We present the results of a retrospective matched-control and cohort evaluation of cancer patients participating in clinical trials of cetuximab, designed to (1) evaluate whether the presence of pretreatment IgE antibodies against cetuximab is associated with SIR during initial infusion and (2) evaluate the positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of the Phadia ImmunoCAP Specific IgE System, which is designed to detect anti-cetuximab IgE using ImmunoCAP Allergen c360, Cetuximab. The gene discussed is IGHE; the disease is cancer.