Somatic genomic alterations (SGA)

Somatic genomic alterations (SGAs) are non-heritable changes in the DNA sequence that occur in somatic cells after conception, distinguishing them from germline mutations (National Cancer Institute, 2023). These alterations encompass a wide range of genetic changes, including single nucleotide variants, small insertions and deletions, copy number variations, and large-scale structural rearrangements such as chromosomal translocations (Nature Reviews Genetics, 2019). While many SGAs are benign "passenger" mutations, "driver" alterations in oncogenes or tumor suppressor genes are the primary cause of cellular transformation and cancer progression (Science, 2015). In the context of precision medicine, specific somatic alterations—such as the BRAF V600E mutation or the BCR-ABL1 fusion—serve as critical therapeutic targets for small-molecule inhibitors and monoclonal antibodies (Journal of Clinical Oncology, 2020). Additionally, the overall burden of these alterations, known as Tumor Mutational Burden (TMB), is used as a biomarker to predict response to immune checkpoint inhibitors (Nature, 2017). Because the term "Somatic genomic alterations" refers to a broad class of genomic events rather than a single protein or receptor, it is considered a pathological category rather than a discrete therapeutic target.

Other names

Somatic mutationsAcquired mutationsSomatic variantsTumor mutationsGenomic alterationsAcquired genomic variants

Drugs target the functional consequences of specific alterations, such as inhibiting constitutively active mutant kinases, inducing synthetic lethality in cells with DNA repair defects, or utilizing high mutational loads to enhance immune checkpoint blockade efficacy.