[27] Beta-Adrenergic Receptor Expression in Adult Vascular Tumors.

Karen M Chisholm, Kay W Chang, Mai T Truong, Shirley Kwok, Rob West, Amy E Heerema-McKenney. Stanford University School of Medicine, CA; Cleveland Clinic, OH

Background: Propranolol has been found to successfully cause regression in complicated infantile hemangiomas (IH). The B-adrenergic receptor antagonist is thought to lead to vasoconstriction by its downstream effect on nitric oxide, block angiogenesis by its downstream effect on vascular endothelial growth factor (VEGF), and lead to apoptosis. We recently reported expression of B-2 adrenergic receptor (B2-AR) its phosphorylated form (B2-ARP) in a case of IH responding to propranolol treatment (J.Pediatr. 156:335; 2010). We now explore the expression of B-adrenergic receptors on a variety of vascular lesions in adults utilizing a tissue microarray (TMA).
Design: A vascular tumor TMA containing 88 lesions (littoral cell angioma (7), epithelioid hemangioendothelioma (15), angiosarcoma (47), intimal sarcoma (5), Kaposi sarcoma (5), spindle cell hemangioma (5), and one case each of hemangioendothelioma of bone, retiform hemangioendothelioma, sinonasal hemangiopericytoma and lymphangioleiomyomatosis), was immunohistochemically stained for B2-AR, B2-ARP, and B3-AR, and scored for the intensity of endothelial cell expression as negative, weak positive or strong positive.
Results: Strong expression of B2-AR was consistently present in all cases of intimal sarcoma, spindle cell hemangioma and the bone hemangioendothelioma, as well as the majority of Kaposi sarcoma cases. Strong expression of B2-ARP was present in lymphangioleiomyomatosis, sinonasal hemangiopericytoma, retiform hemangioendothelioma, and in most Littoral cell angiomas and epithelioid hemangioendotheliomas. Strong expression of B3-AR was limited to most cases of epithelioid hemangioendothelioma and minority of cases of spindle cell hemangioma, angiosarcoma, Kaposi sarcoma and intimal sarcoma. Strong expression of B2-AR and its phosphorylated form B2-ARP were not necessarily congruent, but weak expression of the counterpart was usually present.
Conclusions: This is the first study to report B-adrenergic receptor expression in a variety of adult vascular lesions. While immunohistochemical expression of these receptors does not necessarily indicate that similar pathways of responsiveness to beta-blockade are present in these lesions, their presence does raise the possibility that beta-blockade could potentially effect apoptosis and decreased responsiveness to VEGF. Additional study is warranted as therapeutic options are limited for many patients with these tumors.
Category: Bone & Soft Tissue

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 24, Tuesday Morning

 

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