Glioblastoma Recurrence after Cediranib Therapy in Patients: Lack of "Rebound" Revascularization as Mode of Escape
Emmanuelle di Tomaso1,6, Matija Snuderl2, Walid S. Kamoun1, Dan G. Duda1, Pavan K. Auluck2, Ladan Fazlollahi2, Ovidiu C. Andronesi3, Matthew P. Frosch2, Patrick Y. Wen4, Scott R. Plotkin5, E. Tessa Hedley-Whyte2, A. Gregory Sorensen3, Tracy T. Batchelor5, and Rakesh K. Jain1
Authors' Affiliations: Departments of 1 Radiation Oncology and 2 Pathology (Neuropathology), and 3 Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Massachusetts Institute of Technology, 4 Department of Adult Oncology, Dana-Farber Cancer Institute, and 5 Stephen E. & Catherine Pappas Center for Neuro-Oncology, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, 6 Current affiliation: Novartis Institutes for BioMedical Research, Cambridge, MA.
Corresponding Author: Rakesh K. Jain, Steele Laboratory, COX-734, Massachusetts General Hospital, 100 Blossom Street, Boston, MA 02114. Phone: 617-726-4083; Fax: 617-724-1819. E-mail: Jain@steele.mgh.harvard.edu
Recurrent glioblastomas (rGBM) invariably relapse after initial response to anti-VEGF therapy. There are 2 prevailing hypotheses on how these tumors escape antiangiogenic therapy: switch to VEGF-independent angiogenic pathways and vessel co-option. However, direct evidence in rGBM patients is lacking. Thus, we compared molecular, cellular, and vascular parameters in autopsy tissues from 5 rGBM patients who had been treated with the pan-VEGF receptor tyrosine kinase inhibitor cediranib versus 7 patients who received no therapy or chemoradiation but no antiangiogenic agents. After cediranib treatment, endothelial proliferation and glomeruloid vessels were decreased, and vessel diameters and perimeters were reduced to levels comparable to the unaffected contralateral brain hemisphere. In addition, tumor endothelial cells expressed molecular markers specific to the blood–brain barrier, indicative of a lack of revascularization despite the discontinuation of therapy. Surprisingly, in cediranib-treated GBM, cellular density in the central area of the tumor was lower than in control cases and gradually decreased toward the infiltrating edge, indicative of a change in growth pattern of rGBMs after cediranib treatment, unlike that after chemoradiation. Finally, cediranib-treated GBMs showed high levels of PDGF-C (platelet-derived growth factor C) and c-Met expression and infiltration by myeloid cells, which may potentially contribute to resistance to anti-VEGF therapy. In summary, we show that rGBMs switch their growth pattern after anti-VEGF therapy—characterized by lower tumor cellularity in the central area, decreased pseudopalisading necrosis, and blood vessels with normal molecular expression and morphology—without a second wave of angiogenesis. Cancer Res; 71(1); 19–28. ©2011 AACR.
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