Brain Tumor: An Overview of Introduction, Types, Pathogenesis, Lab Diagnosis, Treatment, Prevention, and Keynotes

Introduction

A brain tumor is an abnormal, uncontrolled growth of cells within the brain or its surrounding structures. Brain tumors may be primary (originating in the brain) or secondary (metastatic), spreading from other organs. They can affect individuals of any age and cause significant neurological morbidity.

Types of Brain Tumors

1. Primary Brain Tumors

• Gliomas (astrocytoma, glioblastoma, oligodendroglioma)
• Meningioma
• Pituitary adenoma
• Schwannoma
• Medulloblastoma
• Ependymoma

2. Secondary (Metastatic) Brain Tumors

• Metastases from lung, breast, melanoma, kidney, and colon cancers

Pathogenesis

Brain tumor development involves genetic and molecular alterations leading to uncontrolled cell proliferation:

• Activation of oncogenes (EGFR, BRAF)
• Inactivation of tumor suppressor genes (TP53, RB)
• IDH mutations in lower-grade gliomas
• Abnormal signaling pathways (PI3K/AKT/mTOR)
• Tumor-induced angiogenesis and blood–brain barrier disruption

Laboratory Diagnosis

• Neuroimaging: MRI with contrast (gold standard), CT scan
• Histopathology: Tumor grading and classification (WHO classification)
• Immunohistochemistry: GFAP, Ki-67, IDH1, p53
• Molecular testing: IDH mutation, 1p/19q co-deletion, MGMT methylation
• CSF examination (selected tumors)

Treatment

• Surgical resection (maximal safe removal)
• Radiotherapy
• Chemotherapy (temozolomide)
• Targeted therapy and immunotherapy
• Steroids for cerebral edema
• Antiepileptics for seizure control

Prevention

• Avoidance of ionizing radiation
• Use of protective measures in occupational exposure
• Early evaluation of persistent neurological symptoms
• Genetic counseling in familial tumor syndromes

Keynotes

• Brain tumors may be benign or malignant, but both can be life-threatening.
• MRI is the imaging modality of choice.
• Molecular profiling guides prognosis and therapy.
• Multidisciplinary management improves outcomes.
• Early diagnosis is critical for better survival and quality of life.

Further Readings

1. https://mayfieldclinic.com/pe-braintumor.htm
2. https://en.wikipedia.org/wiki/Brain_tumor
3. https://my.clevelandclinic.org/health/diseases/6149-brain-cancer-brain_tumor
4. https://www.mayoclinic.org/diseases-conditions/brain-tumor/diagnosis-treatment/drc-20350088
5. https://www.cancer.org/cancer/types/brain-spinal-cord-tumors-adults/causes-risks-prevention/prevention.html
6. https://www.compassoncology.com/brain-cancer/causes-risk-factors-and-prevention
7. https://www.apollo247.com/health-topics/brain-tumor
8. https://braintumor.org/news/what-to-expect-radiation-therapy-as-a-patient-with-a-brain-tumor
9. https://iconcancercentre.com.au/conditions/brain-cancer/treatment/
10. https://int.livhospital.com/habits-that-cause-brain-tumors-the-shocking-truth
11. https://ijcap.in/html-article/20276
12. https://pubmed.ncbi.nlm.nih.gov/29371158
13. https://rarediseases.org/rare-diseases/medulloblastoma
14. https://www.medanta.org/pillar/brain-tumour-types-symptoms-causes-stages-treatment