ID3 and malignant colon neoplasm: ID1 and ID3 can control colon cancer-initiating cells self-renewal through cell cycle inhibitor p21, preventing the accumulation of DNA damage. Silencing of ID1 and ID3 sentitizes the cells to oxaliplatin treatment. Involved in metastasis formation of gastric cancer. It can block B-cell development at the early pro-B cell stage.