Poster for the 2021 CRUK Cancer Evolution Symposium.Colorectal cancer (CRC) tumours present as a heterocellular setting where the colon epithelia harbouring oncogenic mutations interacts with the surrounding stromal and immune compartments. Despite epithelial organoids being used to model CRC there is a lack of complex coculture systems that also model the tumour microenvironment (TME). Here we present such a system, able to model both the oncogenic and microenvironmental axes, and report how scRNA-seq analysis reveals that stromal cells modulate differentiation in normal colonic epithelia but fail to do so in the altered CRC organoids.