Abstract

Gene expression changes in tumour cells underlie important aspects of cancer biology, can aid in prognostication of cancers, and form the basis for the application of targeted cancer therapies. Understanding which changes are the most clinically relevant is challenging due to the genomic instability of cancers, the complexity of signalling pathways, and heterogeneity within tumours and between patients. The approach we have taken is to leverage both the similarities and the differences across mammalian species to investigate changes in gene expression in osteosarcoma and mammary carcinoma. Changes that define molecular subclasses with clinical relevance in human cancers may also have clinical relevance in canine cancers. Because expression changes that are common across species are likely to reflect biological processes that are fundamental to cancer biology, they may also represent the best molecules for targeted cancer therapies.