Using affinity matrices, we evaluated the purification of two recombinant IgE antibodies: the mouse/human chimeric antibody CSPG4-IgE recognizing the melanoma-associated antigen Chondroitin Sulfate Proteoglycan 4 and the humanized antibody HER2-IgE recognizing the breast cancer-associated antigen Human Epidermal Growth Factor Receptor 2. The gene discussed is ERBB2; the disease is breast carcinoma.