Molecular / genetic testing

What it is

Molecular (genetic) testing analyzes a glioma's genetic and molecular features — such as IDH status, 1p/19q codeletion, MGMT methylation, and others — performed on tissue from a biopsy or surgery. It is now essential for accurate diagnosis and for selecting treatment.

Understanding Molecular / genetic testing

In modern glioma care, the diagnosis is not complete without molecular testing. These tests identify the specific genetic and molecular alterations that define the tumor type and grade (as in the integrated diagnosis), predict behavior and outcome (prognostic markers), and guide treatment (predictive markers and targetable changes). For example, IDH status determines the tumor category, 1p/19q codeletion distinguishes oligodendroglioma, MGMT methylation guides chemotherapy decisions, and findings like BRAF V600E may open targeted therapy options. Molecular testing uses various methods — immunohistochemistry, sequencing, and sometimes methylation profiling — performed on the tumor tissue. Because so much depends on these results, obtaining adequate tissue and performing comprehensive testing (often at or in consultation with specialized centers) is important. Understanding molecular testing in gliomas clarifies why analyzing a tumor's molecular features is now central to care.

Why it matters

Understanding molecular testing helps patients and families see why analyzing a glioma's molecular features is now essential — it defines the diagnosis, predicts behavior, and guides treatment, including targeted options.