Age is the most important risk factor for the development of cancer in dogs, for it is the aging that permits the long-term events leading to tumor development and progression to occur. For most tumor types, the risk for cancer increases with increased age. There are many types of cancer occurring in dogs such as: various types of skin tumors or carcinomas - tumors of the bone such as osteosarcoma - tumors of the lymphoid tissues such as lymphosarcoma - tumors derived from blood vessel such as hemangiosarcoma. To date, Swissys do not appear to be predisposed to a certain form of cancer. And although a few cases of cancer in young dogs have been reported, so far it is clearly the older population that is subject to the various forms of cancer.