Direct evidence that the VEGF-specific antibody bevacizumab has antivascular effects in human rectal cancer

Area of Science:

• Oncology
• Vascular Biology
• Pharmacology

Background:

• The role of vascular endothelial growth factor (VEGF) in tumor angiogenesis is well-established.
• However, the direct effects of VEGF blockade on the vascular biology of human tumors remain largely unknown.

Purpose of the Study:

• To investigate the rapid antivascular effects of VEGF blockade in human rectal carcinoma patients.

Main Methods:

• A single infusion of the VEGF-specific antibody bevacizumab was administered to rectal carcinoma patients.
• Tumor perfusion, vascular volume, microvascular density, interstitial fluid pressure, and circulating endothelial/progenitor cells were measured.
• Pericyte coverage of tumor vessels was assessed.

Main Results:

• Bevacizumab significantly decreased tumor perfusion, vascular volume, and microvascular density.
• A reduction in viable circulating endothelial and progenitor cells was observed.
• Increased pericyte coverage of tumor vessels was noted, alongside decreased interstitial fluid pressure.

Conclusions:

• VEGF blockade with bevacizumab demonstrates a direct and rapid antivascular effect in human rectal tumors.
• These findings support the therapeutic potential of targeting VEGF in cancer treatment.