Direct inhibitors function by binding to specific molecules within cancer cells, thereby preventing these molecules from performing their normal biological functions. For instance, many cancers rely on overactive signaling pathways such as the PI3K/AKT/mTOR pathway or the Ras/MAPK pathway to proliferate. Direct inhibitors can block these pathways, effectively stalling tumor growth. Some well-known examples include tyrosine kinase inhibitors and proteasome inhibitors.
