Figure 2.

FRα‐positivity in blood or tumor does not influence basophil activation by anti‐cancer IgE. Circulating FRα and anti‐FRα autoantibodies may form immune complexes with MOv18 IgE, triggering basophil activation (A). No basophil activation was measured following MOv18 IgE stimulation in blood from the 71% of patients with FRα‐positive tumor (B) (representative FRα‐stained paraffin‐embedded tumor, C). Despite detectable FRα or anti‐FRα IgG autoantibodies in a proportion of patients, MOv18 IgE triggered basophil activation in one blood sample (D‐G). In the 9% of patients with both FRα and anti‐FRα IgG autoantibodies, no basophil activation by MOv18 IgE or control IgE was observed (H)