FPR1 and ovarian carcinoma: The BAT assay is used to monitor for hypersensitivity to the first-in-class IgE immunotherapeutic as part of its clinical development.9 15 21 Whole blood samples from ovarian cancer patients were incubated with either stimulation controls: anti-FcεRI antibody to crosslink the IgE receptor, fMLP (N-Formylmethionyl-leucyl-phenylalanine), a polyclonal activator of human basophils, or polyclonal anti-human IgE to cross-link endogenous IgEs already bound to the surface of human blood basophils.