ERBB2 and breast cancer: Additionally, entinostat converts immune resistant breast and pancreatic cancer into ICI-responsive tumors by decreasing the number of infiltrating regulatory T cells (Treg) and by suppressing granulocytic-MDSCs (myeloid derived immunosuppressive cells) in the tumor microenvironment (TME) of HER2/neu transgenic breast cancer and metastatic pancreatic cancer mouse models 10, 18.