Angiogenesis is essential for tumor growth beyond 1–2 mm. The principal pro-angiogenic factor secreted by tumor cells that binds VEGFR-2 on endothelial cells to promote new vessel sprouting is:

• A Platelet-derived growth factor (PDGF)
• B Vascular endothelial growth factor A (VEGF-A) ✓
• C Fibroblast growth factor 2 (FGF-2/bFGF)
• D Angiopoietin-2 (Ang-2)

Explanation

VEGF-A (vascular endothelial growth factor A) is the master regulator of tumor angiogenesis. Hypoxia in the tumor microenvironment stabilizes HIF-1α (hypoxia-inducible factor), which transcriptionally upregulates VEGF-A. VEGF-A binds VEGFR-2 (KDR/Flk-1) on endothelial cells, driving proliferation, migration, and tube formation. Anti-VEGF therapy (bevacizumab) and VEGFR inhibitors (sorafenib, sunitinib) exploit this pathway. FGF-2 and PDGF also promote angiogenesis but VEGF-A is the dominant and most therapeutically targeted factor.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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