Mutational Signatures (v3.5 - November 2025)

Mutational profile

Overview of the SV32 classification schema. The classification schema bins all SVs, apart from translocations, according to the size of the event in base pairs: 0–10kb, 10kb–100kb, 100kb–1Mb, 1Mb–10Mb, and >10Mb. Translocations, which may involve more than one chromosome, are not binned by size because they can be either balanced (where there is no net loss of genetic material on the chromosomes involved and thus the size can be described by one number) or unbalanced (where there is a net loss or gain of genetic material on the chromosomes involved and thus the sizes of the segments cannot be described by just one number). Note that whether a translocation is balanced or unbalanced is not considered in this classification schema. The different types of SVs are then further divided into clustered and non-clustered events to account for the non-random distribution of these events along the genome. Clustered events are defined as events that occur closer to each other on a chromosome than purely expected by chance.

Proposed aetiology

Unknown.

Comments

SV9 comprises a mix of medium to large complex rearrangements, with fewer simple rearrangements. These rearrangements include deletions, tandem duplications, and inversions. SV9 was detected in most tumour sites but was absent in sarcoma, testicular, and uterine cancers. The signature has been previously identified independently in Degasperi et al. 2020 (RefSig R6b).

Acceptance criteria

Summary of the technical and experimental evidence available in the scientific literature regarding the validation of the mutational signature.

Tissue distribution

Detected in most tumour sites but was absent in sarcoma, testicular, and uterine cancers.