The melanoma vaccine is another area where veterinary medicine is ahead of human medicine — and one that may have future human applications. Melanoma, a cancer of the melanocytes (pigment-producing cells), is one of the most common cancers found in dogs. Unlike in people, in dogs it has nothing to do with sun exposure and is usually found in the mouth. Since the melanoma vaccine is not preventive, the name is a bit of a misnomer, Proulx says. Sold under the trade name Oncept, it’s used to lengthen survival time after a patient has undergone surgery, chemotherapy or radiation. The treatment is a form of immunotherapy, in which a strand of DNA that’s encoded for a protein normally found only on melanocytes is injected into a dog. The protein stimulates an increased immune response in the dog, tricking its immune system into attacking the cancerous melanocytes. Oncept costs about $2,800 for a series of four shots.