Like their owners, dogs and cats can be affected by several types of cancer, and some types are very similar to those seen in people. Unfortunately, there is still no cure for several types of cancer. How can humans’ best friends help? If a new therapy to fight cancer works well in pets, it is likely to also be effective in people with the same type of cancer. Scientists, medical doctors, and animal doctors are working together to develop new therapies that destroy cancer cells and save patients. Since the characteristics of certain types of cancer are very similar between humans and pets, new medicines that work in pet dogs or cats may also benefit human patients. Studying these “human-like” cancers in pets may speed up the development of effective anti-cancer drugs and will help to cure not only more dogs and cats, but also people with cancer.