-TET1, TET2, and TET3 transcript levels were significantly reduced in tumors as compared to control tissues.-High TET2 mRNA levels in histopathologically normal tissues from CRC patients associated with favorable overall survival and disease-free survival.-In tumor samples, promoter hypermethylation was found only in TET1 (12/113 = 10.6%) but not in TET2 or TET3. The gene discussed is TET1; the disease is neoplasm.