/2 and HER2. The proliferation markers PCNA, Ki67 and AgNOR are reliable predictors of malignancy in todays´ human and veterinarian oncology. A comparative histological approach shows striking similarities of some tumor entites (e.g. spindle cell carcinoma, osteosarcoma and inflammatory breast cancer), as well as dissimilarities in histology and origin of breast neoplasias between the species.
Improvement of therapeutic approaches, identification and prevention of risk factors and fusion of statistical and clinical genetics should be the aim of futural comparative investigations.
Breast cancer / comparative / risk factors / human / dog / age / obesity / hormones / classification / HER2 / BRCA / ER / PR