MEN1 and leukemia: However, it is now well established that menin displays oncogenic effects in certain types of leukemia containing fusion MLL caused by chromosome translocation [24]. Dreijerink et al. found that the gene expression profile obtained after MEN1 silencing in normal mammary luminal progenitors was highly distinct from that found in ER-positive breast cancer MCF7 cells, suggesting that menin regulates different gene sets in normal mammary luminal cells versus ER-positive breast cancer cells [25].