BRAF and breast angiosarcoma: It remains unclear whether different crypt progenitors and/or mature cell types are able to dedifferentiate to a foetal-like state in response to BRAF activation, or whether homeostatic colonic crypt subpopulations, such as the revival stem cells, acquire Braf mutation and initiate serrated tumorigenesis independently of Wnt signalling: the answer awaits lineage-tracing and single-cell genomics approaches in our BA model.