Edible and medicinal mushrooms influence tumor biology through immune activation, gut microbiome shifts, antioxidant defense, and regulation of pathways like NF-κB, MAPK, and apoptosis that control cancer cell growth and survival. Compounds such as β-glucans and triterpenes can enhance natural killer cell activity, improve cytokine signaling, and help the body better recognize and attack abnormal cells, while also reducing treatment-related inflammation and oxidative stress.