The use of H9, and H9-derived proteins, in experimental anti-tumour therapy provided solid proof of the concept of dimeric IL-2R super-agonism resulting in strong effector-biased immunological effects10,23,24 Combination of H9 mutations with replacements modulating the interaction with other IL-2R subunits gave rise to partial agonists, potent antagonists and selective agonists25–27. The gene discussed is IL2RA; the disease is neoplasm.