A Common Polymorphism within the IGF2 Imprinting Control Region Is Associated with Parent of Origin Specific Effects in Infantile Hemangiomas

Infantile hemangioma (IH) is the most common tumor of the pediatric age group, affecting up to 4% of newborns ranging from inconsequential blemishes, to highly aggressive tumors. Following well defined growth phases (proliferative, plateau involutional) IH usually regress into a fibro-fatty residuum. Despite the high prevalence of IH, little is known regarding the pathogenesis of disease. A reported six fold decrease in IGF2 expression (correlating with transformation of proliferative to involuted lesions) prompted us to study the IGF-2 axis further. We demonstrate that IGF2 expression in IH is strongly related to the expression of a cancer testes and suspected oncogene BORIS (paralog of CTCF), placing IH in the unique category of being the first known benign BORIS positive tumor. IGF2 expression was strongly and positively related to BORIS transcript expression. Furthermore, a stronger association was made when comparing BORIS levels against the expression of CTCF via either a percentage or difference between the two. A common C/T polymorphism at CTCF BS6 appeared to modify the correlation between CTCF/BORIS and IGF2 expression in a parent of origin specific manner. Moreover, these effects may have phenotypic consequences as tumor growth also correlates with the genotype at CTCF BS6. This may provide a framework for explaining the clinical variability seen in IH and suggests new insights regarding CTCF and BORIS related functionality in both normal and malignant states.