TET1 and neoplasm: In the MMTV-Py-MT model (luminal tumors), qRT-PCR revealed low levels of exon 1 (Tet1 long isoform) in tumor tissue and a twofold increase expression level of the shorter Tet1 gene in tumor tissue suggesting the possible relevance of this isoform in breast tumorigenicity in specific tumor types (Figure 4C).