Targeting breast cancer stem cells by a ROR2 specific antibody

ROR2 is a type I orphan-receptor tyrosine-kinase-like membrane protein. Its expression level is decreased after birth and barely detectable in adulthood. However, it is re-expressed by various cancer cells and is negatively correlated with patients' survival. The role of ROR2 in breast cancer is still unknown.This study demonstrated that ROR2 activates RhoA GTPase, and induces EMT in breast cancer. In addition, ROR2 is enriched in breast CSCs and required for maintaining the stemness features of CSCs. We developed a ROR2 specific antibody that inhibits breast cancer primary tumor growth and metastasis through targeting CSCs. mRNA profile of breast cancer PDXs from NCG mice treated with ROR2 antibody, B16 or human IgG of irrelevant specificity.