International Conference and Expo on Dermatopathology and Skin Care
American University of Beirut Medical Center, Beirut
Title: Braf analysis on a spectrum of Melanocytic Neoplasms: An Epidemiological study across differing UV Regions
Biography: Ibrahim Khalifeh
Background: BRAF mutation has been linked to the development of melanocytic tumors in homogeneous Caucasian cohorts. The role of solar UV radiation (UVR) in BRAF mutation status is poorly understood. We studied the epidemiology of BRAF mutation across a spectrum of melanocytic neoplasms in populations with differing UVR rates.
Design: Extended testing for 9 mutation types was attempted in 600 melanocytic neoplasms including banal nevi (n=225), dysplastic nevi (n=113), primary (n=172) and metastatic melanomas (n=90). Specimens were collected from 4 countries with increasing UVR rates (kJ/m2/yr): Syria (N=45; UVR=93.5), Lebanon (N=225; UVR=110), Pakistan (N=122; UVR=128) and Saudi Arabia (N=208; UVR=139). UVR was estimated as 21-year averages from The National Center for Atmospheric Research database.
Results: Overall BRAF mutation rate was 49% (268/545) and differed significantly by geographic location [34 % Pakistan, 49% Lebanon, 67% Syria and 54% Saudi Arabia ( =0.001)], neoplasm type ( <0.001) and anatomic location ( <0.001) but not with age ( =0.07) and gender ( =1.0). V600E was the predominant type in 96.3% of the cases. Incidence of melanoma was significantly greater in BRAF negative (77.6%) vs. BRAF positive (27.6%) groups. For BRAF positive, less severe lesions were systematically more frequent ( P <0.001). Multivariate analysis indicated that BRAF mutation is predicted by neoplasm type, anatomic and geographic locations.
Conclusion: In our Near East cohort, BRAF mutation rates varied by geographic location but not based on UVR. BRAF positive status was associated with less severe lesions.