Cancer in Black Horses

[JOJOBA]

About 4 months ago. My horse got a lump on his dock recently which meant we had to have the end of it amputated. When the test results on it came back they confirmed it was a melonoma and therefore that my horse had skin cancer.
He is 12 years old approx and fit and healthy. However he is black, with black skin. Apparantly 80% of grey horses with pink skin over 15 get this type of cancer, but my horse has also got it in an area which gets 0 sunlight.
I was just wondering if anyone else has had experience of anything like this? I check him regularly for lumps and he seems fine, and my vet suggested that some vets have a theory that black skinned horses may be prone to 'harmless' melonomas in the dock.
Anyone any ideas?
xxx

[alwaysfallingof]

Not all skin cancer is related directly to sunlight exposure. Because the skin epidermis cells divide so quickly then they are at a higher risk of mutations that could ultimately lead to a tumour growing in the area than in some other tissues. So it is possible for them to get tumours in places on their skin that are unexposed to sunlight, it's just less likely.

[JOJOBA]

Okay Im only parroting what my vet said:P
Anyone else?
xxx