Updates on the genetics and the clinical impacts on phaeochromocytoma and paraganglioma in the new era

Abstract

Genetic mutations of phaeochromocytoma (PCC) and paraganglioma (PGL) are mainly classified into two major clusters. Cluster 1 mutations are involved with the pseudo hypoxic pathway and comprised of PHD2, VHL, SDHx, IDH, HIF2A, MDH2 and FH mutated PCC/PGL. Cluster 2 mutations are associated with abnormal activation of kinase signalling pathways and included mutations of RET, NF1, KIF1Bβ, MAX and TMEM127. In addition, VHL, SDHx (cluster 1 genes) and RET, NF1 (cluster 2 genes) germline mutations are involved in the neuronal precursor cell pathway in the pathogeneses of PCC/PGL. Also, GDNF, H-ras, K-ras, GNAS, CDKN2A (p16), p53, BAP1, BRCA1&2, ATRX and KMT2D mutations have roles in the development of PCC/PGLs. Overall, known genetic mutations account for the pathogenesis of approximately 60% of PCC/PGLs. Genetic mutations, pathological parameters and biochemical markers are used for better prediction of the outcome of patients with this group of tumours. Immunohistochemistry and gene sequencing can ensure a more effective detection, prediction of malignant potential and treatment of PCC/PCLs.

Keywords: Immunohistochemistry; Mutations; Paraganglioma; Phaeochromocytoma; Sequencing.