With the identification of tumor antigens, the host immune response to various types of cancers can now be studied with a high degree of specificity in large cohorts of patients, in the hope of correlating immunity with clinical events and defining immunotherapeutic strategies. Several antigens, such as NY-ESO-1, p53, or SOX2, have attracted attention because of their frequent spontaneous immunogenicity in cancer patients, notably in their ability to induce humoral responses. We describe in this chapter a simple implementation of a serological monitoring platform for autoantibody measurement in cancer patients, from production of recombinant antigens to ELISA testing and interpretation.