β2-microglobulin has a different regulatory molecular mechanism between ER + and ER − breast cancer with HER2 −

Background Previous studies have demonstrated that β2-microglobulin (β2M) promotes the growth and survival of a variety of cancer cells and has different regulatory effects on the expression of Bcl-2 and HER2 in HER2− breast cancer cells. However, β2M-mediated signaling in ER+ and ER− breast cancer with HER2− remains unclear.