Specifically, we found increased mRNA levels of the tumor suppressor gene Ecrg4, a factor downregulated in breast cancer tissue43, in post-pregnancy CAGMYC MECs (~6 Log2FoldChange), and downregulation of Bcl2L12 and Tbx3 mRNAs, factors whose low expression has been correlated with a senescence-like state44,45. Here, ECRG4 is linked to breast cancer.