Molecular & Genetic Markers
Hypermutation / mismatch repair deficiency
Hypermutation is an unusually high number of mutations in a tumor, sometimes from a defect in DNA repair, which can affect treatment and may indicate an inherited condition.
In short: Hypermutation / mismatch repair deficiency
- It is an unusually high number of mutations in a tumor.
- It can result from a defect in DNA mismatch repair.
- It can make tumors resistant to some chemotherapy.
- It may indicate an inherited cancer-predisposition condition.
What it is
Hypermutation is the presence of an unusually high number of genetic mutations in a tumor. In gliomas, it can result from a defect in the DNA "mismatch repair" system (the cell's spell-checker for DNA), and it has implications for treatment and, sometimes, for inherited cancer risk.
Understanding Hypermutation / mismatch repair deficiency
The mismatch repair system normally corrects errors that occur when DNA is copied. When this system is deficient, errors accumulate, producing a hypermutated tumor with many mutations. In gliomas, hypermutation can arise from an inherited condition (such as constitutional mismatch repair deficiency or Lynch syndrome) or can develop after treatment (for example, in some tumors after temozolomide). Hypermutation has practical importance: it can make tumors resistant to certain chemotherapy, and it is being studied as a potential indicator of response to immunotherapy. When hypermutation suggests an underlying inherited condition, genetic evaluation may be warranted, with implications for the patient and family. Understanding hypermutation clarifies a feature of some gliomas that affects treatment and can point to inherited risk.
Why it matters
Understanding hypermutation helps patients and families see why a tumor with many mutations matters — it can affect treatment response, is studied for immunotherapy, and may point to an inherited condition worth evaluating.
Common questions
What is hypermutation?
An unusually high number of mutations in a tumor.
What can cause it?
A defect in DNA mismatch repair, inherited or acquired.
Why does it matter?
It can affect treatment and may indicate an inherited condition.
Bottom line
Hypermutation is an unusually high number of mutations, sometimes from a DNA-repair defect, that can affect treatment and may indicate an inherited cancer-predisposition condition.
Browse all 265 Glioma definitions
Read the Glioma patient guides
Not sure which page you need? Put words to it with the symptom navigator