MNT and breast adenocarcinoma: Mnt can serve as a tumour suppressor, as tissue-specific deletion of Mnt in mice resulted in mammary adenocarcinomas and T-cell lymphomas.8, 25, 47 Conversely, Mnt overexpression mimicked Myc knockout, producing growth defects and embryonic lethality25 as well as reducing cell cycle entry and proliferation of MEFs in vitro.