Genotype and tumor locus determine expression profile of pseudohypoxic pheochromocytomas and paragangliomas

Neoplasia. 2013 Apr;15(4):435-47. doi: 10.1593/neo.122132.

Abstract

Pheochromocytomas (PHEOs) and paragangliomas (PGLs) related to mutations in the mitochondrial succinate dehydrogenase (SDH) subunits A, B, C, and D, SDH complex assembly factor 2, and the von Hippel-Lindau (VHL) genes share a pseudohypoxic expression profile. However, genotype-specific differences in expression have been emerging. Development of effective new therapies for distinctive manifestations, e.g., a high rate of malignancy in SDHB- or predisposition to multifocal PGLs in SDHD patients, mandates improved stratification. To identify mutation/location-related characteristics among pseudohypoxic PHEOs/PGLs, we used comprehensive microarray profiling (SDHB: n = 18, SDHD-abdominal/thoracic (AT): n = 6, SDHD-head/neck (HN): n = 8, VHL: n = 13). To avoid location-specific bias, typical adrenal medulla genes were derived from matched normal medullas and cortices (n = 8) for data normalization. Unsupervised analysis identified two dominant clusters, separating SDHB and SDHD-AT PHEOs/PGLs (cluster A) from VHL PHEOs and SDHD-HN PGLs (cluster B). Supervised analysis yielded 6937 highly predictive genes (misclassification error rate of 0.175). Enrichment analysis revealed that energy metabolism and inflammation/fibrosis-related genes were most pronouncedly changed in clusters A and B, respectively. A minimum subset of 40 classifiers was validated by quantitative real-time polymerase chain reaction (quantitative real-time polymerase chain reaction vs. microarray: r = 0.87). Expression of several individual classifiers was identified as characteristic for VHL and SDHD-HN PHEOs and PGLs. In the present study, we show for the first time that SDHD-HN PGLs share more features with VHL PHEOs than with SDHD-AT PGLs. The presented data suggest novel subclassification of pseudohypoxic PHEOs/PGLs and implies cluster-specific pathogenic mechanisms and treatment strategies.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adrenal Gland Neoplasms / genetics*
  • Adrenal Gland Neoplasms / metabolism
  • Adult
  • Aged
  • Cell Hypoxia
  • Child
  • Child, Preschool
  • Cluster Analysis
  • Female
  • Genotype
  • Humans
  • Liver Cirrhosis / genetics
  • Male
  • Middle Aged
  • Mutation
  • Oligonucleotide Array Sequence Analysis
  • Oxidative Phosphorylation
  • Paraganglioma / genetics
  • Paraganglioma / metabolism
  • Pheochromocytoma / genetics*
  • Pheochromocytoma / metabolism
  • Principal Component Analysis
  • Succinate Dehydrogenase / genetics
  • Succinate Dehydrogenase / metabolism
  • Transcriptome*
  • Von Hippel-Lindau Tumor Suppressor Protein / genetics
  • Von Hippel-Lindau Tumor Suppressor Protein / metabolism
  • Young Adult

Substances

  • SDHD protein, human
  • SDHB protein, human
  • Succinate Dehydrogenase
  • Von Hippel-Lindau Tumor Suppressor Protein
  • VHL protein, human