Melanomas?

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Shilasdair

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As the owner of a grey, I am just interested in melanomas.
Can anyone tell me the probability that she will have melanomas, or more about the genetic heritability of them? Or any experiences of your own greys with melanomas?
Thanks.
S
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This is something I'm also interested in - I have a 10 year old grey mare. How old is yours?
My vet book just says that they are tumours and are most common in elderly grey horses (does not say what they class as 'elderly'). Most common sites are under the dock, around the anus, vulva or sheath and on the head. Treatment is only required if they ulcerate and become infected. The worrying thing the book says is that occasionally they spread rapidly throughout the body and in these cases the prognosis is hopeless.
I think from now on as my girl gets older I'll get the vet to check her for melanomas when he/she is doing her annual vaccinations.
 
Mine is only 3yo, but my mother is smitten with her, and has read some article suggesting death is imminent for all greys.
I suppose you'd be able to check for external melanomas yourself...and internal ones wouldn't be picked up by a vet examination....
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chances are very high,. normally they develope later in life.. ie over ten.

they can be removed,

if a horses melanoma turns to cancer it is 99% of the time fatel.
 
Funny you should post this as I was checking the new grey (10 yrs old) for them yesterday. He hasn't got any but I will be keeping an eye open for any lumps forming. I knew of an old old pony that had so many under his dock I don't know how he managed to poo.
 
Well we have a 34 year old grey on our yard and has never had any melanomas. And we have about 6 greys over 15 years old that havent had any either.
 
The external ones are not always that obvious - the vet found one on an old pony at our yard - it is just behind the wither (unusual place for one) and is just a slightly raised area. TBH I would just have assumed it was uneven muscle development or something. That's why I was thinking about getting mine checked by a vet, in case she has any like this that are not obvious. I wouldn't get a vet out just to do this, only if they happen to be out for something else such as vaccinations. Its good to hear that some greys on here have not developed them. Its not something that would have put me off getting a grey (too late for that now anyway she's here to stay!)
 
you sarcasium o great one is going over my head..

it was intresting... but nothing new in it, if you know what i meen.
 
Cpt Horace Hayes
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comments that " it has been said that all grey horses will eventually develop them if they live long enough"

Although they are classed as tumours they are mostly benign, Malignant ones are rare but if they do happen they tend to spread through the internal organs agressively and are untreatable.
My grey mare has a large one at the end of her dock and a few smaller ones around her anus, she's 13. small git pony who is 12 has none, i was actually pondering earlier today if horses are more prone than ponies
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An old mare I had, estimated at 17 had them around her vulva, dock and cheek.
Unfortunately it was discovered, after she was PTS following untreatable colic that she had internal ones growing in places that were restricting her bowel.
It is not necessarily the ones you can see that do the damage.

It hasn't put me off greys and I have more now. My current 11 yr old mare isn't showing any signs of them.
 
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you sarcasium o great one is going over my head..

it was intresting... but nothing new in it, if you know what i meen.

[/ QUOTE ]

No sarcasm, just badly worded on my part.
What I meant was that I should do a search online through one of the ScienceDirect type databases which publish scientific papers on such things - usually lurking in Equine Vet Journal.
I didn't mean papers as in newspapers...
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I know nothing more than has already been written...
I have a 14 yr old grey Welsh A... she has many melanoma's..they first appeared about 3 yrs ago. She has them on her anus, vulva, under her dock, between her teats and has one on her ear.. They're all approx the size of a pea..I've just been told to keep an eye on them for any major change..
 
Always prefered grey horses, so from my limited experience with them I'd say that 99.9% have some sort of melanoma. My old mare in her 40's has lots under her tail, they are increasing in number and size but don't seem to bother her and the vet assures me that the melaomas wont be the cause of her demise
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. Alex (the Arab), on the other hand had one appear when he was about 3 years old but died from colic caused by internal growths at 17
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. Other greys I've had have had one or two melanomas, but nothing too extreme and haven't been a problem.
 
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pmsl i am very sorry... i am clearly being a retard... (will blame it on a crap day)

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My fault, sorry. I am writing in strange pidgin English today, for some reason. I think my head was fried in the sun.
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THIS SEEMS TO BE THE MOST INTRESTING YET....

A recent Austrian study has shown that melanomas in gray horses are less malignant than those found in solid-colored horses characterized by early metastases (cancer that started from cancer cells from another part of the body). Researchers believe this might be because gray horses have specific genetic factors that inhibit the metastatic processes. Also, the researchers found that the heritability of melanomas in a gray horse population is about 30%.

The study, published in the Equine Veterinary Journal, was completed by researchers from the University of Veterinary Medicine in Vienna, Austria (VUW), collaborating with individuals from the University of Agriculture and University of Vienna Medical School, and the University of Zagreb in Croatia.

The scientists performed a clinical study on 296 gray Lipizzaners with pedigrees traced back 32 generations. Each was classified according to his stage of disease using a 0-5 scale (0 being free of melanoma).

"Of the 296 horses, dermal melanomas were present in 148 horses (50%)," said the study. Of 228 horses younger than 16, 43% were melanoma-bearing, while 75% of the 68 horses 16 years old and older had melanomas. In 75.6% of the horses with melanomas, tumors were found under the tail.

The scientists also analyzed the effects of stud farm, age, and sex on melanoma incidence. While the animal's sex didn't seem to be a factor for incidence, the effects of stud farm and age were highly significant. Horses from particular stud farms had significantly lower melanoma gradation than horses from other farms.

Although melanoma-bearing gray horses were found up to stage 4, none of the affected horses suffered any severe clinical effects or was handicapped in performance. This contrasts with solid-colored horses with melanomas. Monika Seltenhammer, DVM, of the Clinic for Surgery and Ophthamology of VUW, said, "Although melanomas are more seldom in dark-colored horses, they show human melanoma-like features. And melanomas in humans are one of the most malignant tumors due to the early development of metastases."

Melanomas have been scientifically linked to gray horses before; similar results were found in a 2000 study using Camargue-type (from Southern France) gray horses, thus giving the current study results more significance. Interestingly, the Lipizzaners had more incidence of melanoma than the Camargue horses, and the former is the product of 400 years of inbreeding, whereas the Camargue population is more heterogeneous. The authors suggest that, "A hereditary predisposition (due to inbreeding) seems probable," although another 2000 study reported that Lipizzaner inbreeding has no effect on melanoma incidence.

Further analysis of melanoma development is needed to indicate whether the tendency to develop melanomas is due to parentage or an influence of genes with vigorous effects that are unique to gray horses.

"On the one hand, the gene which is responsible for graying seems to be connected with the development of melanomas in such horses," she said. "Whereas on the other hand, there are existing grays, old and white ones, without any melanomas. So there are obviously more genes responsible that are affecting and influencing each other, and it depends on which genes are more expressed."

Regardless of their derivation, "A histological (tissue) investigation should be done in any case of a lesion that arouses the suspicion of melanoma," recommended Seltenhammer.

Future Austrian studies focus on the genes responsible for melanoma development and metastasis, and prognostic and diagnostic marker systems for melanoma. "A simple blood sample should deliver significant answers," said Seltenhammer. "Moreover, therapy solutions on an immunological basis are going to be developed."
 
As the owner of a grey gelding with a pea sized lump under his dock (I presume a melanoma) I'm also interested in anything about the subject.

Here's a link to an article that I've found interesting because its quite detailed and also talks about possible cures (tagamet). http://www.miravalandalusians.com/garbosa/melanoma.htm I've kept the link in my favourites in case my horse's lump starts to change or grow.

Hope you find it useful.
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Ha ha - you've found the only article I could find on EVJ, too.
Although the abstract I read was a bit less helpful than yours above
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- I've just been doing my own % calculations!
I suppose the positive info is that none of the horses were adversely affected, even when they were considered to have Stage 4 melanomas on a Scale of 0 - 5.
It has to be blood line specific though - as virtually all Lipizzaners are grey, and it says there is a 'strong genetic impact' in the article I read.
It would be interesting to know the incidence of melanomas in grey horses of breeds other than the Camargue and Lipizzaners mentioned (both predominantly grey).
I wonder if the incidence is lower in grey horses from, say, TB breeds or others where the majority of horses are not grey coloured?
Fascinating stuff - find me some more!
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Just found a larger scale, although superficial study;

Melanomas in horses with light-colored fur - frequency, distribution and lesions in carcasses * Article partially translated to English language.
The complete article is available only in Brazilian Portuguese.


VOLUME 73 - NUMBER 6: Clinical, Epidemiological, Laboratory and Therapeutic Investigation

Authorship
Gercio Luiz Bonesi
Ana Paula F. R. L. Bracarense
Lorivaldo Minelli


Abstract
BACKGROUND - Horses are considered to have a high melanoma incidence rate among domestic animals. Melanoma in horses are more frequently found in older animals, of white or greyfur, usually on perineum and tail base causing nodale outgrowth.
OBJECTIVES - To verify the melanoma frequency rates in horses of light fur (white, gray, and albinos) slaughtered inslaughterhouses; its distribution on horse bodies and macroscopic lesions in carcasses.
METHODS - A total of 2.982 gray and white adult horses ( over five years old) slaughtered in the state of Paraná were studied for the presence of melanomas. The study of their frequency, distribution and anatomic regions were performed in carcasses previously inspected at post-mortem examination.
RESULTS - The melanoma frequency rate found in carcasses were 70,5% both for male and female horses. Tumor sizes ranged from 0,1 to 10cm wide, firmh, dark color, single or disseminated, some of irregular shape. Main affected regions consisted of skeletal muscle, thoracic and pelvic cavity, lumbar and sacral vertebrae bones mainly. The nodules disseminated in the carcasses were evaluated by histopathotogical examinations and it was shown that they were melanomas suggesting presence of metastases.
CONCLUSIONS - Melanomas are observed frequently in carcasses of white hair or gray hair equine with lesions present in several tissues observed at post-mortem examination. Equine can provide relevant for study of the cellular biology of melanoma growth.

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I have a 12 yo grey mare and she already had a melanoma under her tail when I bought her as a 6 yo. My vet said to leave well alone and she's not developed anymore
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I think you'll find more in the science journals than I can offer but my 33 year old is grey and melanoma free (at least he was tonight - sod's law says one will have appeared by the morning!
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However (and you may already have the stats for this - if so my apologies) I was just musing as to whether skin colour was relevant? Are pink skinned greys more succeptible than black skinned ones?
 
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