ANXA2 and breast cancer: The endoplasmic reticulum aminopeptidase 2 (ERAP2) has been identified by our group as an EpCAM‐associated protein,6 and here we continue this effort and present another novel finding that Annexin A2 (ANXA2) is a potential interacting partner of EpCAM in the EpCAM+ ERα+ breast cancer cells.