Introduction: Ependymomas are the third most common solid brain tumor in pediatric patients. Their prognosis is largely dependent on their ability to be surgically resected. Tumor resection may be more feasible if it is discovered earlier, prior to extensive growth. This makes the identification of markers of ependymoma tumor growth potentially advantageous for their treatment.
Methods: The authors searched the CCMC neuro-oncology sera-bank for samples from patients with confirmed intracranial ependymomas. 3 patients were identified from 2015 – 2016. Within the same time frame, 5 patients with no radiographic evidence of tumor, were identified within the bank’s controls.
Samples were thawed and centrifuged, then the liquid phase was extracted. The sera supernatant was processed via a QiaCube. mirRNA was extracted using miRNEasy and an miScript Pre-Amp (Qiagen, Germany).
Samples were run on pre-fabricated 96-well RT-PCR array plates probed with 84 miRNA primers relevant to human brain tumors (Qiagen, Germany).
Results: No significant changes were noted in the serum circulating miRNA profile of patient’s with ependymoma versus control patients. There was an overall trend towards miRNA suppression in the ependymoma patients.
Compared to a benign tumor patient (DNET) and a malignant tumor patient (GBM), ependymoma sera mir-328 levels trended towards lower levels (Fold ? -1.15 vs DNET and -15,058.94 vs GBM). Mir-21, likewise, trended towards downregulation in ependymoma versus the benign tumor sample (Fold ? -182,179.36).
Conclusions: Serum miRNA profiles of pediatric ependymoma patients and controls are indistinguishable.
Unlike sera from patients with WHO grade I and grade IV tumors, ependymoma patients show trends in overall suppression of circulating miRNA, particularly mir-21 and mir-328, a pro-invasion miRNA. This is consistent with the lack of parenchymal invasion in ependymomas.
A larger patient cohort would be needed to confirm these miRNA trends.
Patient Care: Detection remains a problem for many pediatric tumor patients, as the symptoms are often subtle prior to the tumor reaching a large size. This research hopes to better identify changes in peripheral miRNA due to ependymoma growth, so that the information may some day lead to better tumor detection.
Learning Objectives: By the conclusion of this session, partipants whould be able to:
1) Identify the varriances in sera miRNA levels peculiar to pediatric ependymoma patients.
2) Describe the differences between ependymoma and DNET and GBM sera miRNA levels.