KRT20 and cancer: Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) analyzes showed that our CCOs mimicked the tissue architecture of their original cancers and retained the expression of colorectal adenocarcinoma markers [5] cytokeratin 20 (CK20) and caudal-type homeobox 2 (CDX2) (Fig. 1A).