The sensitivity of clonal abundances to biases in SC loss and replacement provides a potential therapeutic screening strategy for further exploration in which using a simple histochemical technique to quantify the ratio of partial to fixed clones and the identification and quantification of stem cell expansion and crypt fission events could provide evidence for early changes in colorectal crypt SC homeostasis prior to overt tumour initiation, particularly in those patients with germline APC mutations. This evidence concerns the gene APC and neoplasm.