OBJECTIVETo investigate the expression of Fas/FasL in infantile hemangiomas and discuss the role of Fas/FasL in the pathologic evolution of infantile hemangioma.

METHODThe EnVision immunohistochemical stain and RT-PCR technique was used to examine the expression of Fas/FasL protein and mRNA in the infantile hemangiomas.

RESULTS(1) In the early and middle proliferating stage, a number of infantile hemangioma cells expressed Fas. In the late proliferating stage, the number of positive cells increased obviously and the expression of Fas mRNA was reaching the strongest level. In the early regressing stage the Fas still existed in some cells and after that the expression decreased quickly. (2) Up to the middle proliferating stage, there were a few of FasL(+) cells foound. In the late proliferating stage, the number of FasL(+) cells increased significantly. From the early regressing stage, the number of FasL(+) cells decreased rapidly and disappeared.

CONCLUSIONThere may exist significant correlation between the expression of Fas/FasL and the development of the infantile hemangioma cells. The apoptosis of the infantile hemangioma cells mediated by Fas/ FasL may be the major reason of the spontaneous involution of infantile hemangioma.