Synchronous pulmonary adenocarcinoma and primary leptomeningeal large B-cell lymphoma-Diagnostic challenge in cerebrospinal fluid: A brief report.

Lung cancer is one of the most common causes of cancer-related deaths worldwide. During or after the treatment of lung cancer, patients might develop another malignant neoplasm. To our knowledge, synchronous pulmonary adenocarcinoma and leptomeningeal large B-cell lymphoma have not been reported in the literature. Herein, we report the first case of synchronous pulmonary adenocarcinoma and primary leptomeningeal lymphoma, which is challenging in cytological diagnosis using cerebrospinal fluid (CSF). Knowledge of this rare situation by cytopathologists might avoid misdiagnosis or erroneous tumor classification during the cytological diagnosis of CSF in the future.

Analysis of intrapatient heterogeneity of circulating tumor cells at the single-cell level in the cerebrospinal fluid of a patient with metastatic gastric cancer.

BACKGROUND: The aims of this study were to detect circulating tumor cells (CTCs) at the single-cell level in cerebrospinal fluid (CSF) and to identify intrapatient heterogeneity of CTCs in a patient with gastric cancer (GC) with leptomeningeal metastasis (LM) using Di-Electro-Phoretic Array technology. MATERIALS AND METHODS: The CSF samples were drawn from a patient who was diagnosed with GC with LM. The CSF samples were centrifuged and stained with antibody cocktail to recognize 4',6-diamidino-2-phenylindole, cytokeratin, and epithelial cell adhesion molecule (EpCAM). Gene sequencing was also conducted to evaluate the status of the gene alteration profile of CSFCTCs as compared with those of the CSF non-CTCs and the primary tumor tissue. RESULTS: Among total 38 cells from the samples, 25 cells represented CK+ (EpCAM+), which boiled down to 0.53 CTCs in 1 mL of CSF. Each CTC was heterogeneous in terms of morphology and degree of marker expression. Some CTCs have a spindle-like shape, whereas others have a round shape. Based on molecular profiling between the 25 CK+ (EpCAM+) CTCs and 13 CK-/EpCAM- cells (i.e., the non-CTCs), CSFCTCs harbored mutations such as MDM2, TP53, KRAS, STK11, and ALK, whereas mutation of these genes was not observed in the CSF non-CTCs. Four genes of nine mutational genes totally observed in the CSFCTCs were also noted in the primary tumor tissue. CONCLUSIONS: We enriched CTCs through a single-cell sorting process in CSF samples of a GC patient with LM. We also demonstrated the intrapatient heterogeneity of the CTCs at the single-cell level.

Detection of Leptomeningeal Disease Using Cell-Free DNA From Cerebrospinal Fluid.

Importance: Leptomeningeal disease (LMD) is a devastating complication of cancer that is frequently underdiagnosed owing to the low sensitivity of cerebrospinal fluid (CSF) cytologic assessment, the current benchmark diagnostic method. Improving diagnostic sensitivity may lead to improved treatment decisions. Objective: To assess whether cell-free DNA (cfDNA) analysis of CSF may be used to diagnose LMD more accurately than cytologic analysis. Design, Setting, and Participants: This diagnostic study conducted in a neuro-oncology clinic at 2 large, tertiary medical centers assessed the use of genomic sequencing of CSF samples obtained from 30 patients with suspected or confirmed LMD from 2015 through 2018 to identify tumor-derived cfDNA. From the same CSF samples, cytologic analyses were conducted, and the results of the 2 tests were compared. This study consisted of 2 patient populations: 22 patients with cytologically confirmed LMD without parenchymal tumors abutting their CSF and 8 patients with parenchymal brain metastases with no evidence of LMD. Patients were considered positive for the presence of LMD if previous CSF cytologic analysis was positive for malignant cells. The analysis was conducted from 2015 to 2018. Main Outcomes and Measures: The primary outcome was the diagnostic accuracy of cfDNA analysis, defined as the number of tests that resulted in correct diagnoses out of the total number of tests assayed. Hypotheses were formed before data collection. Results: In total, 30 patients (23 women [77%]; median age, 51 years [range, 28-81 years]), primarily presenting with metastatic solid malignant neoplasms, participated in this study. For 48 follow-up samples from patients previously diagnosed via cytologic analysis as having LMD with no parenchymal tumor abutting CSF, cfDNA findings were accurate in the assessment of LMD in 45 samples (94%; 95% CI, 83%-99%), whereas cytologic analysis was accurate in 36 samples (75%; 95% CI, 60%-86%), a significant difference (P = .02). Of 43 LMD-positive samples, CSF cfDNA analysis was sensitive to LMD in 40 samples (93%; 95% CI, 81%-99%), and cytologic analysis was sensitive to LMD in 31 samples (72%; 95% CI, 56%-85%), a significant difference (P = .02). For 3 patients with parenchymal brain metastases abutting the CSF and no suspicion of LMD, cytologic findings were negative for LMD in all 3 patients, whereas cfDNA findings were positive in all 3 patients. Conclusions and Relevance: This diagnostic study found improved sensitivity and accuracy of cfDNA CSF testing vs cytologic assessment for diagnosing LMD with the exception of parenchymal tumors abutting CSF, suggesting improved ability to diagnosis LMD. Consideration of incorporating CSF cfDNA analysis into clinical care is warranted.

[Diagnostic Value of Locally Produced Tumor Markers and Blood Brain Barrier
Integrity in Lung Cancer Patients with Leptomeningeal Metastasis].

BACKGROUND: Tumor markers (TM) in cerebrospinal fluid (CSF) are useful for diagnosing leptomeningeal metastasis (LM). It has not been fully exploited the diagnostic possibilities of the CSF levels since the basic fact that the TM concentration of CSF depends strongly upon the serum levels as well as upon the condition of the blood brain barrier (BBB). To analyze the intrathecal TM synthesis and evaluate the integrity of BBB can be helpful for the definitive diagnosis of LM. Therefore, the aim of this study was to further explore the clinical value of intrathecal TM synthesis and BBB in the diagnosis for the lung cancer patients with LM. METHODS: Twenty-five lung cancer patients with LM and 57 patients with nonmalignant neurological diseases (NMNDs) admitted to Nanjing Drum Tower Hospital from December 2016 to March 2020 were included. We compared the integrity of BBB and intrathecal TM synthesis between two groups, analyzed the correlation of CSF TM between the detection and intrathecal synthesis, and evaluated serial CSF cytology, the integrity of BBB and intrathecal TM synthesis when intrathecal chemotherapy for one patient. RESULTS: Ninety-four percent LM patients showed the dysfunction of BBB, and all LM patients showed at least one intrathecal synthesized TM in CSF. In one patient, the CSF cytology was negative for the first time, but LM was eventually diagnosed based on the the intrathecal TM synthesis and positive CSF cytology of repeated lumbar puncture. In LM group, no correlation was observed between the detection and intrathecal synthesized TM in CSF. In the control group, only 3.5% (2/57) NMNDs patients had the dysfunction of BBB and no patients had intrathecal TM synthesis, both the differences of which were statistically significant (P<0.05). Finally, evaluating the CSF cytology, integrity of BBB and intrathecal TM synthesis can be used to assess the intracranial treatment effect. Moreover, intrathecal TM synthesis changes earlier than cytology. CONCLUSIONS: The evaluation of intrathecal TM synthesis and integrity of BBB are novel clinical diagnostic tools. In addition, serial measurement of intrathecal synthesized TM may play an important role in monitoring efficacy of lung cancer patients with LM, which is worthy of further promotion and clinical application.

Cerebrospinal fluid findings in patients with hematologic neoplasms and meningeal infiltration.

Neoplastic cell infiltration into the central nervous system (CNS) is a serious complication of hematological neoplasms. Cytomorphology (CM) and flow cytometry (FC) have been used to detect meningeal infiltration. The association between CSF findings with the results of CM and FC is still poorly understood. We retrospectively evaluated CSF findings in 72 patients with hematological neoplasm and meningeal infiltration detected either by CM or FC. We compared CSF cell count, total protein concentration, and lactate concentration according to the type of hematological neoplasm. We also compared these CSF findings according to the FC and CM results (FC + CM + , FC + CM-, and FC-CM +). The proportion of patients with positive FC was higher than with CM (FC - 91.7%; CM - 63.9%). Thirty-five (48.6%) patients with meningeal infiltration had normal CSF cell count, normal total protein concentration, and normal lactate concentration. The proportion of cases in which these CSF parameters were normal did not differ according to the type of hematological neoplasm. The positivity of CM was significantly higher in patients with > 3 cell/mm3 (P = 0.015) but the positivity of FC was not significantly different between patients with > 3 cell/mm3 or ≤ 3 cells/mm3. Patients with positive CM had more CSF cells (P = 0.0005) and higher lactate concentration (P = 0.0165) than patients with negative CM. The absence of CSF changes in cell count and total protein and lactate concentrations does not exclude the presence of meningeal infiltration. Although CM is considered the gold standard, the probability of positive CM is low in patients without CSF abnormalities in these parameters. Patients with hematological neoplasm with suspected meningeal infiltration should be investigated with both methods.

Primary leptomeningeal T-cell lymphoblastic lymphoma: a rare cause of chronic meningitis.

Primary leptomeningeal lymphomatosis is a rare disease with only a few hundred cases reported. We present a patient with a relatively short history of 25 days of headache followed by diplopia who was found to have primary leptomeningeal T-cell lymphoma without evidence of systemic lymphoma. The patient responded well to chemotherapy along with intrathecal medication and cranial irradiation and returned to a completely normal state of health. Not all chronic meningitis is due to infection or self-limiting inflammatory causes. It is important to consider lymphoma as a differential even in the absence of constitutional features such as loss of weight, appetite, night sweats, lymphadenopathy or hepatosplenomegaly. T-cell lymphoma with only Central Nervous system (CNS) involvement is a rare cause of chronic meningitis, which is eminently amenable to treatment and is fatal if missed.

Intra-CSF topotecan in treatment of breast cancer patients with leptomeningeal metastases.

BACKGROUND: There are few treatment options for patients with leptomeningeal metastases (LM). METHODS: We report a case series of patients with breast cancer and LM treated with intra-CSF topotecan (TOPO). Outcome was assessed by clinical exam and MRI at baseline, at end of induction (4-5 weeks), then every 3 months; CSF cytology was determined at baseline and with each treatment. RESULTS: Thirty-one women [median age, 58 (37-81); median KPS 60 (40-100)] received treatment. At baseline, 68% had positive CSF cytology, and 90%, leptomeningeal enhancement on MRI. 84% of patients also received focal RT (not during TOPO) and 77% received concomitant systemic hormonal or chemotherapy. Median number of TOPO treatments was 14.5 (range, 3-71); median duration of treatment, 11 weeks (1-176); and median OS, 6.9 months (range, 0.9-48.8). Patients remaining progression-free during 4-6 weeks of induction (81%) had a median OS of 11.5 months (range, 1.8-48.8). Overall neurologic PFS at 6, 12, and 24 months was 39%, 26%, and 6%, respectively. Clearing of CSF malignant cells for >3 consecutive samples occurred in 10/21 (48%) patients with positive CSF cytology at baseline, remaining clear for a median duration of 15.9 months (range, 1.4-34.5). Grade 3 adverse events included headache or vomiting (3pts), T2 hyperintensity surrounding the ventricular catheter (2 pts), and meningitis (2 pts). CONCLUSIONS: Intra-CSF TOPO, with focal RT as needed for symptomatic areas of enhancement produced durable clearing of CSF malignant cells in 48% of patients positive at baseline, with promising median PFS and OS.

[Different Gene Mutation Spectrum of the Paired CSF and Plasma Samples in Lung Adenocarcinoma with Leptomeningeal Metastases: the Liquid Biopsy Based on Circulating Tumor DNA].

BACKGROUND: Leptomeningeal metastasis (LM) are a severe complication of non-small cell lung cancer (NSCLC), and normally accompanied by poor prognosis. For the patients with targetable mutations, epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are the preferred treatment, but the acquired TKI resistance is inextricable. The aim of this study is to analyze the different gene mutation spectrum and mutation frequency of the cerebrospinal fluid (CSF) and plasma in NSCLC patients with LM, and screen out the drug-resistant mutations so as to guide the choice of treatment accurately. METHODS: The paired CSF and plasma samples were collected from the NSCLC-LM patients with acquired TKI resistance. Next generation sequencing (NGS) was used to detect the gene variations of circulating tumor DNA (ctDNA). RESULTS: A total of 18 NSCLC patients with LM were collected. Of the basic mutations, 11 cases (61.11%) were EGFR, 6 cases (33.33%) were anaplastic lymphoma kinase (ALK), and 1 case (5.56%) was ROS proto-oncogene 1, receptor tyrosine kinase (ROS1). Tumor protein p53 gene (TP53) and mesenchymal-epithelial transition factor (MET) were the two most frequently accompanying mutated genes in CSF ctDNA. The detected mutation rate of CSF samples was higher than that of plasma samples (100.00% vs 66.67%, P=0.006), and the maximum allelic fractions were all higher in CSF than in plasma (P<0.001). Abundant single-nucleotide variations (SNV) and copy number variants (CNV) were detected in CSF, the amount of both of which were more than in blood. In addition, the CSF and plasma samples of patients treated with several TKIs had more SNV mutations than patients who received only a single TKI treatment. CONCLUSIONS: For the patients of NSCLC, ctDNA in CSF could reveal genomic alterations of LM more exactly and overally than it in plasma, thus could be an optimal source of liquid biopsy for guiding therapy, monitoring therapeutic effect, and predicting prognosis.

[A case of meningeal melanomatosis diagnosed by immunostaining of cerebrospinal fluid].

A 49-year-old woman was admitted to our hospital with suspected hypertensive encephalopathy. On the basis of MRI showing leptomeningeal enhancement and Class V cytology of the CSF, she was diagnosed as having leptomeningeal carcinomatosis. Although no primary site was detected, a few melanin granules were observed at the third CSF examination. The atypical cells in the CSF demonstrated immunoreactivity for HMB-45 and S-100, which are specific markers of malignant melanoma. There have been few reports of meningeal melanomatosis in Japan. This case illustrates that immunostaining is diagnostically useful in patients with leptomeningeal carcinomatosis from neoplasms with unknown primary sites.

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

BACKGROUND: This study profiled the somatic genes 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 bioinformatically analyzed by (Database for Annotation, Visualization and Integrated Discovery) DAVID software. RESULTS: The most common mutated gene was TP53 (54/62; 87.10%), followed by 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 were enriched in the PI3K-Akt signaling pathway by the KEGG pathway analysis. Furthermore, the CNVs of these genes were also identified in these 62 samples. The mutated genes in CSF samples receiving intrathecal chemotherapy and systemic therapy were enriched in the ERK1/2 signaling pathway. CONCLUSIONS: This study identified genes 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.

Leptomeningeal involvement by relapsed follicular lymphoma detected by flow cytometry despite exceedingly low white blood cell counts in cerebrospinal fluid: A case report.

Follicular lymphoma is usually an indolent non-Hodgkin lymphoma that rarely involves the central nervous system (CNS) and flow cytometric detection of such lymphoma in cerebrospinal fluid (CSF) is often challenging because of low cellularity and viability of CSF samples. Here, we report our experience in a 52-year-old man whose relapsed follicular lymphoma with leptomeningeal involvement was confirmed by flow cytometric analysis of CSF, despite an exceedingly low white blood cell count (3/cumm).

Leptomeningeal malignancy of childhood: sharing learning between childhood leukaemia and brain tumour trials.

Leptomeningeal malignancy complicates childhood cancers, including leukaemias, brain tumours, and solid tumours. In leukaemia, such malignancy is thought to invade leptomeninges via the vascular route. In brain tumours, dissemination from the primary tumour, before or after surgery, via CSF pathways is assumed; however, evidence exists to support the vascular route of dissemination. Success in treating leptomeningeal malignancy represents a rate-limiting step to cure, which has been successfully overcome in leukaemia with intensified systemic therapy combined with intra-CSF therapy, which replaced cranial radiotherapy for many patients. This de-escalated CNS-directed therapy is still associated with some neurotoxicity. The balanced benefit justifies exploration of ways to further de-escalate CNS-directed therapy. For primary brain tumours, standard therapy is craniospinal radiotherapy, but attendant risk of acute and delayed brain injury and endocrine deficiencies compounds post-radiation impairment of spinal growth. Alternative ways of treating leptomeninges by intensifying drug therapy delivered to CSF are being investigated-preliminary evidence suggests improved outcomes. This Review seeks to describe methods of intra-CSF drug delivery and drugs in use, and consider how the technique could be modified and additional drugs might be selected for this route of administration.

Simultaneous primary cancer occurrence of melanoma and pulmonary adenocarcinoma in leptomeningeal metastases: a case report.

BACKGROUND: Leptomeningeal metastasis (LM) is a predominantly late stage, devastating complication of a variety of malignant solid tumors. Diagnosis relies predominantly on neurological, radiographic, and cerebrospinal fluid (CSF) assessments. Recently, liquid biopsy tests derived from CSF has shown to be a feasible, noninvasive promising approach to tumor molecular profiling for proper brain cancer diagnostic treatment, thereby providing an opportunity for CSF-based personalized medicine. However, LM is typically misleadingly assumed to originate from only one primary tumor type. CASE PRESENTATION: In this case report, we provide first evidence of the co-occurrence of LM originating from more than one primary tumor types. DISCUSSION AND CONCLUSIONS: Based on this patient case profile, the co-occurrence of LM from two or more primary tumor types should be accounted for when deriving diagnostic conclusions from liquid biopsy tests.

New Frontiers in Diagnosis and Therapy of Circulating Tumor Markers in Cerebrospinal Fluid In Vitro and In Vivo.

One of the greatest challenges in neuro-oncology is diagnosis and therapy (theranostics) of leptomeningeal metastasis (LM), brain metastasis (BM) and brain tumors (BT), which are associated with poor prognosis in patients. Retrospective analyses suggest that cerebrospinal fluid (CSF) is one of the promising diagnostic targets because CSF passes through central nervous system, harvests tumor-related markers from brain tissue and, then, delivers them into peripheral parts of the human body where CSF can be sampled using minimally invasive and routine clinical procedure. However, limited sensitivity of the established clinical diagnostic cytology in vitro and MRI in vivo together with minimal therapeutic options do not provide patient care at early, potentially treatable, stages of LM, BM and BT. Novel technologies are in demand. This review outlines the advantages, limitations and clinical utility of emerging liquid biopsy in vitro and photoacoustic flow cytometry (PAFC) in vivo for assessment of CSF markers including circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), microRNA (miRNA), proteins, exosomes and emboli. The integration of in vitro and in vivo methods, PAFC-guided theranostics of single CTCs and targeted drug delivery are discussed as future perspectives.

The RANO Leptomeningeal Metastasis Group proposal to assess response to treatment: lack of feasibility and clinical utility and a revised proposal.

BACKGROUND: A scorecard to evaluate magnetic resonance imaging (MRI) findings during the course of leptomeningeal metastases (LM) has been proposed by the Response Assessment in Neuro-Oncology (RANO) group. METHODS: To explore the feasibility of the Leptomeningeal Assessment in Neuro-Oncology (LANO) scorecard, cerebrospinal MRIs of 22 patients with LM from solid tumors were scored by 10 neuro-oncologists and 9 neuroradiologists at baseline and at follow-up after treatment. Raters were blinded for clinical data including treatment. Agreement between raters of single items was evaluated using a Krippendorff alpha coefficient. Agreement between numerical parameters such as scores for changes between baseline and follow-up and total scores was evaluated by determining the intraclass coefficient of correlation. RESULTS: Most raters experienced problems with the instructions of the scorecard. No acceptable alpha concordance coefficient was obtained for the rating of single items at baseline or follow-up. The most concordant ratings were obtained for spinal nodules. The concordances were worst for brain linear leptomeningeal enhancement and cranial nerve enhancement. Discordance was less prominent among neuroradiologists than among neuro-oncologists. High variability was also observed for evaluating changes between baseline and follow-up and for total scores. CONCLUSIONS: Assessing response of LM by MRI remains challenging. Central imaging review is therefore indispensable for clinical trials. Based on the present results, we propose a new, simplified scorecard that will require validation using a similar approach as pursued here. The main challenges are to define measurable versus nonmeasurable (target) lesions and measures of change that allow assessment of response.

Osimertinib Quantitative and Gene Variation Analyses in Cerebrospinal Fluid and Plasma of a Non-small Cell Lung Cancer Patient with Leptomeningeal Metastases.

BACKGROUND: Leptomeningeal metastases (LM) are much more frequent in patients of non-small lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. Osimertinib, a third-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFRTKI) shows promising efficacy for LM. OBJECTIVE: The aim of this study was to analyze the concentration of osimertinib and gene variation of circulating tumor DNA (ctDNA) in human plasma and cerebrospinal fluid (CSF). Furthermore, we explored whether ctDNA in CSF might be used as a biomarker to predict and monitor therapeutic responses. METHODS: The dynamic paired CSF and blood samples were collected from the NSCLC patient with LM acquired EGFR-TKI resistance. A method based on ultra-high performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) was developed and validated for detecting osimertinib in CSF and plasma samples. Gene variations of ctDNA were tested by next-generation sequencing with a panel of 1021 genes. RESULTS: The concentrations of osimertinib in CSF were significantly lower than that in plasma (penetration rate was 1.47%). Mutations included mTOR, EGFR, CHECK1, ABCC11, and TP53 were explored in ctDNA from plasma and CSF samples. The detected mutation rate of CSF samples was higher than that of plasma samples (50% vs. 25%). Our data further revealed that the variations allele frequency (VAF) and molecular tumor burden index (mTBI) of ctDNA derived from CSF exhibited the negative correlation with efficacy of treatment. CONCLUSION: ctDNA from CSF might be a useful biomarker for monitoring the efficacy of treatment and an effective complement to nuclear magnetic resonance imaging (MRI) for LM.

Unique genomic profiles obtained from cerebrospinal fluid cell-free DNA of non-small cell lung cancer patients with leptomeningeal metastases.

BACKGROUND: Leptomeningeal metastases (LM), associated with poor prognosis, are frequent complications of advanced non-small cell lung cancer (NSCLC) patients, especially in patients with epidermal growth factor receptor (EGFR) mutations. Due to limited access to leptomeningeal lesions, the mutational landscape of LM has not been comprehensively investigated in large cohorts and the underlining biology of LM remains elusive. Some studies have explored the potential of cerebrospinal fluid (CSF) in reflecting the molecular profile of LM but with limited number of patients enrolled. METHODS: In this study, we performed capture-based targeted sequencing using a panel consisting of 168 lung cancer-related genes on matched CSF and plasma samples from 72 advanced NSCLC patients with confirmed LM to interrogate the potential of CSF as a source of liquid biopsy. RESULTS: We revealed a rate of detection of 81.5% and 62.5% for CSF and plasma, respectively (p = 0.008). The maximum allelic fraction (MaxAF) was also significantly higher in CSF (43.6% vs. 4.6%) (p < 0.001). CSF, harboring a unique genomic profile by having a significant number of CSF-specific mutations, primarily copy number variations, is superior to plasma in reflecting the mutational profile of LM. Further pathway enrichment analysis revealed that most of CSF-specific mutations participated in pathways relevant to the tumorigenesis and the development of metastases. Moreover, our data also revealed that TP53 loss of heterozygosity (LOH) predominantly existed in CSF (p < 0.001). CONCLUSIONS: Collectively, we demonstrated that CSF provides a more comprehensive profile of LM than plasma in a large cohort, thus can be used as an alternative source of liquid biopsy for LM patients.