In addition to the differences in histology, at the cellular level, loss of differentiation involves loss of cell-cell contacts14 and cell polarity15, while at the molecular level, poorly differentiated tumours display reduced expression of drivers (e.g., CDX2)16 and markers (e.g., VIL1 and KRT20)17,18 of colonic differentiation. The gene discussed is KRT20; the disease is neoplasm.