Conversely, complement-activating immunotherapeutic complexes (CoMiX) targeting HER2-positive tumor cells via the alternative pathway (FHR4-mediated) or the classical pathway (tri-Fc dimer–mediated) significantly enhance C3b/C5b-9 deposition and CDC, effectively suppressing tumor growth even in resistant models (85). The gene discussed is C3; the disease is neoplasm.