In this model, oncogenic KRAS was found to be involved in the inhibition of luminal apoptosis, impairment of epithelial cell polarity and downregulation of DNA repair genes including TP53 and BRCA2 in a 3-D specific manner [5], suggesting that this model could mimic the in vivo growth of the colonic epithelium and would be useful for determining the critical genes involved in CRC development through oncogenic KRAS-mediated signals in vivo. The gene discussed is KRAS; the disease is colorectal carcinoma.