PF-431396 is a potent inhibitor of focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (Pyk2), enzymes involved in cell adhesion, migration, and survival. It is primarily used in research settings to study signaling pathways related to cancer progression, metastasis, and tumor cell motility. By inhibiting FAK and Pyk2, PF-431396 disrupts integrin-mediated signaling, making it a valuable tool for investigating the role of these kinases in tumor microenvironment interactions and angiogenesis. The compound has shown potential in preclinical studies for enhancing the efficacy of chemotherapy and targeted therapies, especially in solid tumors where FAK overexpression is linked to poor prognosis. It is also used to explore mechanisms in inflammatory diseases and immune cell regulation due to its effects on cell adhesion and cytokine signaling. Its selectivity and cell permeability make it suitable for in vitro and in vivo experimental models, though it is not used clinically.