Table 1. Tabulated analysis of the selected studies.

CSF: cerebrospinal fluid; EVD: extraventricular drainage; APOE: apolipoprotein E; PTGDS: prostaglandin D2 synthase; miRNA: micro RNA; PCR: polymerase chain reaction; GAL: galanin; HSPA5: heat shock 70 kDa protein 5; WNT4: wingless-type MMTV integration site family, member 4; CNS: central nervous system; MMD: moyamoya disease

Author/Year	Purpose	Type of study	Subjects	Results	Outcomes
Bruschi et al. (2021) [27]	To understand the potential biomarkers of childhood brain tumor identified by proteomics of CSF from EVD	Systematic review	CSF from EVD from 29 children bearing different brain tumors and 17 controls needing EVD insertion for unrelated causes	1,598 and 1,526 proteins were identified by liquid chromatography-coupled tandem mass spectrometry proteomics in CSF control and brain tumor patients, respectively; 263 and 191 proteins were exclusive of either condition	The method was able to differentiate between brain tumor vs. non-tumor/hemorrhagic conditions (controls) and to differentiate between two large classes of brain tumors
Ghantasala et al. (2021) [8]	To study the importance of targeted proteomics in the detection and validation of proteins with roles in pathobiology of brain tumors	Randomized controlled trial	17 CSF Samples	In the CSF samples of patients with meningioma, the peptides of APOE proteins resulted in a cumulative fold change of 2.21 while the peptides of PTGDS proteins resulted in a fold change of 1.52	A study of the CSF proteins could be used in place of surgery in the diagnosis of meningioma
Slavik et al. (2020) [21]	To indefinity meningioma patients at high risk of tumor recurrence using miRNA profiling	Cohort study	In a cohort of 172 patients, deregulated miRNA was further confirmed using quantitative real-time polymerase chain reaction	The most important prognosticators were miR-15a-5p, miR-146a-5p, and miR-331-3p, according to the adjusted and non-adjusted models of time to relapse. miRNAs were still prognosticators in meningiomas	The presented models may allow for more accurate prediction of time to recurrence of meningioma
Xiao et al. (2020) [9]	To describe and properly discuss the clinical roles of distinct classes of CSF biomarkers, isolated from patients with brain tumors	Systematic review	Various studies on the role of CSF in brain tumors	CSF proteins such as miRNAs and circulating tumor DNA among others can be used to detect and assess the progression of brain tumors as a form of liquid biopsy	The protein biomarkers in the CSF can be essential in not only the diagnosis but also the treating procedures, as well as in assessing recurring tumors, and thus aid the oncologists and other physicians clinically
Kopkova et al. (2019) [19]	CSF miRNA signatures as diagnostic biomarkers in brain tumors	Prospective monocentric study	175 patients with brain tumor and 40 patients without tumors but have hydrocephalous as a control experiment	5 miRNA levels were successfully identified and upon CSF diagnostic scores for various brain tumors, and the specific tumors were defined and differentiated from healthy samples	This was the largest research on miRNA and brain tumor diagnosis and it concluded that the protein biomarker can be useful not only in the diagnosis but also the prognosis of brain tumors
Kopkova et al. (2018) [14]	To highlight the potential of CSF miRNAs as diagnostic, prognostic. and predictive biomarkers in brain tumors and to summarize technological approaches for detection of CSF miRNAs	Systematic review	Multiple CSF samples taken of patients with various neurological disorders including brain tumors	MiRNAs are often components of circulating fluids including CSF and have been found to be prospective diagnostic biomarkers for patients with brain tumors including meningioma	The effectiveness of treatment for brain tumor patients depends on the early detection of the tumor, and it is therefore important that various biomarkers that can lead to this be identified and implemented. This includes miRNAs which have been under research and require more exploration to optimize their use as biomarkers
Shalaby et al. (2016) [10]	To discuss the potential and limitations of CSF analyses in brain cancer patients	Systematic review	Various types of CSF analysis employed in the diagnosis of brain tumors	The various CSF components such as various proteins and miRNA show potential in the field of oncology but there is still a long way to go to bring this to the clinical setting	CSF could provide critical biomarkers for use in the oncology field, especially in the diagnosis of CNS conditions. However, for the benefits of this technology, it is essential research and collaboration between researchers and clinical practitioners
Ludwig et al. (2015) [20]	To discuss post-transcriptional deregulation of signaling pathways in meningioma subtypes by differential expression of miRNAs	Systematic review	Compared the expression of 1,205 miRNAs in different meningioma grades and histological subtypes using microarrays and independently validated deregulation of selected miRNAs with quantitative real-time PCR	Identified 13 miRNAs deregulated between different subtypes of benign meningiomas, and 52 miRNAs deregulated in anaplastic meningioma compared with benign meningiomas	MiRNAs contributes to the clinical spectrum of benign meningiomas
Shen et al. (2014) [11]	To review the current available knowledge on the use of CSF proteome analysis as diagnostic biomarkers for brain tumors	Systematic review	Current published research on the use of CSF proteome analysis in the diagnosis of brain tumors	Various proteins such as GAL, HSPA5, and WNT4 were observed to be in lower quantity in patients with brain tumors	The various proteins identified in the study could bring about clinical breakthrough in the diagnosis of various forms of brain tumors
Anagnostopoulos and Tsangaris (2014) [12]	To summarize the current knowledge on research applying proteomics techniques or proteomic-based approaches performed on pediatric brain tumors	Systematic review	Currently available knowledge on research that applied proteome analysis methods in the diagnosis of brain tumors	Various proteins such as calcyphosin among others that can be potential biomarkers in the diagnosis of brain tumors were identified and discussed	Proteomics provide hope for a better future in the field of oncology in the diagnosis of brain tumors
Samuel et al. (2014) [13]	To analyze the existing literature on proteomics in oncology of the neural systems and their contribution to the clinical practice	Systematic review	All current available literature on proteome analysis in oncology	There are various biomarkers that can be used in the diagnosis of various brain tumors as well as other conditions of the CNS, and these biomarkers can be obtained from CSF analysis	The analysis of CSF for biomarkers could provide diagnostic tools for various brain tumors and conditions at the clinical level and help move away from the current invasive methods such as biopsies
Kim et al. (2012) [6]	To identify meningioma-specific CSF proteins from 4 patients with a meningioma and 4 patients with a non-brain tumorous lesion	Randomized controlled trial	Four patients with meningioma and 4 patients with a non-brain tumorous lesion	The proteins APOE, apolipoprotein J and alpha-1-proteinase inhibitor were increased while the proteins PTGDS, transthyretin, and β2M were decreased	APOE could be a critical protein biomarker when tracking how meningiomas progress in the brain of an individual
Weston et al. (2011) [16]	To understand CSF analytic methods that improve the sensitivity of the diagnosis of brain cancer	Systematic review	Methods currently under research in CSF analysis	There are various methods such as flow cytometry, PCR, and analysis of other biomarkers that can be applied in tumor diagnosis	The effectiveness of early diagnosis implies a better prognosis, and CSF analysis methods lead to the early detection of brain tumors
Rajagopal et al. (2011) [17]	To demonstrate the feasibility of centrally collecting and processing high-quality CSF samples for proteomic studies within a multi-center consortium	Randomized controlled study	33 children with medulloblastoma and 25 age-matched control subjects.	PTGDS was discovered to be of lower amount in brain tumor samples by six-fold when compared to the control samples.	PTGDS can be an important biomarker of brain tumors
Araki et al. (2010) [18]	To identify novel biomarker candidate proteins differentially expressed in the CSF of patients with MMD using proteomic analysis	Randomized controlled study	20 persons suffering from MMD and 12 control subjects	34 protein biomarkers were identified in the CSF of MMD patients	The identified biomarkers have the capability to diagnose and classify MMD, which indicates that CSF proteins can be essential in diagnosis of brain conditions