New Insights on the Genetics of Pheochromocytoma and Paraganglioma and Its Clinical Implications.

Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are rare neuroendocrine tumors that arise from chromaffin cells. PHEOs arise from the adrenal medulla, whereas PGLs arise from the neural crest localized outside the adrenal gland. Approximately 40% of all cases of PPGLs (pheochromocytomas/paragangliomas) are associated with germline mutations and 30-40% display somatic driver mutations. The mutations associated with PPGLs can be classified into three groups. The pseudohypoxic group or cluster I includes the following genes: SDHA , SDHB , SDHC , SDHD , SDHAF2 , FH , VHL , IDH1/2 , MHD2 , EGLN1/2 and HIF2/EPAS ; the kinase group or cluster II includes RET , NF1 , TMEM127 , MAX and HRAS ; and the Wnt signaling group or cluster III includes CSDE1 and MAML3 . Underlying mutations can help understand the clinical presentation, overall prognosis and surveillance follow-up. Here we are discussing the new genetic insights of PPGLs.