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CNS Cancer-Biomarker
By-Lovnish THAKURASU2014010100099Integrated Biotech4th sem
Introduction
• Central nervous system (CNS) lymphoma is a disease in which malignant (cancer) cells form in the lymph tissue of the brain and/or spinal cord
• Fatal Condition• x-rays, MRI and computed tomography (CT)
scans• Lack technique for early diagnosis
Protein Biomarker Identification in the CSF of PatientsWith
CNS Lymphoma
BACKGROUND
• Brain biopsy is often the testBrain biopsy is, however, associated with 1.2% to
7% risk of Hemorrhage
• Deep brain structures
• Diagnostic challenge
PURPOSE
• Elucidation of the CSF proteome may yield insights into the pathogenesis of CNS disease.
• Tested the hypothesis that individual CSF proteins distinguish CNS lymphoma from benign focal brain lesions.
• Noninvasive diagnosisEvaluation of the CSF is markedly less invasive than brain biopsy
and is standard of care
Technique Used
• Liquid chromatography/mass spectrometry• Identify several hundred CSF proteins in CNS
lymphoma • Used enzyme-linked immunosorbent assay
(ELISA) to confirm one of these markers • Use potential of mass spectrometry(MS)to
identify biofluid peptide profiles that might facilitate early diagnosis of cancer
Properties of CSF
• Volume of CSF -150 mL, compared with the 5-L blood volume.
• CSF compartment is specialized to CNS and is not exposed to the systemic circulation and to multiple organs.
• Both features favor the relative over representation of brain and brain tumor related proteins in the CSF.
Common Method
High-resolution two-dimensional (2D) polyacrylamidegel electrophoresis with MS for identification of excised gel spots.
• This process is limited by low sensitivity
In this an alternate strategy for differential proteomic analysis that also includes large-scale identification of more than 500 proteins to identify the major CSF proteins which distinguish B-cell CNS lymphoma from benign conditions.
METHOD
Obtain CSF
Centrifuged within 90 minutes
of collection to remove cellular
debris,stored at 80°C
2D LC/MS
analysis
Sample Preparation
3 mL of CSFAlbuminIgG, IgA,
Alpha-1 antitrypsinTransferrin
HaptoglobinWere depleted
CSF proteome wasDenatured Reduced Alkylated
After buffer exchange, digested, desalted
fractionated into three fractions on a strong cation-exchange 20 g of processed
peptidesDissolved in 0.1% formic acid injected into theLC/MS system
LC/MS Differential Quantification and Identification
Uses high-resolution LC/MS data for profiling differential quantification without isotopic labeling, combined with extensive protein identification by LC/MS/MS.Molecular Ion signal intensities were normalized
Approximately 500 proteins were identified by tandem MS using control CSF samples
All profiled molecular ions were additionally constrained when matched against the library via accurate m/z and chromatographic retention times.
Mostly concentration of Protein metabolite are affected
ResultCandidate biomarker that they pursued is the serine protease
inhibitor ATIII
Function-: ATIII is normally synthesized by hepatocytes and has an established role in the regulation of blood coagulation.
Demonstrated endogenous expression of ATIII RNA transcripts within diagnostic biopsy specimens of primary CNS lymphoma tumors.
Used immunoblot to confirm the high relative expression of ATIII protein in the CSF of CNS lymphoma patients
Reference
• Protein Biomarker Identification in the CSF of Patients With C
• https://www.researchgate.net/.../5790893_Protein_Biomarker_Identification
• Heart-cut 2D-LC/MS approach for pharmaceutical impurity
• https://www.agilent.com/cs/library/applications/5991-1873EN.pdf
Thank YOu