1111P - Genotyping melanoma in Colombia

Date 28 September 2014
Event ESMO 2014
Session Poster Display session
Topics Melanoma and other Skin Tumours
Pathology/Molecular Biology
Translational Research
Presenter Hernan Carranza
Citation Annals of Oncology (2014) 25 (suppl_4): iv374-iv393. 10.1093/annonc/mdu344
Authors H. Carranza1, A.F. Cardona2, C.A. Vargas3, P. Archila4, J. Otero5, L. Bernal3, O. Arrieta6, J. Rodríguez4, J. Insuasty7, D. Lopera8, A. Jimenez Orozco9, M. Lema10, I. Durango11, A. Yepes12, G. Rojas-Uribe13, R. Duarte14, L.R. Gomez Wolf9, D. Torres4
  • 1Clinical And Translational Oncology Group, Fundacion Sta Fe de Bogota, 100101000 - Bogota/CO
  • 2Clinical And Translational Oncology Group, Fundacion Sta Fe de Bogota Instituto de Oncologia, Bogota/CO
  • 3Clinical And Translational Oncology Group, Fundacion Sta Fe de Bogota, Bogota/CO
  • 4Pathology, Foundation for Clinical and Applied Cancer Research - FICMAC, Bogota/CO
  • 5Clinical And Translational Oncology Group, Fundacion Sta Fe de BogotaInstituto de Oncologia, CO- - Bogota/CO
  • 6Thoracic Oncology Unit And Experimental Oncology Laboratory, National Cancer Institute (INCan), 14080 - DF/MX
  • 7Medicina Interna, Universidad Industrial de Santander, Bucaramanga/CO
  • 8Clinical Oncology, Oncologos del Occidente S.A., Pereira/CO
  • 9Clinical Oncology, Clinica Las Americas Instituto de Cancerologia, CO- - Medellin/CO
  • 10Clinica Soma - Oncologia Clinica, Clinica SOMA, Medellin/CO
  • 11Clinical Oncology, Hospital Pablo Tobón Uribe, Medellin/CO
  • 12Clinical Oncology, Hospital Pablo Tobon Uribe, CO- - Medellin/CO
  • 13Clinical Oncology, Oncologos del Occidente S.A., CO- - Pereira/CO
  • 14Internal Medicine, Fundacion Sanitas Universitaria, CO- - Bogota/CO

Abstract

Aim

Melanoma has high clonal heterogeneity which follows a geographical pattern. The advent of therapy involving BRAF-specific inhibitors has enabled many efforts at exploring these neoplasias' genotype around the world, documenting V600E and V600K alterations in about 50% of affected patients born in the USA, Western Europe and Australia. Few studies have evaluated the presence of alterations in the BRAF and KIT in the Hispanic population, finding a frequency between 39 and 77%, and 0%, respectively.

Methods

216 patients were explored for BRAF (V600E/V600K), NRAS (exons 1 and 2) and cKIT (exons 9, 11, 13 and 17) mutations using sequencing and RT-PCR (COBAS) techniques, following confirmation of histology and micro-dissection. Several outcomes were recorded in 98 cases.

Results

median age was 55.4 years old on average (SD ± 13.8), 62% were older than 50 when diagnosed and 112 cases (52%) were female. When ascertaining the origin of the tumors 30% of the melanomas were found in skin which had been chronically exposed to sunlight, 43.1% could not be typed, 13.9% were acral-lentiginous melanomas, 7.9% were primary mucosal melanomas and 0.5% were uveal tumours. Tumour representation in paraffin-embedded tissue was good (80%), the site from which the sample was taken was usually the skin (43%), lymph nodes (24%), soft tissues (7%) and the lungs (6.5%). Tumour stage was greater than III in 75% and unknown in the rest. BRAF mutation frequency was 32.5% (67/206), 8.4% (11/131) for cKIT and 6.9% (9/131) for NRAS. KI67 was greater than 20% in 57% (101/175); this finding was greater in patients suffering lesions in chronically-exposed skin (p = 0.054) and in those carrying a BRAF mutation (p = 0.038). Median follow-up was 14.5-mo (95%CI 4.0-42.0) and overall survival was 18-mo (95%CI 16.8-19.1). Survival was modified by Clark (p = 0.036) but not by different genotypes.

Conclusions

The mutational profile of Colombian melanoma patients reported in this study differ with that described previously in other Western countries, especially for BRAF; however, such findings did agree with greater prevalence of mucosal and acral-lentiginous lesions.

Disclosure

All authors have declared no conflicts of interest.