The Molecular Feature of HOX Gene Family in the Intramedullary Spinal Tumors

STUDY DESIGN: The expression of HOXB13 and HOXA9 proteins was detected. OBJECTIVE: The purpose of this study was to investigate the molecular signature of spinal ependymoma (EPN) and astrocytoma, 2 most common types of intramedullary spinal tumor. SUMMARY OF BACKGROUND DATA: Intramedullary spinal tumor is unusual. It leads to high neurological morbidity and mortality without treatment. Till now, its molecular feature has been elucidated up to a little extent. METHODS: A total of 37 cases of spinal EPN, including 12 myxopapillary EPNs (MEPNs), 18 classic EPNs, and 7 anaplastic EPNs, and another 12 cases of astrocytoma were selected for this study. Immunohistochemical analysis of a large cohort of patients providing clinical tumor samples was performed to compare the expression of HOXB13 and HOXA9 not only between spinal EPN and astrocytoma but also among all 3 World Health Organization grades of spinal EPN. RESULTS: The results showed that HOXB13 and HOXA9 were selectively expressed in spinal EPN instead of astrocytoma. Furthermore, we found the strongest positive response of HOXB13 in MEPN whereas that of HOXA9 was ubiquitously detected in all subgroups of EPN. CONCLUSION: Both specificity and sensitivity of HOXB13 in MEPN indicated that HOXB13 might be a diagnostic marker to distinguish MEPN from other 2 types of EPN and a promising therapeutic target for MEPN. The strong immunoreactivity of HOXA9 in spinal EPN suggested an indispensable role in the progression of spinal EPN, and further research on its molecular function will provide new clues for the development of treatment options. LEVEL OF EVIDENCE: N /A.