Tumor cells that demonstrate autocrine VEGF signaling with co-expression of VEGF and its receptor VEGFR-2 on the same cell represent which mechanism of escape from normal growth control?

• A Evasion of apoptosis via BCL-2 overexpression
• B Self-sufficiency in growth signals (autocrine stimulation) ✓
• C Insensitivity to growth-inhibitory signals via PTEN loss
• D Limitless replicative potential via telomerase activation

Explanation

Autocrine VEGF signaling — where tumor cells both produce the ligand and express its receptor — exemplifies self-sufficiency in growth signals, one of Hanahan and Weinberg's original hallmarks of cancer. This differs from paracrine tumor angiogenesis, where VEGF acts on endothelial cells. PTEN loss confers growth-inhibitory signal insensitivity; BCL-2 prevents apoptosis; telomerase reactivation enables limitless replication.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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