Veterinary researcher examines malignant melanoma in horses and people

Malignant melanoma is a dangerous, aggressive form of cancer, and approximately 54,000 new cases are diagnosed every year, according to the American Cancer Society. Interestingly, there are many similarities between malignant melanoma in horses and malignant melanoma in people.

Recognizing the extraordinary opportunity for translational research that the disease represents, Dr. John Robertson, a professor in the Virginia Maryland Regional College of Veterinary Medicine’s Department of Biomedical Sciences and Pathobiology at Virginia Tech, and director of the college’s Center for Comparative Oncology (CECO), has been looking at one experimental treatment.

During a recent presentation made before a regional meeting of the American Cancer Society in Roanoke, Robertson discussed his use of Frankincense oil as a possible treatment for malignant melanoma in horses.

The risk factors for malignant melanoma in people and horses are very similar, according to Robertson. In people, they include pale complexion and hair, exposure to excessive sunlight and sunburns, and aging. Horses at risk also have a pale coat of grey to white, and there seems to be a correlation to aging, which could be a result of chronic exposure to sunlight. In each, the disease is an infiltrated pigmented malignancy that is difficult to manage. Conventional therapies include chemotherapy, radiation, immunotherapy, and surgery.

The disease often affects horses with the development of lesions on the lips, neck, and perineal area.

During his presentation, Robertson detailed the story of Chili, a handsome, 11-year old Thoroughbred and champion jumper that was diagnosed with multi-centric malignant melanoma at the age of 7. Told by her local practitioner that there was not much that could be done for Chili, and aware of an interest Robertson had in evaluating an experimental therapy, Chili’s owner contacted Robertson and asked if he would work with Chili.

That experimental therapy involved the use of frankincense oil, a compound known as a valuable treatment for wounds for more than 2,000 years, and one people are reminded of every Christmas when they recall the Gifts of the Magi that were brought to the Christ-child.

Frankincense oil is a fragrant botanical oil distillate made from fermented plants, explains Robertson, who adds that it contains hundreds of constituents, including boswellic acid, a component that is known to have anti-neoplastic properties. Scientists have demonstrated that the oil has potent anti-inflammatory effects and anti-tumor properties when evaluated in tissue culture with tumors such as astrocytomas, melanomas, and fibrosarcomas. Furthermore, it appears to have fairly selective anti-tumor activity and does not appear to disrupt normal cells. But much about how it affects actual cancer patients is unknown.

Chili’s experimental protocol involved daily injections of medicinal grade, sterile frankincense oil directly into his tumors, plus application of oil on his topical tumors. Throughout the experiment, Chili’s comfort and well-being was carefully maintained through pain and nutritional management, including copious amounts of his favorite peeled baby carrots and peppermints.

The lesions were observed, measured, photographed, and periodically biopsied, according to Robertson. Those tumor biopsies demonstrated that some small tumor cells were destroyed by the treatment and those treated topically were reduced in size. Unfortunately, however, Chili passed away on Oct. 18, 2005 as a result of the progressive and relentless growth of the non-treated tumors.

Robertson believes that Chili’s involvement with the Center for Comparative Oncology and the experimental protocol did result in some important achievements.

“I think this research on frankincense oil suggests that this ancient medicine may have significant modern uses for chemotherapy of non-resectable malignancies,” said Robertson. “This research showed that equine melanomas respond to this therapy.”

Dr. Edward Shaw, professor and chairman of the Department of Radiation Oncology at the Wake Forest University School of Medicine, recently spent a day on campus visiting Robertson’s lab.

“I find both the differences and similarities between human and equine melanoma quite fascinating to see,” wrote Shaw in a communication to Robertson.

Shaw, who also directs the Clinical Research Program at Wake Forest University’s Comprehensive Cancer Center, discussed future areas of collaboration between the Virginia Maryland Research Center of Veterinary Medicine and Wake Forest University during the visit.

Information gleaned from this Phase I-II National Cancer Institute (NCI) format clinical trial has supported the development of three new grant applications and helped in the treatment of five additional horses, Robertson said.

The Virginia-Maryland Regional College of Veterinary Medicine (VMRCVM) is a two-state, three-campus professional school operated by the land-grant universities of Virginia Tech in Blacksburg and the University of Maryland at College Park. Its flagship facilities, based at Virginia Tech, include the Veterinary Teaching Hospital, which treats more than 40,000 animals annually. Other campuses include the Marion duPont Scott Equine Medical Center in Leesburg, Va., and the Avrum Gudelsky Veterinary Center at College Park, home of the Center for Government and Corporate Veterinary Medicine. The VMRCVM annually enrolls approximately 500 Doctor of Veterinary Medicine and graduate students, is a leading biomedical and clinical research center, and provides professional continuing education services for veterinarians practicing throughout the two states.