Characterization of candidate tissue and blood biomarkers in a rare cohort of myxopapillary ependymoma patients.

2040 Background: Myxopapillary ependymoma (MPE) is a very rare tumor of the distal spinal cord. Despite benign histopathology, local recurrences occur in approximately 30% of patients and distant metastases have been described in few cases. We investigated candidate tissue and blood biomarkers in a rare MPE series. Methods: Formalin fixed paraffin embedded (FFPE) tumour tissues from 21 MPE patients were immunohistochemically investigated for expression of isocitrate dehydrogenase 1 R132H (IDH-R132H), Secretagogin, glial fibrillary acidic protein (GFAP), epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), progesterone receptor (PR), estrogen receptor (ER), Ki-67, arg, plateled derived growth factor a (PDGFRa) and b (PDGFRb), pc-kit and pc-abl. EGFR gene was evaluated using exon-sequencing. In addition, we analyzed circulating plasma-GFAP using ELISA in 3 patients with completely resected MPE, 1 patient with locally advanced MPE, 2 patients with pleuropulmonary metastas...