Tissue stem cells are proposed to be the cell-of-origin of multiple cancer types. Determining the mechanisms important for stem cell transformation and tumour progression are critical for understanding these processes and guiding therapeutic development. My lab investigates stem cell transformation in the colon with the aim of identifying novel pathways that drive it. Growing evidence suggests alternative RNA splicing plays a key tumourigenic role and it dysregulation is common in cancer. We have recently identified a critical role for Rac1 during stem cell transformation, a gene that is hyperactivated via alternative splicing. We have also identified 100s of other aberrant splicing events during tumour initiation leading to the hypothesis that dysregulated RNA splicing is a critical mediator of colorectal stem cell transformation.