1121P - Association of MCC C. *5077A > G, PTCH1 G.79755C > T and PTCH1 G.79456C > T polymorphisms with inherited risk of cutaneous melanoma

Date 01 October 2012
Event ESMO Congress 2012
Session Poster presentation III
Topics Melanoma and other Skin Tumours
Translational Research
Presenter Guilherme Augusto Nogueira
Authors G.A.S. Nogueira1, G.J. Lourenco1, C. Oliveira2, J.A. Rinck Jr.1, E.F.D. Costa3, A.M. Moraes1, C.S.P. Lima1
  • 1Clinical Medical, University of Campinas, 13083888 - Campinas/BR
  • 2Department Of Internal Medicine, University of Campinas, 13083888 - Campinas/BR
  • 3Clinical Medical Departament, University of Campinas, 13083888 - Campinas/BR

Abstract

Background

Recently we found that SNPs alter the oropharynx carcinoma risk in tumor suppressor MCC c.*5077A > G, PTCH1 g.79755C > T, and PTCH1 g.79456C > T. This study was conducted using high-resolution large-scale DNA microarray genotyping (5.0 SNP array, Affymetrix ®), and the quantities and functions of the proteins encoded by distinct alleles of the polymorphisms are being examined by our research group. Objective: We aimed to verify whether the different genotypes of polymorphisms in MCC c.*5077A > G, PTCH1 g.79755C > T, and PTCH1 g.79456C > T alter the CM susceptibility.

Materials and methods

Genomic DNA of 149 CM patients and 153 controls was analyzed by TaqMan genotyping (Applied Biosystems®). Statistical significance of differences between groups was calculated by using chi-square (?2) and Fisher's exact tests. Power analysis (PA) was used to verify the effect of sample size on the results obtained in the study.

Results

Samples from patients with MC and controls were in Hardy-Weinberg equilibrium for MCC and PTCH1 loci. Similar frequencies of MCC and PTCH1 genotypes were observed in patients and controls. Individuals with distinct isolated genotypes of the genes were under similar risks for CM. The frequencies of the combined genotypes MCC 5077AA + PTCH1 79755CC (90.4% versus 72.3%, P= 0.004; PA: 99.0%), MCC 5077AA + PTCH1 79456CC (89 0% versus 71.6%, P= 0.008; PA: 98.0%), and MCC 5077AA + PTCH1 79755CC + PTCH1 79456CC (91.3% versus 76.1%, P= 0.004; PA: 99.0%) were higher in patients than in controls. Individuals with these genotypes were at 4.44 (CI95%: 1.68 – 13.17), 3.60 (CI95%: 1.45 – .87), and 4.70 (CI95%: 1.75 – 14.63)-fold increased risks for CM than others, respectively.

Conclusion

Our results suggest that combined MCC and PTCH1 polymorphisms are an important inherited risk factor for CM. We believe that healthy carriers with these genotypes deserve recommendations for protecting their skin from the harmful effects of UV rays to prevent tumor disease and periodic follow-up with the dermatologist for early tumor diagnosis. Financial support: State of São Paulo Research Foundation (FAPESP) and Research and Project Financing (FINEP)

Disclosure

All authors have declared no conflicts of interest.