Role of CD24 in HER2-positive breast cancer.

Abstract

e11572 Background: Human epidermal growth factor receptor 2 (HER2) is a transmembrane kinase receptor, which promotes the RAS/RAF/MEK/ERK and the PI3K/AKT/mTOR pathways. The standard treatment for HER2-positive breast cancer is a combination of chemotherapy plus an anti-HER2 agent, such as trastuzumab and lapatinib. HER2-positive breast cancers are predominantly positive for CD24, which is a glycosyl phosphatidylinositol (GPI)-anchored membrane protein. Overexpression of CD24 in breast cancer is associated with a poor prognosis. We hypothesize that the co-expression of HER2 with CD24 is associated with the therapeutic resistance of HER2-positive breast cancer cells. Methods: We established HER2-expressing cell lines by introducing a wild type HER2 gene into MDA-MB-231 triple-negative (ER-/PgR-/HER2-) breast cancer cells. We used the HER2-positive breast cancer cell lines BT-474, HCC202, SKBR3, and HCC1569. To investigate the relevance of CD24 expression in HER2-positive breast cancer, we analyzed HER2 and...