A recent study compared the cancer genomes of a rare form of melanoma, mucosal melanoma, in humans, dogs, and horses in order to see how this type of cancer acts across the phylogenetic tree. This is the first time this type of comparison has been done and it is hoped that the results of this study will be translatable to better treatment outcomes in humans. Dr. David J. Adams and colleagues from the Wellcome Trust Sanger Institute of Cambridge, UK, published their data in the journal Nature Communications.
Mucosal melanoma is a rare form of melanoma associated with skin cancer. It is so rare that only around 154 of the 15,400 people diagnosed with melanoma in the UK this year will be diagnosed with mucosal melanoma. That is about 1%. This form of cancer arises from the melanocytes, which are found not only in the skin but also mucosal surfaces of the body, such as the sinuses, nasal passages, mouth, vagina, and anus. Interestingly, this type of skin cancer is unrelated to UV light exposure and typically does not present itself until the cancer is already in a late stage of progression.
When the researchers sequenced tumor-germline pairs from 46 primary human mucosal, 65 primary canine oral and 28 primary equine melanoma cases they found a recurrent number of genetic alterations, specifically the driver genes MDM2, B2M, KNSTRN, and BUB1B. These genetic mutations were found across all species compared.
What these findings tell us is that the genetic mutations that matter most to mucosal melanoma are the ones that have been conserved across species. These results demonstrate, according to Dr. Adams, who spoke with Science Daily, "These key mutations are likely to drive the cancer and could be targets for the development of new drugs".
Researchers found similarities in the mutation profiles both in terms of the mutated driver as well as mutation number. These profiles can influence tumor behavior and response to treatment. These revelations also exposed several differences across the species. Most importantly, from a research perspective, they found that the genomes of canine melanomas lacked mutations in other key human mucosal melanoma drivers, such as SF3B1 and ATRX.
This is important to consider since dogs are often used as an animal model for melanoma. Various treatment techniques are used on dogs first to see if they will have any impact on human melanoma. The lack of complete overlap may suggest that the dog may not the best model for mucosal melanoma. Thus, these data could be used to help inform studies investigating disease pathology as well as reveal potential therapeutic treatments.