2. Labrador Retriever

Friendly and loyal companions, Labrador Retrievers make wonderful family pets, service animals, and hunting dogs. This dog is also America’s number one breed. However, not many people know that these lovely dogs have pretty high rates of cancer. Specifically, a Labrador Retriever is prone to lymphoma, which is known to affect this breed more than any other (including the Golden Retriever).

Another type of cancer commonly diagnosed in these guys is hemangiosarcoma, a cancer of the blood vessels. These two types of cancer can be pretty aggressive and, if left untreated, can lead to death in a very short period of time.