Abstract
Juvenile angiofibroma (JA) is a rare, sex-specific, and highly vascularized nasal tumor that almost exclusively affects male adolescents, but its etiology has been controversial. The G protein-coupled hormone receptor LHCGR [luteinizing hormone (LH)/choriogonadotropin (hCG) receptor] represents a promising new candidate for elucidating the underlying mechanisms of sex specificity, pubertal manifestation, and JA progression. We used highly sensitive RNAscope technology, together with immunohistochemistry, to investigate the cellular expression, localization, and distribution of LHCGR in tissue samples from JA patients. Our results provide evidence for LHCGR expression in subsets of cells throughout JA tissue sections, with the majority of LHCGR+ cells located in close vicinity to blood vessels, rendering them susceptible to endocrine LH/hCG signaling, but LHCGR+ cells were also detected in fibrocollagenous stroma. A majority of LHCGR+ cells located near the vascular lumen co-expressed the neural crest stem cell marker CD271. These results are intriguing as both LH and hCG are produced in a time- and sex-dependent manner, and are known to be capable of inducing cell proliferation and angiogenesis. Our results give rise to a new model that suggests endocrine mechanisms involving LHCGR and its ligands, together with autocrine and paracrine signaling, in JA vascularization and cell proliferation.