Is 2,3,5-pyrroletricarboxylic acid in hair a better risk indicator for melanoma than traditional epidemiologic measures for skin phenotype?
This study aims to assess type of melanin as a risk indicator for skin tumors, in a sample of melanoma cases and controls within a larger multicenter study (Helios 2), held in Europe and South America in 2001-2002. In each case and control, the melanin content in hair was assessed by three methods: 1) the amount of 2,3,5-pyrroletricarboxylic acid (PTCA); 2) the absorbance ratio with ultraviolet spectroscopy; and 3) the spectra of near-infrared spectroscopy. Statistical analysis was performed in a Bayesian setting, defining priors for confounders and effect modifiers from the larger study data set. Subjects with values of PTCA of less than 85 ng/mg carried an increased risk (26 vs. seven discordant pairs: odds ratio = 4.4, 95% confidence interval: 1.52, 14.54), adjusted by hair color, eye color, and number of nevi (n = > or =40). The absorbance ratio showed a weaker and nonsignificant odds ratio of 1.5. After correction by misclassification, near-infrared spectroscopy was associated with an odds ratio of 2.3 (95% confidence interval: 1.36, 4.22). The amount of PTCA is thus a strong and independent risk indicator for melanoma. Incorporating PTCA determination into epidemiologic studies is therefore recommended.
Rosso
Stefano
S
Oncology Prevention Center, Piedmont Cancer Registry, Turin, Italy. stefano.rosso@cpo.it
Zanetti
Roberto
R
Sánchez
Maria José
MJ
Nieto
Adoración
A
Miranda
Ana
A
Mercier
Mariette
M
Loria
Dora
D
Østerlind
Anne
A
Greinert
Rüdiger
R
Chirlaque
Maria-Dolores
MD
Fabbrocini
Gabriella
G
Barbera
Cesare
C
Sancho-Garnier
Hélène
H
Lauria
Carmela
C
Balzi
Daniela
D
Zoccola
Marina
M
D000328:Adult; D000368:Aged; D001499:Bayes Theorem; D016022:Case-Control Studies; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008297:Male; D008543:Melanins / Q000032:analysis*; D008545:Melanoma / Q000209:etiology*; D008875:Middle Aged; D010641:Phenotype; D011758:Pyrroles / Q000032:analysis*; D012307:Risk Factors; D012878:Skin Neoplasms / Q000209:etiology*; D019265:Spectroscopy, Near-Infrared
D008543:Melanins; D011758:Pyrroles; C041877:eumelanin; C071226:pyrrole-2,3,5-tricarboxylic acid