PATH-50. HIGH DETECTION RATE OF MYD88MUTATIONS IN CEREBROSPINAL FLUID FROM PATIENTS WITH CENTRAL NERVOUS SYSTEM LYMPHOMAS. (5th November 2018)

• Record Type: Journal Article
• Authors: Watanabe, Jun; Natsumeda, Manabu; Okada, Masayasu; Kobayashi, Taiki; Kanemaru, Yu; Oishi, Makoto; Kakita, Akiyoshi; Fujii, Yukihiko
• Is Part Of: Neuro-oncology. Volume 20(2018)Supplement 6
• Page Start: vi169
• Page End: vi169
• Publication Date: 2018-11-05
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noy148.704
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: OBJECT: Biopsy is generally necessary for the diagnosis of primary central nervous system lymphoma PCNSL. However, surgical biopsy has problems of fatal hemorrhagic complication and false negative findings, so more safe and reliable diagnostic methods are required. The aim of this present study is to detect MYD88 mutations, an important driver mutation, in cerebrospinal fluid (CSF) taken from PCNSL patients. METHOD: Fifteen CNS lymphoma (13 PCNSL, 3 CNS relapse from systemic lymphoma) patients were studied. We obtained cell free DNA (cfDNA) from CSF by lumbar puncture. CfDNA was extracted from 1ml of CSF, and both direct sequence and droplet digital PCR (ddPCR) were performed. Furthermore, we performed direct sequence from surgical obtained formalin fixed paraffin embedded (FFPE) tissue and analyzed the relationship to clinical data. RESULT: The mean cfDNA concentration of 1 ml CSF was 188.8 ng/ml [95% CI 124.2–253.8 ng/ml]. MYD88 mutations from CSF were detected in 60.0% (9 of 15 cases), and L265P in exon5 was the most frequent mutation in 8 out of 9 (88.8%) cases, S219C in exon3 was detected in one case. In 2 patients, MYD88 mutation was confirmed by ddPCR but not direct sequence. In all 8 cases with sufficient FFPE tissue for DNA analysis, MYD88 mutation was confirmed in the FFPE tissue. In 1 patient, there was insufficient FFPE tissue for DNA analysis. MYD88 mutation was not detected in the CSF of all 6 patients without MYD88 mutation in the tumor. CONCLUSION: This pilot study provided evidence that the somatic driver mutation MYD88 can be reliably detected by direct sequence and ddPCR in the cfDNA taken from 1 ml of CSF in patients with CNS lymphomas.