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Iris pigmented lesions as a marker of cutaneous melanoma risk: an Australian case–control study
Author(s) -
Laino A.M.,
Berry E.G.,
Jagirdar K.,
Lee K.J.,
Duffy D.L.,
Soyer H.P.,
Sturm R.A.
Publication year - 2018
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/bjd.16323
Subject(s) - eye color , iris (biosensor) , medicine , melanoma , dermatology , population , case control study , odds ratio , pathology , biology , genetics , computer security , environmental health , cancer research , gene , computer science , biometrics
Summary Background Iris naevi and iris freckles have a frequency of 4% and 50% in the European population, respectively. They are associated with dysplastic naevi, but few studies have examined their link to cutaneous melanoma. Objectives To assess whether iris pigmented lesions are a predictive indicator for cutaneous melanoma. Methods This is a melanoma case–control study of 1254 European‐background Australians. Sun exposure and melanoma history, a saliva sample for DNA analysis and eye photographs taken with a digital camera were collected from 1117 participants. Iris images were assessed by up to four trained observers for the number of iris pigmented lesions. The data were analysed for correlations between iris pigmented lesions and melanoma history. Results Case participants over the age of 40 had similar numbers of iris pigmented lesions to age matched controls (mean 5·7 vs. 5·2, P = 0·02), but in younger case and control participants there was a greater difference (mean 3·96 vs. 2·19, P = 0·004). A logistic regression adjusted for age, sex, skin, hair and eye colour, skin freckling and naevus count found that the presence of three or more iris pigmented lesions increases the melanoma risk 1·45‐fold [95% confidence interval ( CI ) 1·07–1·95]. HERC 2 / OCA 2 rs12913832 and IRF 4 rs12203592 influenced both eye colour and the number of iris pigmented lesions. On the HERC 2 / OCA 2 A/A and A/G genotype background there was an increasing proportion of blue eye colour when carrying the IRF 4 T allele ( P = 3 × 10 −4 ) and a higher number of iris pigmented lesions with the IRF 4 T/T homozygote ( P = 3 × 10 −9 ). Conclusions Iris pigmented lesion count provides additional predictive information for melanoma risk above that from conventional risk factors.