Coat color genotypes and risk and severity of melanoma in gray quarter horses.
Abstract: Both graying and melanoma formation in horses have recently been linked to a duplication in the STX17 gene. This duplication, as well as a mutation in the ASIP gene that increases MC1R pathway signaling, affects melanoma risk and severity in gray horses. Objective: To determine if melanoma susceptibility in gray Quarter Horses (QH) is lower than gray horses from other breeds because of decreased MC1R signaling resulting from a high incidence of the MC1R chestnut coat color allele in the QH population. Methods: A total of 335 gray QH with and without dermal melanomas. Methods: Blood or hair root samples were collected from all horses for DNA extraction and genotyping for STX17, ASIP, and MC1R genotypes. Age, sex, and external melanoma presence and grade were recorded. The effect of age and genotype on melanoma presence and severity was evaluated by candidate gene association. Results: Melanoma prevalence (16%) and grade (0.35) in this QH cohort was lower than that reported in other breeds. Age was significantly associated with melanoma prevalence (P = 5.28 × 10(-11)) and severity (P = 2.2 × 10(-13)). No significant effect of MC1R genotype on melanoma prevalence or severity was identified. An effect of ASIP genotype on melanoma risk was not detected. Low STX17 homozygosity precluded evaluation of the gray allele effect. Conclusions: Melanoma prevalence and severity is lower in this population of gray QH than what is reported in other breeds. This could be because of the infrequent STX17 homozygosity, a mitigating effect of the MC1R mutation on ASIP potentiation of melanoma, other genes in the MC1R signaling pathway, or differences in breed genetic background.
Copyright © 2013 by the American College of Veterinary Internal Medicine.
Publication Date: 2013-07-22 PubMed ID: 23875712DOI: 10.1111/jvim.12133Google Scholar: Lookup
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- Journal Article
- Research Support
- N.I.H.
- Extramural
- Research Support
- Non-U.S. Gov't
Summary
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This study explores the genetic factors that influence the risk and severity of melanoma in gray Quarter Horses. Contrary to what was expected, the MC1R chestnut coat color gene, which is common in Quarter Horses, did not significantly impact melanoma prevalence or severity.
Introduction and Objectives
- The focus of this research is the incidence and severity of melanoma in gray Quarter Horses.
- Previous studies have found links between the STX17 gene duplication and graying and melanoma formation in horses.
- It had been hypothesized that gray Quarter Horses might have a lower melanoma susceptibility due to decreased MC1R signaling resulting from a higher incidence of the MC1R chestnut coat color allele in the Quarter Horse population. This study was conducted to examine whether this hypothesis is correct.
Methods
- 335 gray Quarter Horses, both with and without dermal melanomas, were included in this study.
- From each horse, blood or hair root samples were collected to extract DNA and genotype for STX17, ASIP, and MC1R genes.
- The effect of age and genotype on melanoma presence and severity was evaluated using candidate gene association.
Results
- This Quarter Horse group had a lower melanoma prevalence and grade compared to what has been reported in other horse breeds.
- The age of the horse was significantly associated with melanoma prevalence (P = 5.28 × 10(-11)) and severity (P = 2.2 × 10(-13)).
- No significant effect of the MC1R genotype on melanoma prevalence or severity was identified.
- An effect of the ASIP genotype on melanoma risk was not detected.
- Low STX17 homozygosity prevented the evaluation of the potential effect of the gray allele.
Conclusions
- According to the data, melanoma prevalence and severity are lower in this population of gray Quarter Horses than what is reported in other breeds.
- This could be due to either infrequent STX17 homozygosity, a mitigating effect of the MC1R mutation on ASIP potentiation of melanoma, other genes in the MC1R signaling pathway, or differences in breed genetic background.
Cite This Article
APA
Teixeira RB, Rendahl AK, Anderson SM, Mickelson JR, Sigler D, Buchanan BR, Coleman RJ, McCue ME.
(2013).
Coat color genotypes and risk and severity of melanoma in gray quarter horses.
J Vet Intern Med, 27(5), 1201-1208.
https://doi.org/10.1111/jvim.12133 Publication
Researcher Affiliations
- Veterinary Population Medicine, University of Minnesota, St Paul, MN.
MeSH Terms
- Agouti Signaling Protein / genetics
- Agouti Signaling Protein / metabolism
- Animals
- Female
- Gene Expression Regulation
- Genetic Predisposition to Disease
- Genotype
- Homozygote
- Horse Diseases / genetics
- Horses
- Male
- Melanoma / genetics
- Melanoma / veterinary
- Mutation
- Qa-SNARE Proteins / genetics
- Qa-SNARE Proteins / metabolism
- Receptor, Melanocortin, Type 1 / genetics
- Receptor, Melanocortin, Type 1 / metabolism
Grant Funding
- 1K08AR055713-01A2 / NIAMS NIH HHS
- P30 AR057220 / NIAMS NIH HHS
Citations
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- Labelle AL, Gemensky Metzler AM, McMullen RJ Jr, Wiggans KT, Labelle P, Hamor RE. Equine intraocular melanocytic neoplasia. Can Vet J 2024 Oct;65(10):1048-1054.
- Pimenta J, Prada J, Pires I, Cotovio M. The Impact of Excision Interval on Equine Melanoma Progression: Time Matters?. Animals (Basel) 2024 Apr 22;14(8).
- Mura MC, Carcangiu V, Cosso G, Columbano N, Sanna Passino E, Luridiana S. Discrepancies between Genetic and Visual Coat Color Assignment in Sarcidano Horse. Animals (Basel) 2024 Feb 6;14(4).
- Pimenta J, Pires I, Prada J, Cotovio M. E-Cadherin Immunostaining in Equine Melanocytic Tumors. Animals (Basel) 2023 Jul 6;13(13).
- Pimenta J, Prada J, Cotovio M. Equine Melanocytic Tumors: A Narrative Review. Animals (Basel) 2023 Jan 10;13(2).
- Yi Z, Gao Y, Yu F, Zhu Y, Liu H, Li J, Murua Escobar H. Interventions for treatment of cutaneous melanoma in horses: a structured literature review. Vet Res Commun 2023 Jun;47(2):347-360.
- Weber LA, Funtan A, Paschke R, Delarocque J, Kalbitz J, Meißner J, Feige K, Kietzmann M, Cavalleri JV. In vitro assessment of triterpenoids NVX-207 and betulinyl-bis-sulfamate as a topical treatment for equine skin cancer. PLoS One 2020;15(11):e0241448.
- Pigoli C, Gibelli LR, Caniatti M, Moretti L, Sironi G, Giudice C. Bleaching melanin in formalin-fixed and paraffin-embedded melanoma specimens using visible light: a pilot study. Eur J Histochem 2019 Oct 31;63(4).
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