Although rivoceranib showed anti-proliferative effects against canine tumour cell lines (LMeC and CHMp) in vitro, it was difficult to evaluate whether these effects were associated with the VEGFR2 pathway because the canine tumour cell lines used in this study showed minimal expression of VEGFR2 in vitro (Supplementary Figure S1). This evidence concerns the gene KDR and neoplasm.