Brain Neoplasms

Brain neoplasms are divided into primary and secondary forms, with secondary disease arising from metastatic spread from solid tumors. For primary gliomas, the literature identifies a subset caused by Mendelian disorders, including neurofibromatosis, tuberous sclerosis, and Li-Fraumeni syndrome. Genomic analyses have also identified heritable risk alleles and molecular biomarkers associated with glioma risk and prognosis.

The literature emphasizes malignant progression, widespread invasion throughout the brain, and destruction of normal brain tissue, particularly in malignant astrocytic gliomas such as glioblastoma. Reported biological themes include altered signal transduction, gene expression regulation, transcriptome changes, DNA methylation, DNA mismatch repair, tumor microenvironment effects, tumor escape, and cell differentiation. Molecular features discussed in glioma include isocitrate dehydrogenase mutation and O6-methylguanine-DNA methyltransferase methylation, and immune-related mechanisms are also relevant through tumor-infiltrating lymphocytes and immunotherapy research.

Reported risk factors for glioma include Mendelian disorders such as neurofibromatosis, tuberous sclerosis, and Li-Fraumeni syndrome. Genome-wide association studies have identified heritable risk alleles associated with increased glioma risk. Molecular markers such as IDH mutation and MGMT methylation are discussed in the literature as biomarkers of prognosis rather than established general risk factors.

For brain metastases, surgery is a reasonable option, particularly for large tumors with mass effect, and symptomatic brain metastases should receive local therapy. The literature also discusses local therapy as the main approach for brain metastases, with deferral only in selected situations. For glioblastoma and other malignant primary brain tumors, current management includes targeted molecular therapies, agents targeting DNA damage response and metabolism, immunotherapies, and viral therapies, although outcomes remain poor.