Characterising transcriptional changes throughout c-MYC-driven tumorigenesis in the mammary gland (MMTV-cMYC mouse model)

c-MYC oncogene is one of the driver lesions in many types of cancer. Among breast cancers, triple negative subtype (TNBC) is characterised by high aggressivness and is associated with high transcriptional activity of MYC. MMTV-cMYC mouse model, in which ectopic expression of c-MYC is driven by mouse mammary tumour virus promoter, is a widely used model of MYC-driven breast cancer. MMTV-cMYC mice develop tumours in the mammary gland(s) at ages ranging from 6 to 10 months. MYC regulates activity of multiple processes including cell cyle, proliferation, metabolism, protein translation, inflammation and apoptosis among others. Previous studies demonstrated that MMTV-cMYC tumours are very heterogeneous. However, how different procecesses regulated by MYC contribute to different steps of the transformation process and tumour development is not known. To evaluate how the expression of genes changes from the initiation of transformation process by ectopic expression of c-MYC in mammary gland epithelial cells to the development of tumours, we perfomed RNAseq analysis of tissues collected from mammary glands and tumours of MMTV-cMYC mice of different ages. Wild type age-matched littermates were used as controls.