Tempus and Microsoft researchers report PRISM2 in Nature Medicine, a slide-level pathology foundation model trained on 2.3 million whole-slide images and 14 million question-answer pairs from about 700,000 reports. With prompt-based clinical dialogue, it matched or beat balanced accuracy of calibrated clinical-grade products for prostate, breast, and breast lymph node cancer detection without task-specific retraining. Embeddings also held up across diagnostic, biomarker, and survival benchmarks versus prior foundation models. Why it matters: language-supervised slides can approach specialist clinical detectors. Caveat: this is a research evaluation, not a cleared medical device for autonomous diagnosis.