MC1R, ASIP, and DNA repair in sporadic and familial melanoma in a Mediterranean population.
BACKGROUND
Melanoma risk factors include fair pigmentation, multiple nevi, low DNA repair capacity, and CDKN2A or CDK4 mutations. Variants of the melanocortin-1 receptor (MC1R) gene have been associated with fair pigmentation and melanoma risk, and a polymorphism of the Agouti Signaling Protein (ASIP) gene has been associated with dark pigmentation. We examined MC1R and ASIP genotypes in relation to phenotypic characteristics, sporadic and familial melanoma risk, and melanoma thickness as an indicator of disease progression in a Mediterranean population.


METHODS
We studied 267 melanoma patients and 382 control subjects from a case-control study and a family study in northeastern Italy. Host factors were assessed by physical examination, questionnaire, spectrophotometer, and minimal erythema dose measurement. MC1R was sequenced, ASIP was genotyped, and DNA repair capacity was measured by the host-cell reactivation assay. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression models. Effect modification of the association between MC1R and melanoma risk by phenotypic characteristics and DNA repair capacity was also assessed. All statistical tests were two-sided.


RESULTS
Carrying MC1R variant alleles was associated with a two- to fourfold increase in risk of both sporadic and familial melanoma compared with carrying wild-type MC1R, particularly in individuals carrying multiple variant alleles (OR = 3.9; 95% CI = 3.3 to 4.6). This association was stronger in individuals with fewer additional risk factors (those with dark skin or few nevi). MC1R variant allele carriers were also three to four times more likely than were non-carriers to have thick melanomas. The ASIP polymorphism was not associated with pigmentation, nevi, or melanoma risk.


CONCLUSIONS
MC1R was associated with melanoma risk and progression in a Mediterranean population, particularly in the absence of other strong risk factors, such as freckling or many nevi.
Landi
Maria Teresa
MT
Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD 20892-7236, USA. landim@mail.nih.gov
Kanetsky
Peter A
PA
Tsang
Shirley
S
Gold
Bert
B
Munroe
David
D
Rebbeck
Timothy
T
Swoyer
Jennifer
J
Ter-Minassian
Monica
M
Hedayati
Mohammad
M
Grossman
Lawrence
L
Goldstein
Alisa M
AM
Calista
Donato
D
Pfeiffer
Ruth M
RM
D000293:Adolescent; D000328:Adult; D000368:Aged; D054366:Agouti Signaling Protein; D016022:Case-Control Studies; D016001:Confidence Intervals; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D004260:DNA Repair; D018450:Disease Progression; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics*; D007558:Italy / Q000453:epidemiology; D008297:Male; D019083:Mediterranean Region / Q000453:epidemiology; D008545:Melanoma / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D008875:Middle Aged; D009506:Nevus / Q000150:complications; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D044102:Receptor, Melanocortin, Type 1 / Q000235:genetics*; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D012880:Skin Pigmentation; D014466:Ultraviolet Rays
D054366:Agouti Signaling Protein; D019941:Cyclin-Dependent Kinase Inhibitor p16; D036341:Intercellular Signaling Peptides and Proteins; D044102:Receptor, Melanocortin, Type 1