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Tumor Discovery Enhanced SV analysis in WGS

merging the results from different callers and improving Table 1. Example of translocation events between
the accuracy of downstream analyses. chromosome 1 and chromosome 2
2. The package Breakpoint 1 Breakpoint 2
Chromosome Position Chromosome Position
SVs are a crucial aspect of genetic analysis, but they
can be detected in distinct ways by different callers. The chr1 98723726 chr2 115114422
standard output format is the variant call format (VCF) chr1 177408163 chr2 106068260
file, and SVIV requires users to provide a metadata file chr1 175681463 chr2 235063885
with sample IDs and directory information for each VCF chr1 133482761 chr2 196041561
file to compare the results of different callers. The union chr1 153232808 chr2 156545196
and intersect operators are used to merge the results for chr1 208692183 chr2 108799960
DEL, DUP, INS, and INV. For translocations, each one can chr1 76442144 chr2 158594727
be converted into a point in a Cartesian coordinate system, chr1 162087941 chr2 9581976
and clustering methods like K-means can be used to merge
them. The package also provides visualization functions chr1 142091374 chr2 16000994
for displaying the results. chr1 179281809 chr2 43047012
chr1 138680310 chr2 80397812
It is noteworthy that each caller has its pipeline for
detecting and filtering SVs; hence, users must run their chr1 103764557 chr2 207420
selected callers before running SVIV. At present, SVIV has chr1 204714860 chr2 168075552
been extensively tested with four common callers: Manta , chr1 183159240 chr2 238798497
[8]
DELLY , LUMPY , and GRIDSS (GRIDSS2) [11,12] . It chr1 41036298 chr2 222120683
[9]
[10]
should be noted that using VCF results from other callers chr1 136739638 chr2 136157351
may lead to errors or unexpected outcomes. However, the chr1 146398781 chr2 172967853
authors of SVIV are actively working toward expanding chr1 7634457 chr2 122904530
the scope of tested callers and providing support for
additional callers in future releases. This ongoing effort chr1 129841966 chr2 12950544
aims to enhance the compatibility and versatility of SVIV, chr1 118481240 chr2 33891457
thereby accommodating a broader range of SV detection
pipelines for the benefit of users. of the intersection and union operations on three callers.
The example displays the merged results of three callers
2.1. Intersection and union operation for merging using different combinations of operations. Figure 2A
DEL, DUP, INS, and INV
emphasizes that the merged results can differ significantly
DEL, DUP, INS, and INV are SVs that are defined within based on the merging strategy used.
a genomic region, and each of these mutations can be
identified by a region annotation using chromosome i: 2.2. Merging translocation through projection
[start, end]. When dealing with results from multiple Translocations are rare inter-chromosomal mutations that
callers, the intersection (%I%) and union (%U%) may have a significant impact on the genome. In typical
operators are used to merge these results. The SV set can scenarios, translocations identified by different callers can
be represented in the following manner: be directly merged for downstream analysis. However, there
[14]
startend , startend , , exists a distinct phenomenon known as chromothripsis ,

,
,

SV callertypesample, , 1 1 2 2 , which involves extensive translocations occurring in a
starrt end, n single catastrophic event. This event leads to the highly

n
heterogeneous detection results of multiple translocations
Where type ∈ {DEL, DUP, INS, and INV}, caller refers by callers, which pose challenges for downstream analysis.
to the name of the program used for detecting SVs, Therefore, it is vital to acknowledge the significance
while sample refers to the unique identifier assigned to a of chromothripsis and its potential ramifications on
particular sample in the dataset. There is no overlapping translocation analysis when merging translocation outputs
between regions [start i, end i] and [start j, end j], where obtained from multiple callers. Careful consideration of
i ≠ j. Merging results from different callers involves using chromothripsis is essential to ensure accurate interpretation
intersection and union operations on two SV sets to and meaningful insights during the consolidation of
obtain a merged result. Figure 2A provides an illustration translocation data from various sources.
Volume 2 Issue 2 (2023) 3 https://doi.org/10.36922/td.0894