Methylation profiling (DNA methylation classification)

What it is

Methylation profiling (DNA methylation classification) is an advanced laboratory test that analyzes the overall pattern of chemical marks (methylation) across a tumor's DNA. Because each tumor type tends to have a characteristic pattern — like a fingerprint — this profile can help classify brain tumors with high accuracy.

Understanding Methylation profiling (DNA methylation classification)

DNA methylation is a chemical modification that helps control which genes are active, and the genome-wide pattern of methylation differs characteristically between tumor types. Methylation profiling reads this pattern and compares it against reference databases of known tumor types, often providing a precise classification. It is especially valuable in difficult or ambiguous cases — where the appearance and standard molecular tests do not give a clear answer — and can sometimes reveal or confirm a diagnosis that would otherwise be uncertain. The 2021 classification recognizes methylation profiling as an increasingly important tool, and it is used in specialized centers. Understanding methylation profiling clarifies an advanced test that improves the accuracy of brain tumor diagnosis.

Why it matters

Understanding methylation profiling helps patients and families see how an advanced "fingerprint" test can improve diagnostic accuracy — clarifying or confirming a glioma's exact type, especially in difficult cases.