Molecular Targeted Therapy in Solid Tumors: Mechanisms, Resistance, and Emerging Strategies

This chapter provides a comprehensive review of molecularly targeted therapies in solid tumors, examining the biological rationale for targeting oncogenic drivers such as receptor tyrosine kinases, RAS/MAPK, and PI3K/AKT/mTOR pathways. It critically evaluates approved targeted agents across major tumor types, with particular emphasis on mechanisms of primary and acquired resistance and the evolving strategies — including combination regimens and next-generation inhibitors — designed to overcome them.