Brain tumor markers: what tests help to suspect oncology

«MRI is not always the first.» Why laboratory diagnostics are important in neuro-oncology

Most patients associate brain tumors exclusively with magnetic resonance imaging. However, in some cases, even before the appearance of imaging changes, it is possible to detect tumor markers — specific or nonspecific proteins, metabolites or mutations, which are produced by the tumor itself or by the immune system in response to its presence. Their study is an important part of comprehensive diagnostics and monitoring brain tumors.

What are brain tumor markers?

Brain tumor markers are substances that can be detected in blood, cerebrospinal fluid, or tissues, and be associated with the presence of a neoplasm. They are classified by origin:

• Systemic tumor markers – circulate in the blood

• Local (in the cerebrospinal fluid) – reflect changes in the CNS

• Genetic/molecular – tumors are detected in the biopsy

Although There is no universal marker for brain tumors., their combination helps to estimate type, prognosis, treatment effectiveness and risk of recurrence.

Key laboratory markers associated with brain tumors

1. NSE (neurospecific enolase)

• Increases with neuroblastomas, glioma, medulloblastoma

• Often used for monitoring the effectiveness of treatment

2. S100B

• Protein produced by astrocytes

• High levels may be associated with high-grade gliomas

• It also increases with CNS injuries, therefore requires differentiation

3. GFAP (glial fibrillary acidic protein)

• It is detected in the cerebrospinal fluid when glioblastoma

• Indicator glial cell damage

4. β2-microglobulin

• Increases with CNS lymphomas

• Can be used as an additional prognostic marker

Molecular markers in brain tumor tissues

After biopsy or surgical removal of the neoplasm, molecular genetic testing is performed. The most important markers are:

These markers help personalize treatment and choose the most effective therapy.

When are brain tumor marker tests prescribed?

• If there is clinical symptoms (headache, vision changes, seizures) without an obvious cause

• At suspected metastases into the brain from another primary focus

• In patients with increased intracranial pressure

• After surgical removal of the tumor - for relapse monitoring

• In progress monitoring the effectiveness of chemotherapy or radiation therapy

What limits diagnostics to markers alone?

• Low specificity — many markers are elevated in non-oncological conditions

• Lack of a universal marker — combination required

• Does not replace MRI/CT, but only complements the clinical picture

• Molecular tissue diagnostics available only after biopsy

What other tests might be appropriate?

• UAC, SRB – assessment of general condition

• Spinal puncture – for CSF examination in case of suspected meningeal metastases

• Genetic analysis of tumor tissue – after removal or biopsy

Tumor markers are not the answer, but hint, where to look next. It is the comprehensive approach — laboratory + visualization + clinic — that allows you to accurately assess the situation.