More than 50% of dogs older than 10 years of age will likely develop cancer. Only two small-molecule drugs have been approved to specifically treat canine cancer. However, no drugs for cats are currently available. The most common form of cancer in dogs and cats is multicentric lymphoma with affected organs such as lymph nodes, spleen and liver. It actually accounts for 85% of cancer cases in the dog. The incidence of cancer is likely to increase in future as the companion animals further age. Mortality rates are high, between 14% and 27% of dogs die of cancer. As dogs are susceptible to the same types of cancer as humans, clinical successes seen with human diseases can be replicated and adopted to animal health drugs. Experimental and clinical studies have identified a number of key biological molecules involved in controlling the development and spread of cancer. These molecules are ideal targets for antibody based therapies. Indeed, in humans, efficacy, safety and profound commercial successes have been demonstrated with monoclonal antibodies that target these factors. Such molecules also represent ideal targets for our virus-like particle vaccine technology. Our cancer projects HP011 and HP012 are currently in the early phase of lead generation.