[89Zr]Zr-ERY974, a bsAb targeting CD3ε on T-cells × GPC3, showed high specific uptake in GPC3-positive ovarian cancer xenografts ingrafted with immune cells compared to xenografts in immunodeficient mice, highlighting the potential value of such probes in immunotherapy response monitoring (372). The gene discussed is GPC3; the disease is ovarian carcinoma.