CEACAM5 and neoplasm: Recombinant S. cerevisiae can be used as a non-pathogenic and non-toxic vaccine vehicle to induce immune responses to foreign tumor-associated antigens, so vaccination with this heat-killed recombinant yeast expressing the human carcinoembryonic antigen (CEA) induces CEA-specific immune responses, reduces tumor burden, and leads to increasing overall survival in CEA-transgenic mice [189].