Gastric cancer, one of humanity's most lethal malignancies, has long resisted the promise of immunotherapy in a significant subset of patients whose tumors carry a genetic feature that renders them nearly invisible to immune attack. A new study published in Nature traces a precise molecular mechanism by which three established drugs — 5-fluorouracil, cisplatin, and apatinib — can compel these resistant cancer cells to reveal themselves, upregulating the very protein that immunotherapy is designed to target. The discovery does not yet change the clinic, but it changes what the clinic can imagin