Germline gene fusions across species reveal the chromosomal instability regions and cancer susceptibility

The canine transmissible venereal tumor (CTVT) is a clonal cell-mediated cancer with a long evolutionary history and extensive karyotype rearrangements in its genome. However, little is known about its genetic similarity to human tumors. Here, using multi-omics data we identified 11 germline gene fusions (GGFs) in CTVT, which showed higher genetic susceptibility than others. Additionally, we illustrate a mechanism of a complex gene fusion of three gene segments (HSD17B4-DMXL1-TNFAIP8) that we refer to "greedy fusion". Our findings also provided evidence that expressions of GGFs are downregulated during the tumor regressive phase, which is associated with DNA methylation level. This study presents a comprehensive landscape of gene fusions (GFs) in CTVT, which offers a valuable genetic resource for exploring potential genetic mechanisms underlying the development of cancers in both dogs and humans.