Mutational Signatures (v3.5 - November 2025)
SBS22b · GRCh37 · COSMIC v103
Mutational profile
Mutational profile using the conventional 96 mutation type classification. This classification is based on the six substitution subtypes: C>A, C>G, C>T, T>A, T>C, and T>G, as well as the nucleotides immediately 5’ and 3’ to the mutation.
Each of the substitutions is referred to by the pyrimidine of the mutated Watson—Crick base pair. Incorporating information on the bases immediately 5’ and 3’ to each mutated base generates 96 possible mutation types (6 types of substitution x 4 types of 5’ base x 4 types of 3’ base). Mutational signatures are displayed and reported based on the observed trinucleotide frequency of the genome, i.e., representing the relative proportions of mutations generated by each signature based on the actual trinucleotide frequencies of the corresponding reference genome.
Proposed aetiology
Aristolochic acid exposure. Found in many cancer samples that also have SBS22a, DBS20, and ID23.
Acceptance criteria
| Background | Identification study | First included in COSMIC | |
|---|---|---|---|
| Senkin et al. 2023 MedRxiv | v3.4 | ||
| Identification | NGS technique | Different variant callers | Multiple sequencing centres |
| WGS | Yes | Yes | |
| Technical validation | Validated in orthogonal techniques | Replicated in additional studies | Extended context enrichment |
| Yes | No | - | |
| Proposed aetiology | Mutational process | Support | |
| Aristolochic acid exposure | Statistical association | ||
| Experimental validation | Experimental study | Species | |
| - | - | ||
Summary of the technical and experimental evidence available in the scientific literature regarding the validation of the mutational signature.
Tissue distribution
Identified in clear cell renal cell carcinomas.
Associated signatures
SBS22b is associated with SBS22a, and these signatures are commonly found in the same samples, although individuals with only SBS22b have been identified. SBS22b is also associated with DBS20 and ID23.
Differences between current and previous profiles
The cosine similarity between SBS22 and SBS22b is 0.84.