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PROX1

MIM.601546 1q32.2-q32.3

Thursday 6 October 2005

Defintion : Kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) are rare tumors mainly occurring in early childhood.

Ectopic overexpression of human Prox1 gene, a lymphatic endothelial nuclear transcription factor, promoted an aggressive behavior in 2 murine models of KHE.

Overall, KHE and TA shared an identical endothelial immunophenotype: the neoplastic spindle cells were Prox1, podoplanin, LYVE-1, CD31, and CD34, whereas endothelial cells within glomeruloid foci were Prox1, podoplanin, LYVE-1, CD31, and CD34.

The lesional cells of all infantile hemangiomas and pyogenic granulomas were negative for Prox1 in the presence of positive internal control.

These findings provide immunophenotypic evidence to support a preexisting notion that KHE and TA are closely related, if not identical.

Prox1 is an immunohistochemical biomarker helpful in confirming the diagnosis of KHE/TA and in distinguishing it from infantile hemangioma and pyogenic granuloma.

References

- Expression of prox1, lymphatic endothelial nuclear transcription factor, in Kaposiform hemangioendothelioma and tufted angioma. Le Huu AR, Jokinen CH, Ruben BP, Mihm MC, Weiss SW, North PE, Dadras SS. Am J Surg Pathol. 2010 Nov;34(11):1563-73. PMID: 20975337

- Harvey NL, Srinivasan RS, Dillard ME, Johnson NC, Witte MH, Boyd K, Sleeman MW, Oliver G. Lymphatic vascular defects promoted by Prox1 haploinsufficiency cause adult-onset obesity. Nat Genet. 2005 Oct;37(10):1072-81. PMID: 16170315