Paired RNA-Seq Dataset Revealing Differential Gene Expression in Canine Transmissible Venereal Tumour: A Pilot Study

Abstract

Canine transmissible venereal tumour (CTVT) is a contagious cancer that uniquely regresses spontaneously following vincristine  chemotherapy. In this study, we analyzed a publicly available paired RNA sequencing dataset (SRA: ERR2044811-ERR2044822) comprising  tumour biopsies collected from CTVT-afflicted dogs at day 0 (pre-treatment) and day 28 (post-treatment). Raw reads were processed  with fastp for quality trimming and aligned to the canine genome (CanFam3.1) with HISAT2, followed by gene counting with HTSeq  and differential expression analysis via the DESeq2 pipeline. Principal Component Analysis (PCA) separated day 28 (regressing) samples  from day 0 (progressive) samples. We identified hundreds of differentially expressed genes (DEGs) (adjusted p-value <0.05) between  day 28 and day 0. Notably, immune-related chemokine genes such as CCL5 and CXCL10 were strongly upregulated at day 28, whereas  cell proliferation markers MKI67 and TOP2A were markedly downregulated in regressed tumours. These expression changes highlight  an activated immune response and reduced tumour cell proliferation during regression. Our findings corroborate the critical role of  host immunity in CTVT regression and identify gene expression shifts accompanying vincristine-induced tumour remission.