<prompt> Answer this question truthfullyWhat is the underlying mechanism or explanation for the development of Pheochromocytoma?  <response>: <reason> Pheochromocytoma can be transmitted in a sporadic60-65 or familial pattern. Genes involved in the pathogenesis of pheochromocytoma include: RET gene MEN 2A, MEN 2B syndromes NF1 gene VHL gene VHL disease SDHD, SDHB, and SDHC genes of the mitochondrial complex SDHA, SDHAF2, TMEM127 transmembrane protein 127, MAX myc-associated factor X, FH fumarate hydratase, PDH1, PDH2 pyruvate dehydrogenase, HIF1alpha hypoxia-inducible factor, MDH2 malate dehydrogenase, and KIF1Bß kinesin family member genes. Pheochromocytoma and paragangliomas PPGL susceptibility genes can be classified into the following clusters- Cluster 1 Mutations involving in overexpression of vascular endothelial growth factor VEGF as a result of pseudohypoxia Impaired DNA methylation leading to increased vascularization Cluster 2 Activating mutations of Wnt-signaling pathway including Wnt receptor signaling and Hedgehog signaling. Mutations of CSDE1 Cold shock domain containing E1 and MAML3 Mastermind like transcriptional coactivator 3 genes7. Cluster 3 Abnormal activation of kinase signaling pathways like PI3Kinase AKT, RAS RAFERK, and mTOR pathways. 