Hypermutated Tumor
Malignancy characterized by an unusually high mutation rate, often associated with defective DNA repair mechanisms and enhanced immunogenicity.
Full Definition
A hypermutated tumor contains significantly more somatic mutations than typically observed for its cancer type, usually defined as more than 10-20 mutations per megabase of DNA. This phenotype commonly results from deficiencies in DNA mismatch repair systems, POLE/POLD1 mutations, or exposure to mutagenic agents. Hypermutated tumors often display increased neoantigen load, making them more recognizable to the immune system and potentially more responsive to immunotherapy approaches. The identification of hypermutation status has become an important biomarker for treatment selection, particularly for immune checkpoint inhibitor therapy, and may influence prognosis across various cancer types.
Usage
Usage note: Often hyphenated when used as a compound adjective.
In Context
- "Genomic profiling identified this colorectal cancer as hypermutated, with over 50 mutations per megabase." — Molecular pathology report
- "Patients with hypermutated tumors showed significantly higher response rates to PD-1 inhibitor therapy." — Clinical research publication