Differential expression of SKI oncogene protein in hemangiomas

Objective: The pathogenesis for benign tumorigenesis in hemangiomas is unknown. Oncogene proteins may be influential in this process. SKI proteins have been previously described in various malignancies. We investigated the differential expression of the SKI (sarcoma viral oncogene) protein in hemangiomas. Study Design: Prospective basic science study. Subjects and Methods: Paraffin-embedded hemangioma tissues were obtained from the senior author from 2005 to 2006. We created the first vascular tissue array composed of 12 hemangioma specimens at various stages of growth and anatomic location. Two cores were taken from each sample. Controls were also included. Immunohistochemical studies were performed using SKI, CD31, and Ki67. Results: All 12 hemangioma tissues overexpressed the SKI protein. The staining pattern was perinuclear within the endothelial cells. The intensity of staining was inversely proportional to the growth stage. The endothelial cells that were SKI-positive were involved in active cell division. Conclusion: SKI oncogene protein is differentially and specifically expressed in hemangioma tissues. SKI acts as a transcriptional co-repressor and inhibits the TGF-β pathway, thus leading to uncontrolled cellular proliferation and transformation. All vascular controls were negative for SKI staining. Clinical Significance of Study: The SKI oncogene protein is upregulated by hemangiomas and may play a role in hemangioma tumorigenesis.