Knowing that both DiD + PyMT-Bo1 cells and dormant D2.0R cells exhibit a similar gene expression signature in vivo and that ectopic expression of Cfh, Gas6, Ogn or Mme failed to induce a dormant phenotype in PyMT-Bo1 cells, we next asked if those genes were necessary for maintaining breast cancer cell dormancy. This evidence concerns the gene MME and breast cancer.