Different Metabolomic and Proteomic Profiles of Cerebrospinal Fluid in Ventricular and Lumbar Compartments in Relation to Leptomeningeal Metastases

The different molecular profiles of cerebrospinal fluid (CSF) between ventricular and lumbar compartments remain elusive, especially in the context of leptomeningeal metastasis (LM), which affects CSF flow. We evaluated CSF metabolomic and proteomic profiles based on the compartments and the diagnosis of spinal LM, proved by MRI from 20 paired ventricular and lumbar CSF samples of LM patients, including 12 spinal LM (+) samples. In metabolome analysis, 9512 low-mass ions (LMIs) were identified—7 LMIs were abundant in all lumbar versus paired ventricular CSF samples, and 3 LMIs were significantly abundant in all ventricular CSF. In comparisons between spinal LM (+) CSF and LM (−) CSF, 105 LMIs were discriminative for spinal LM (+) CSF. In proteome analysis, a total of 1536 proteins were measured. A total of 18 proteins, including complement C3, were more highly expressed in all lumbar CSF, compared with paired ventricular CSF, while 82 proteins, including coagulation factor V, were higher in the ventricular CSF. Of 37 discriminative proteins, including uteroglobin and complement component C8 gamma chain, 4 were higher in all spinal LM (+) CSF versus spinal LM (−) CSF. We further evaluated metabolic pathways associated with these discriminative proteins using the Gene Ontology database. We found that 16/17 spinal LM (+) pathways, including complement activation, were associated with lumbar discriminative proteins, whereas only 2 pathways were associated with ventricular-discriminative proteins. In conclusion, we determined that metabolite and protein profiles differed between paired lumbar and ventricular CSF samples. The protein profiles of spinal LM (+) CSF showed more similarity with the lumbar CSF than the ventricular CSF. Thus, we suggest that CSF LMIs and proteins could reflect LM disease activity and that LM-associated differences in CSF are more likely to be present in the lumbar compartment.

Experimental Assessment of Leptomeningeal Metastasis Diagnosis in Medulloblastoma Using Cerebrospinal Fluid Metabolomic Profiles

Diagnosing leptomeningeal metastasis (LM) in medulloblastoma is currently based on positive cerebrospinal fluid (CSF) cytology or magnetic resonance imaging (MRI) finding. However, the relevance of discordant results has not been established. We evaluated the diagnostic potential of CSF metabolomic profiles in the medulloblastoma LM assessment. A total of 83 CSF samples from medulloblastoma patients with documented MRI and CSF cytology results at the time of sampling for LM underwent low-mass ions (LMIs) analysis using liquid chromatography-mass spectrometry. Discriminating LMIs were selected by a summed sensitivity and specificity (>160%) and LMI discriminant equation (LOME) algorithms, evaluated by measuring diagnostic accuracy for verifying LM groups of different MRI/cytology results. Diagnostic accuracy of LM in medulloblastoma was 0.722 for cytology and 0.889 for MRI. Among 6572 LMIs identified in all sample, we identified 27 discriminative LMIs differentiating MRI (+)/cytology (+) from MRI (−)/cytology (−). Using LMI discriminant equation (LOME) analysis, we selected 9 LMIs with a sensitivity of 100% and a specificity of 93.6% for differentiating MRI (+)/cytology (+) from MRI (−)/cytology (−). Another LOME of 20 LMIs significantly differentiated sampling time relative to treatment (p = 0.007) and the presence or absence of LM-related symptoms (p = 0.03) in the MRI (+)/cytology (−) group. CSF metabolomics of medulloblastoma patients revealed significantly different profiles among LM diagnosed with different test results. We suggest that LM patients could be screened by appropriately selected LOME-generated LMIs to support LM diagnosis by either MRI or cytology alone.

Successful Remedy With Osimertinib in a Patient of Thr790Met-positive Non-small Cell Lung Cancer With Leptomeningeal Carcinomatosis and Resistant to Gefitinib

Patients of non-small cell lung cancer (NSCLC) with activated EGFR mutations is more apt to develop leptomeningeal metastasis (LM) than the other types of lung cancers [1]. Examination of circulating tumor DNA (ctDNA) in cell-free cerebrospinal fluid (CSF) has been shown to be useful in detecting the genomic mutations of tumors in central nervous system (CNS) and has also been used to monitor tumor progression and evaluate the response to treatments [2]. Osimertinib, a third-generation EGFR tyrosine kinase inhibitor, is considered to be a recent standardized treatment for EGFR Thr790Met-mutant NSCLC because of its good efficacy in both systemic and CNS metastasis [3].

Quantitative Cerebrospinal Fluid Circulating Tumor Cells are a Potential Biomarker of Response for Proton Craniospinal Irradiation for Leptomeningeal Metastasis

Background Leptomeningeal metastasis (LM) involves CSF seeding of tumor cells. Proton craniospinal irradiation (pCSI) is potentially effective for solid tumor LM. We evaluated whether circulating tumor cells (CTCs) in the CSF (CTCCSF), blood (CTCblood), and neuroimaging correlates with outcomes after pCSI for LM. Methods We describe a single-institution consecutive case series of 58 patients treated with pCSI for LM. Pre-pCSI CTCs, the change in CTC post-pCSI (ΔCTC), and MRIs were examined. Central nervous system progression free survival (CNS-PFS) and overall survival (OS) from pCSI were determined using Kaplan Meier analysis, Cox proportional-hazards regression, time-dependent ROC analysis, and joint modeling of time-varying effects and survival outcomes. Results The median CNS-PFS and OS were 6 months (IQR:4-9) and 8 months (IQR:5-13), respectively. Pre-pCSI CTCCSF<53/3mL was associated with improved CNS-PFS (12.0 vs 6.0 months, p<0.01). Parenchymal brain metastases (n=34, 59%) on pre-pCSI MRI showed worse OS (7.0 vs 13 months, p=0.01). Through joint modeling, CTCCSF was significantly prognostic of CNS-PFS (p<0.01) and OS (p<0.01). A ΔCTC-CSF≥37 cells/3mL, the median ΔCTC-CSF at nadir, showed improved CNS-PFS (8.0 vs 5.0 months, p=0.02) and further stratified patients into favorable and unfavorable subgroups (CNS-PFS 8.0 vs 4.0 months, p<0.01). No associations with CTCblood were found. Conclusion We found the best survival observed in patients with low pre-pCSI CTCCSF and intermediate outcomes for patients with high pre-pCSI CTCCSF but large ΔCTC-CSF. These results favor additional studies incorporating pCSI and CTCCSF measurement earlier in the LM treatment paradigm.

Leptomeningeal metastasis from melanoma emulating chronic subdural hematoma: a case report

Background Melanoma is a disease in which the patient doesn’t know about the primary lesion, and it has a propensity to metastases to any organ in the human body. Amongst melanoma, leptomeningeal metastasis has the least incidence. Case presentation In this case, we report a 56-year-old lady presenting with headache, recurrent vomiting and slurring of speech which on imaging was suggestive of chronic subdural hematoma which had led to surgical preparation but upon further examination, and radioimaging was found to be leptomeningeal metastasis from melanoma for which systemic therapy was started. Conclusions The concern is vigilance that is much needed in any case presenting in emergency. When the diagnosis is chronic subdural hematoma, it is followed by surgical treatment which is not done for leptomeningeal metastasis.

CSIG-25. BAI1/ADGRB1 REGULATES TGFβ1-INDUCED MESENCHYMAL SWITCH IN MEDULLOBLASTOMA

Medulloblastoma (MB) is the most common malignant brain tumor in children. MB tends to metastasize to the brain meninges and subarachnoid space and the spinal cord. Leptomeningeal metastasis is frequently found at initial diagnosis and leads to tumor relapse after standard treatment. Leptomeningeal metastasis remains a major challenge and is related with poor outcome. Acquiring a better knowledge of molecular defects underlying metastatic disease is essential for the development of effective therapies. Brain-specific Angiogenesis Inhibitor 1 (BAI1/ADGRB1) is a transmembrane receptor of the adhesion GPCR family widely expressed in normal brain, but its expression is lost in the majority of medulloblastoma through epigenetic silencing. We reported that BAI1 protects p53 from Mdm2-mediated degradation and regulate tumor growth in medulloblastoma (Zhu D. et al, Cancer Cell, 2018). However, it is unclear whether BAI1 loss is important for tumor invasion and the mesenchymal phenotype in MB. Microarray analysis of the published MB dataset revealed that low BAI1 mRNA expression correlates with poor outcome and with expression of many key mesenchymal genes, including Fibronectin1, SLUG, and TWIST1. Restoration of BAI1 expression in human MB cells suppresses mesenchymal gene expression in culture, and dramatically decreases brain tumor invasion. Mechanistically, we found that the N-terminal thrombospondin type 1 repeat (TSR#1) of BAI1 inhibits the maturation process of TGFβ1, a key growth factor involved in EMT. BAI1 is silenced epigenetically in MB cells by methylated CpG-binding protein MBD2, and its expression can be reactivated by KCC-07, a blood-brain barrier permeable MBD2 inhibitor. We found that restoration of BAI1 expression by KCC-07 treatment dramatically reduced tumor cell invasion of MB cells. These experiments demonstrate that epigenetic silencing of BAI1 is important for activation of the MB invasive phenotype through TGFβ1 pathway activation. Epigenetic targeting of this process by KCC-07 can reduce MB invasion.

DDRE-05. LONG-TERM OUTCOME OF INTRATHECAL CHEMOTHERAPY WITH PEMETREXED IN LEPTOMENINGEAL METASTASIS FROM NON-SMALL CELL LUNG CANCER WITH EGFR-MUTATION: A CASE REPORT

Leptomeningeal metastasis (LM) is fatal complication of non-small cell lung cancer (NSCLC) ,which has a poor prognosis and lacks effective treatments. Pemetrexed, a multitargeted antifolate agent, has demonstrated antitumor activity, a few studies have shown intrathecal pemetrexed (IP) controllable toxicities and potential promising efficacy for LM from NSCLC patients. We report a patient who diagnosed with LM from NSCLC harboring epidermal growth factor receptor (EGFR) mutation in exons 21 via typical neurological symptoms, magnetic resonance imaging (MRI) and positive cerebrospinal fluid (CSF) cytology. The curative effect of tyrosine kinase inhibitor (TKI) targeted drugs was maintained for a short time, the first-generation TKI icotinib was 4 months, and the third-generation osimertinib was 4 months. Then the patient received IP, and osimertinib continued. 30 mg of pemetrexed were implemented on day 1 every weeks for 8 weeks via lumbar puncture, then 50 mg of pemetrexed on day 1 every 4 week for 8 times. This treatment regimen resulted in the alleviation of the neurological symptoms, the CSF level of carcinoembryonic antigen also decresed without obvious side effects. At the time of this manuscript’s submission, she had maintained stable disease (SD) for more than 11 months. To our knowledge, this study provides the first clinical evidence that longterm intrathecal chemotherapy with pemetrexed providing a therapeutic approach against LM from NSCLC.