205 Liquid Biopsy Biomarker for Differentiating Neurofibroma/Schwannoma From Other Solid Mass Mimics

Abstract

INTRODUCTION: Interleukin13 receptor alpha 2 (IL13Ra2) is a high-affinity receptor for the interleukin 13 (IL13) cytokine. With the exception of the testes, in normal conditions, IL13Ra2 demonstrates little normal cell expression. Prior work in our laboratory has demonstrated that IL13Ra2 is expressed on benign and malignant peripheral nerve sheath tumors in sporadic and syndromic cases. We have shown in in vitro and in murine MPST models that the receptor can be utilized to facilitate the treatment of malignant peripheral nerve sheath tumors. While mice have membrane-bound and soluble forms of IL13Ra2, humans lack the soluble form. We have previously shown the detection of IL13Ra2 exosomes in the cerebrospinal fluid and plasma of patients with glioblastoma. METHODS: IL13Ra2 levels were obtained from plasma and tumor specimens of 17 patients with diagnoses of Schwannoma/Neurofibroma (n = 13) and Lipoma/AVM (n = 4). Plasma and Tumor specimens were collected pre-operatively on the day of tumor resection. Plasma levels of IL13Ra2 were measured with ELISA. The tumor specimen was placed in NP40 buffer for extraction then levels were measured with ELISA. RESULTS: The plasma level of IL13Ra2 is significantly elevated in patients with schwannoma/neurofibroma compared to patients with lipomas/AVMs. Increased level of IL13Ra2 in tumors correlates with the increased levels of IL13Ra2 in the plasma. CONCLUSIONS: Plasma level of IL13Ra2 has the potential for diagnosis and may serve as a liquid biopsy biomarker to help differentiate solid tumors like neurofibroma/schwannoma from lipomas /arteriovenous malformations.