ID1 and cancer: Knockdown of both NELFA and NELFE inhibited the proliferation of the TetOff cells and reduced the expression levels of most cancer stemness-related genes including LGR5 and ID1, whereas KRT20 and MUC2 expression levels increased (Fig. 5B and Supplementary Fig. 6A, B), suggesting that both NELF and PAF1C contribute to LGR5 expression and maintenance of colon cancer stemness.