To elucidate whether the presence of a specific Tet1 isoform is relevant to breast tumorigenesis, we tested the expression of the short and full length Tet1 in normal and tumor mammary tissues obtained from either p53 and WWOX single and double knockout mice, which give rise to basal triple negative mammary gland tumors (from Prof. Rami Aqeilan, Hebrew University) or from an MMTV-PyMT transgene mouse model that give rise to luminal tumor type (RNA provided by Dr. Itay Ben-Borath, Hebrew university). Here, TP53 is linked to neoplasm.