NOG and cancer: On day 6 in culture, single epithelial cells subjected to 3D culture with Noggin, FGF-7, FGF-10, sonic hedgehog agonist, and EGF (NFFSE medium) and with atelocollagen, the defined type I collagen that lacks telopeptide regions and thus can be used for clinical application (unlike cancer-derived Matrigel), formed round-shaped spheroids of varying sizes with the highest spheroid-forming efficiency at 32.0 ± 9.8% and an amplification rate of 198.0 ± 22.3-fold (Fig. 1b,d, Supplemental Fig. S1a).