OpenAI said ChatGPT helped a woman discover her brain tumour had been misclassified for five years, with her diagnosis revised from glioblastoma to IDH-mutant astrocytoma, leading to a more accurate prognosis. A Zurich-based doctor disputed OpenAI's claim, saying, "Nobody missed anything." He added that the original 2020 diagnosis was correct under pre-2021 WHO tumour classification system.