Researchers have published a review in the journal Cell that explores how somatic mutations—genetic changes acquired by cells after conception—can influence disease processes, protect tissues, and identify new drug targets. The study analyzes recent findings on the role of these mutations in both healthy and diseased tissues.
Somatic mutations are common across healthy tissues, but most do not impact cellular behavior. However, some mutations affect important regulatory or coding regions in the genome, leading to changes in cell function. These changes can be subject to Darwinian selection, which allows certain cell clones with advantageous traits to expand or disappear based on their fitness.
"Somatic genomics uncovers the outcomes of evolutionary competitions within our tissues, which can drive disease, counter monogenic disease, or protect from common diseases," the authors state.
The review highlights that normal tissues often contain clones with positively selected "driver" somatic mutations. Some of these driver mutations overlap with those found in cancers, suggesting early cancer-related events may be detectable even before malignancy develops. Yet many driver mutations seen in normal tissue do not necessarily lead to cancer.
Diseases themselves create additional selective pressures that shape which mutant clones expand. Research indicates that diseases may select for different sets of driver mutations compared to those seen in cancers or healthy tissues, and clonal expansions tend to be larger in diseased organs.
The researchers also discuss how organ structure affects somatic diversity. For example, blood-forming (hematopoietic) cells face few physical barriers and allow beneficial mutations to spread widely. In contrast, liver cells (hepatocytes) are limited by anatomical boundaries that restrict clonal growth and can become further constrained by fibrosis during chronic liver disease.
Inflammation is identified as a factor promoting the expansion of certain mutant blood cell clones—a phenomenon called clonal hematopoiesis of indeterminate potential (CHIP). Experiments show that inflammation can stimulate growth of TET2-mutant cells through molecules like TNF-α and IL-6. Environmental carcinogens may also contribute by changing tissue environments rather than simply causing DNA damage; for instance, pollution-driven inflammation can promote lung cancer by encouraging expansion of pre-existing mutant KRAS clones.
The review notes that somatic mutations play roles beyond cancer. They have been implicated as drivers in autoimmune conditions and neurological disorders such as focal epilepsies. Malformations linked to abnormal brain development often result from somatic activating mutations affecting pathways like PI3K-AKT-mTOR. Vascular anomalies including arteriovenous malformations have been traced to RAS/MAPK pathway variants; rare skeletal disorders such as Maffucci syndrome and Ollier disease are associated with IDH1/IDH2 somatic changes.
Importantly, some adaptive somatic mutations help protect against disease or mitigate harmful effects at the cellular level:
"Many adaptive somatic mutations may counteract or mitigate disease-related cellular stress, offering potential treatment opportunities," the authors write.
In inflammatory bowel disease (IBD), recurrent somatic changes affecting IL-17 signaling appear to make intestinal cells more resistant to inflammation-induced damage. CHIP has also been observed to provide benefits: donor bone marrow containing CHIP-associated mutations can improve survival rates after transplantation and enhance responses to immunotherapy in some cancers. In cirrhotic livers, certain adaptive somatic variants boost cell survival and regeneration following injury—even though this does not always improve overall organ health.
Some adaptive mutations arise specifically under pressure from inherited (germline) genetic defects; these secondary changes can partially restore function lost due to monogenic diseases.
Cancer genome studies have provided a foundation for applying somatic genomics outside oncology by identifying genes under positive selection in diseased but non-cancerous tissues. The authors suggest a systematic four-step approach for using this knowledge: selecting target cells based on markers; sequencing their genomes; analyzing mutation patterns for candidate genes; and validating these findings experimentally as potential drug targets.
"A four-step framework to systematically identify somatic gene targets that impact disease and inform therapeutic strategies," they propose.
While promising for discovering new therapies and understanding disease mechanisms at a granular level, researchers caution that more experimental validation is needed before clinical applications are possible.
