Compounds from mushrooms like reishi (Ganoderma lucidum) and turkey tail (Trametes versicolor) can stop cancer cells from growing while sparing healthy ones. In lab tests, oyster mushroom (Pleurotus ostreatus) extracts triggered up to 70% tumor reduction in mice and halted cell growth in breast, colon, and prostate cancers by inducing apoptosis and arresting the cell cycle. These β-glucans, lectins, and polysaccharides are emerging as powerful natural allies in cancer prevention and treatment.