MDC1 and breast cancer: Interestingly, the same study demonstrated that the over-expression of MDC1-AS1 promotes the upregulation of the MDC1 coding gene both at RNA and protein levels, suggesting that MDC1-AS1 has an inhibitory role on BC cells proliferation through its upregulation of the tumor suppressor gene MDC1. While this subject is still under investigation, the easiest explanation found so far is that, in some way, this antisense RNA can stabilize the MDC1 mRNA.