Effect of ultraviolet radiation on melanogenesis in four different types of cultured bovine ocular pigmented cells

Sahm, Monika; Loeffler, Karin U.; Seifert, Péter; Spitznas, Manfred

doi:10.1007/s004170100271

Cited by 8 publications

(6 citation statements)

References 20 publications

(25 reference statements)

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“…Currently, no evidence suggests an adaptive pigmentary response to sun exposure in the choroid or other pigmentary epithelia of the eye. 39 Speculatively, too, ocular sun exposure may be greater per unit of time in outdoor work than in other outdoor exposures because choice about the direction of gaze in relation to the position of the sun may be less in occupational settings.…”

Section: Discussionmentioning

confidence: 99%

Sun exposure predicts risk of ocular melanoma in Australia

Vajdic¹,

Kricker

Giblin

et al. 2002

Intl Journal of Cancer

129

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Previous studies examining sun exposure and ocular melanoma have produced inconsistent results. We investigated this association in a population-based case-control study in Australia. Cases (n ‫؍‬ 290) aged 18 -79 years were diagnosed between January 1996 and July 1998. Controls (n ‫؍‬ 893) were randomly selected from the electoral rolls and frequencymatched to cases by age, sex and state. A self-administered questionnaire and a telephone interview measured sun exposure on weekdays and weekends at 10, 20, 30 and 40 years of age and over the whole of life for specific jobs and recreations. Multivariate logistic regression models of ocular melanoma and sun exposure contained age, sex, region of birth, eye color and measures of ocular and cutaneous sun sensitivity as covariates. Choroid and ciliary body melanoma (n ‫؍‬ 246) was positively associated with time outdoors on weekdays and, less persuasively, total time outdoors but not ambient solar irradiance. Odds ratios increased with increasing exposure to OR 1.8 (95% confidence interval 1.1-2.8) for the highest quarter of sun exposure on weekdays up to 40 years of age for men and women together. The strongest positive associations were for total exposure up to 40 years of age, lifetime occupational exposure and total exposure at about 20 years of age in men; all had odds ratios between 2 and 3 in the highest exposure categories. There was inconclusive evidence for an association between sun exposure and iris (n ‫؍‬ 25) or conjunctival (n ‫؍‬ 19) melanomas. Sun exposure is an independent risk factor for choroidal and ciliary body melanoma in Australia. © 2002 Wiley-Liss, Inc. Key words: ocular melanoma; aetiology; sun exposure; UV radiation; AustraliaThe estimated risks of ocular melanoma associated with personal sun exposure, ambient solar irradiance and use of protective wear have been inconsistent both within and between case-control studies. [1][2][3][4][5][6][7][8][9] However, positive associations with factors less prone to measurement error, such as indicators of sun sensitivity 10 and exposure to artificial sources of UV radiation (e.g., welding arcs and sunlamps), 4,9 suggest a positive association with solar radiation.Possible explanations for past inconclusive results include nonpopulation-based ascertainment of cases and controls, use of qualitative or crude quantitative sun-exposure measures and inadequate control of potential confounding factors, particularly sun sensitivity. Moreover, previous studies collected little or no sun-exposure data for the early years of life. If sun exposure is a risk factor for melanoma of the choroid and ciliary body, the commonest subsites of ocular melanoma, the aetiologically relevant exposure period is probably from birth to the early 20s, when there is some transmission of UV radiation by the crystalline lens to these posterior ocular sites. 11,12 Finally, the unique exposure characteristics of the eye necessitate accounting for personal protective behaviors and environmental factors in estimating ocular sun exposure...

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Section: Discussionmentioning

confidence: 99%

Sun exposure predicts risk of ocular melanoma in Australia

Vajdic¹,

Kricker

Giblin

et al. 2002

Intl Journal of Cancer

129

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“…Although the melanocytes of the uvea, conjunctiva and skin have a common embryologic origin [24], there are important differences between them. Unlike cutaneous melanocytes, there is no evidence that incident ultraviolet radiation initiates melanogenesis in ocular melanocytes [25]. It is also uncertain whether uveal melanocytes produce melanin in vivo during adulthood [26]; ocular melanosomes are relatively inactive and remain within the melanocyte, whereas epidermal melanocytes continuously synthesize melanosomes and transfer them to keratinocytes [27].…”

Section: Discussionmentioning

confidence: 99%

Ocular melanoma is not associated with CDKN2A or MC1R variants — a population-based study

Vajdic¹,

Kricker²,

Duffy³

et al. 2003

Melanoma Research

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Germline variants in the melanocortin 1 receptor gene (MC1R) and the p16 gene (CDKN2A) are associated with an increased risk of cutaneous melanoma. The frequency of these germline variants was examined in a populationbased, incident series of 62 ocular melanoma cases and ethnicity-matched population controls. In both cases and controls, 59% of individuals carried at least one MC1R variant and there were no significant differences in the frequency of any of the five most common variants of MC1R. We also found no significant differences between cases and controls in the frequency of any of the four most common variants of CDKN2A, and no melanoma case carried a deleterious germline CDKN2A mutation. Our findings argue against an important predisposing effect of the MC1R and CDKN2A genes for ocular melanoma.

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“…Firstly, there is no evidence that ultraviolet light initiates melanogenesis in uveal melanomas (Sahm et al, 2001). Secondly, it is unclear whether uveal melanocytes continue to synthesise melanin in adulthood (Hu et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

Role of MC1R variants in uveal melanoma

et al. 2003

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Variants of the melanocortin-1 receptor (MC1R) gene have been linked to sun-sensitive skin types and hair colour, and may independently play a role in susceptibility to cutaneous melanoma. To assess the role of MC1R variants in uveal melanoma, we have analysed a cohort of 350 patients for the changes within the major region of the gene displaying sequence variation. Eight variants were detected -V60L, D84E, V92M, R151C, I155T, R160W, R163Q and D294H -63% of these patients being hetero-or homozygous for at least one variant. Standard melanoma risk factor data were available on 119 of the patients. MC1R variants were significantly associated with hair colour (P ¼ 0.03) but not skin or eye colour. The frequency of the variants detected in the 350 patients was comparable with those in the general population, and comparison of the cumulative tumour distribution by age at diagnosis in carriers and noncarriers provided no evidence that MC1R variants confer an increased risk of uveal melanoma. We interpret the data as indicating that MC1R variants do not appear to be major determinants of susceptibility to uveal melanoma.

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Effect of ultraviolet radiation on melanogenesis in four different types of cultured bovine ocular pigmented cells

Abstract: In vitro, there was no convincing evidence of ultraviolet radiation-induced melanogenesis in ocular pigmented cells. Thus, it seems that ultraviolet radiation is a selection factor: more densely pigmented cells survive the treatment better than less pigmented cells.

Cited by 8 publications

References 20 publications

Sun exposure predicts risk of ocular melanoma in Australia

Sun exposure predicts risk of ocular melanoma in Australia

Ocular melanoma is not associated with CDKN2A or MC1R variants — a population-based study

Role of MC1R variants in uveal melanoma

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