Profiling of Somatic Mutations in Phaeochromocytoma and Paraganglioma by Targeted Next Generation Sequencing Analysis

At least 12 genes (FH, HIF2A, MAX, NF1, RET, SDHA, SDHB, SDHC, SDHD, SDHAF2, TMEM127,andVHL) have been implicated in inherited predisposition to phaeochromocytoma (PCC), paraganglioma (PGL), or head and neck paraganglioma (HNPGL) and a germline mutation may be detected in more than 30% of cases. Knowledge of somatic mutations contributing to PCC/PGL/HNPGL pathogenesis has received less attention though mutations inHRAS, HIF2A, NF1, RET,andVHLhave been reported. To further elucidate the role of somatic mutation in PCC/PGL/HNPGL tumourigenesis, we employed a next generation sequencing strategy to analyse “mutation hotspots” in 50 human cancer genes. Mutations were identified forHRAS(c.37G>C; p.G13R and c.182A>G; p.Q61R) in 7.1% (6/85); forBRAF(c.1799T>A; p.V600E) in 1.2% (1/85) of tumours; and forTP53(c.1010G>A; p.R337H) in 2.35% (2/85) of cases. Twenty-one tumours harboured mutations in inherited PCC/PGL/HNPGL genes and noHRAS, BRAF, orTP53mutations occurred in this group. Combining our data with previous reports ofHRASmutations in PCC/PGL we find that the mean frequency ofHRAS/BRAFmutations in sporadic PCC/PGL is 8.9% (24/269) and in PCC/PGL with an inherited gene mutation 0% (0/148) suggesting thatHRAS/BRAFmutations and inherited PCC/PGL genes mutations might be mutually exclusive. We report the first evidence forBRAFmutations in the pathogenesis of PCC/PGL/HNPGL.