CEACAM5 and neoplasm: For example, docetaxel in combination with cancer vaccines has been shown to enhance activated CTL killing by increasing the tumor cell permeability and thus increasing tumor susceptibility to granzyme-B dependent killing, thereby potentially releasing new TAAs in the environment.17 43 The recalcitrance of the 4T1 model to vaccine and immunotherapy in general may explain the decreased ability of hexatherapy to promote vaccine and cascade antigen-specific T cells in the 4T1 model compared with the MC38-CEA model.