Cancer represents a major global challenge for medical practice in humans and companion animals. A plethora of basic and preclinical studies involving cell cultures and animal models have screened novel anti-cancer drugs and innovative treatments such as immunotherapy and gene-based therapy.

In addition, emerging alternative translational models based on comparative oncology have shown promising results in anti-cancer drug discovery since companion animals develop spontaneous tumors and share the same environment as humans. Nonetheless, some gaps still exist in pre-clinical and clinical comparative animal models in terms of biological behavior, genetics, molecular pathways, as well as the immunological features of cancer that should be fulfilled to enhance their translational value.

This Special Issue of Cancers contributes high-quality scientific evidence through novel data from preclinical and clinical studies performed in humans and/or animals. Thus, we hope that this set of articles will increase readers' knowledge within the scope of comparative and translational oncology and encourage further research into these innovative anti-cancer therapies.

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