Considering the IgE’s emerging anti-tumor activity [66–68], the first ongoing clinical trial using an IgE anti-tumor Ab in cancer patients (NCT02546921), the inverse correlation of serum IgE scores and risk of melanoma [32], the use of ultra-low IgE as a biomarker for cancer risk [69], and the associated usage of omalizumab, a monoclonal Ab that blocks IgE, with more cancer incidences [70], further definition of biological consequences and mechanisms of action for IgE in tumor immunity is of key importance. This evidence concerns the gene IGHE and cancer.