Immunohistochemical basis for adjuvant anti-angiogenic targeted therapy for renal carcinoid: Initial case report

Objectives: To evaluate the immunohistochemical profile of a carcinoid (low grade neuroendocrine tumor of the kidney) from a patient with lymph node positive disease who remains disease free for 31 months after radical nephrectomy, lymph node dissection, and adjuvant therapy with sunitinib malate. Methods: Immunohistochemical staining was performed for chromogranin, synaptophysin, CD31, VEGF, HIF-1 alpha, HIF-2, and Glut-1. Staining was evaluated in 3 high-power fields and samples scored as strongly positive (3+), moderately positive (2+), weakly positive (1+), or negative (0). A clear cell renal cell carcinoma was used as positive control. Results: Immunohistochemical staining was strongly positive VEGF, weak to moderately positive for HIF-2, and negative for HIF-1 alpha and Glut-1. Conclusions: Our case of primary renal carcinoid stained intensely for VEGF and HIF-2, consistent with a VHL-HIF1-HIF2-Glut1 independent pathway for VEGF activation. These data suggest that like other neuroendocrine tumors, primary renal carcinoid is a potential target for anti-angiogenic therapy with sunitinib. (C) 2011 Elsevier Inc. All rights reserved.