CEA-based vaccines.

Carcinoembryonic antigen (CEA), the first tumor-associated antigen to be described, was cloned in 1987 and is expressed on nearly 50% of all human tumors. The identification of T-cell specific epitopes within the coding region of the CEA protein has led to the development of various vaccine strategies that target CEA and CEA-expressing tumors. These vaccines have shown evidence of therapeutic effectiveness in animal models and are being evaluated in early phase clinical trials. Although trials are not designed to elucidate clinical responses, they have provided important information about the ability of individual vaccines to induce CEA-specific immune responses through the use of newer in vitro monitoring assays. Continued clinical testing in patients with less advanced disease and the administration of vaccines in combination with other standard therapy will help define the role of CEA-based vaccines in the treatment and prevention of human cancer.