TET1 and cancer: It was also reported that knockdown of Tet1 or Tet2 minimally affects pluripotency gene Nanog mRNA expression, but knockdown of both Tet1 and Tet2 reduces Nanog mRNA expression significantly in mESCs [38] and that TET1, TET2, and TET3 are required for the expression of the tumor suppressor gene TCF21 mRNA in cancer cells [39].