Analysis of Follicle-Stimulating Hormone Receptor in Infantile Hemangioma.

INTRODUCTION: The life cycle of infantile hemangioma (IH) and secretion of follicle-stimulating hormone (FSH) are identical. We previously have shown that IH contains the FSH receptor (FSHR). The purpose of this study was to identify which cell type(s) in IH expresses FSHR.

METHODS: Human proliferating IH tissues obtained during a clinically indicated surgical procedure were used. Paraffin sections and isolated cell populations (endothelial, pericyte, stem cell) were subjected to immunofluorescence for FSHR. Tissues were costained with DAPI, anti-α smooth muscle actin, or biotinylated Ulex Europaeus Agglutinin I to identify nuclei, pericytes, and endothelial cells, respectively. Whole tissue and purified single cell populations underwent polymerase chain reaction (PCR) for FSHR. Positive control specimens (ovary, sertoli cells) and negative control tissues (skin/subcutis, hepatic cells) were included.

RESULTS: Immunofluorescence of 9 IHs demonstrated that FSHR was enriched in pericytes compared with endothelial cells. Follicle-stimulating hormone receptor was expressed in 6 of 6 whole tissue IHs along with the positive control via PCR. Follicle-stimulating hormone receptor was not present in the negative control samples. Four of 5 sets of pericytes expressed FSHR by PCR. Neither IH endothelial cells, IH stem cells, nor negative control cells exhibited FSHR by PCR.

CONCLUSIONS: Because the secretion of FSH correlates with the growth pattern of IH, FSH might be involved in the disease process. Follicle-stimulating hormone receptor is enriched in the pericytes of IH, suggesting that this cell type may be involved in the pathogenesis of the tumor.