Detection of genes mutations in cerebrospinal fluid circulating tumor DNA from neoplastic meningitis patients using next generation sequencing

Abstract

Background: This study profiled the somatic gene mutations and the copy number variations (CNVs) in cerebrospinal fluid (CSF)-circulating tumor DNA (ctDNA) from patients with neoplastic meningitis (NM). Methods: A total of 62 CSF ctDNA samples were collected from 58 NM patients for the next generation sequencing. The data were blasted in GenBank and bioinformatically analyzed. Results: Cancer-associated gene mutations occurred in all 62 CSF ctDNA samples in TP53 (54/62; 87.10%), EGFR (44/62; 70.97%), PTEN (39/62; 62.90%), CDKN2A (32/62; 51.61%), APC (27/62: 43.55%), TET2 (27/62; 43.55%), GNAQ (18/62; 29.03%), NOTCH1 (17/62; 27.42%), VHL (17/62; 27.42%), FLT3 (16/62; 25.81%), PTCH1 (15/62; 24.19%), BRCA2 (13/62; 20.97%), KDR (10/62; 16.13%), KIT (9/62; 14.52%), MLH1 (9/62; 14.52%), ATM (8/62; 12.90%), CBL (8/62; 12.90%), and DNMT3A (7/62; 11.29%). The mutated genes enriched by the KEGG pathway analysis were the PI3K-Akt, which included the genes of TP53, EGFR, PTEN, KIT and KDR. After receiving intrathecal and systemic chemotherapy, the ERK1/2 signaling pathways of these CSF samples were activated. Furthermore, the CNVs of these genes were also identified in these 62 samples. Conclusions: This study identified gene mutations in all CSF ctDNA samples, indicating that these mutated genes may be acted as a kind of biomarker for diagnosis of NM, and these mutated genes may affect meningeal metastasis through PI3K-Akt signaling pathway.