APLN/APJ may act as a Novel Diagnostic Marker and a Potential Therapeutic Target for Infantile Hemangioma

Abstract Background: Infantile hemangioma (IH) is the most common benign tumor in children with the characteristics of endothelial cells (ECs) proliferation and natural regression, and recent evidence shows that abnormal proliferation of ECs of IH is closely related to Apelin and Apelin receptor (APLN/APJ). This study aimed to evaluate and compare the immunoexpression of APLN/APJ and angiogenic index about IH, and establish the specificity with the histomorphology. Methods: 3 IHs（proliferating）, 3 IHs（involuting）, 3 congenital hemangiomas (CHs), 3 pyogenic granulomas (PGs), 3 capillary malformations (CMs), and 3 venous malformations (VMs) were submitted to morphological and immunohistochemical analysis. APLN/APJ expression was semi-quantitatively evaluated, and the angiogenic index was assessed by microvessel counts (MVC). Results: Higher APLN/APJ immunoexpression was observed in the proliferating phase of IHs compared to the involuting phase of IHs (p ＜ 0.05). Compared with CD31, APJ/APLN only expressed in proliferating and partial involuting phases of IHs; Compared with GLUT-1, APLN/APJ was expressed specifically in IH vascular ECs. APLN/APJ expression and angiogenic index significantly correlated in the IHs study. Conclusions: our research suggests that the expression of APLN/APJ in IH is specific, and may reflect the influence on the initiation and regulation of IH, which can be used as a new specific antibody for clinical pathological diagnosis and a new target for clinical treatment.