title: The clinical utility of circulating neuroendocrine gene transcript analysis in well-differentiated paragangliomas and pheochromocytomas.
abstract: BACKGROUND
  Paragangliomas and pheochromocytomas (PPGLs) exhibit variable malignancy, which is difficult to determine by histopathology, amine measurements or tissue genetic analyses.
  
  
  OBJECTIVE
  To evaluate whether a 51-neuroendocrine gene blood analysis has clinical utility as a diagnostic and prognostic marker.
  
  
  METHODS
  Prospective cohort study. Well-differentiated PPGLs (n = 32), metastatic (n = 4); SDHx mutation (n = 25); 12 biochemically active, Lanreotide treated (n = 4). Nine patients had multiple sampling. Age- and gender-matched controls and GEP-NETs (comparators).
  
  
  METHODS
  Circulating neuroendocrine tumor mRNA measured (qPCR) with multianalyte algorithmic analysis. Metabolic, epigenomic and proliferative genes as well as somatostatin receptor expression were assessed (averaged, normalized gene expression: mean ± s.e.m.). Amines were measured by HPLC and chromogranin A by ELISA. Analyses (2-tailed): Fisher's test, non-parametric (Mann-Whitney), receiver-operator curve (ROC) and multivariate analysis (MVA). All data are presented as mean ± s.e.m.
  
  
  RESULTS
  PPGL were NETest positive (100%). All exhibited higher scores than controls (55 ± 5% vs 8 ± 1%, P = 0.0001), similar to GEP-NETs (47 ± 5%). ROC analysis area under curve was 0.98 for differentiating PPGLs/controls (cut-off for normal: 26.7%). Mutation status was not directly linked to NETest. Genetic and molecular clustering was associated (P < 0.04) with NETest scores. Metastatic (80 ± 9%) and multicentric (64 ± 9%) disease had significantly (P < 0.04) higher scores than localized disease (43 ± 7%). Progressive disease (PD) had the highest scores (86 ± 2%) vs stable (SD, 41 ± 2%) (P < 0.0001). The area under the curve for PD from SD was 0.93 (cut-off for PD: 53%). Proliferation, epigenetic and somatostatin receptor gene expression was elevated (P < 0.03) in PD. Metabolic gene expression was decreased in SDHx mutations. Repeat NETest measurements defined clinical status in the 9 patients (6 SD and 3 PD). Amine measurement was non-informative. Multivariate analysis identified NETest >53% as an independent prognostic factor.
  
  
  CONCLUSIONS
  Circulating NET transcript analysis is positive (100% diagnostic) in well-differentiated PCC/PGL, scores were elevated in progressive disease irrespective of mutation or biochemical activity and elevated levels were prognostic.
authors.affiliation: Institute of CardiologyWarsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Pęczkowska
authors.affiliation: University of Warmia and MazuryThe Faculty of Medical Sciences, Olsztyn, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Cwikla
authors.affiliation: Wren LaboratoriesBranford, Connecticut, USA mark@wrenlaboratories.com imodlin@optonline.net.
authors.forename: M
authors.initials: M
authors.lastname: Kidd
authors.affiliation: Medical University of GdanskGdansk, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Lewczuk
authors.affiliation: Maria Skłodowska-Curie Memorial Cancer CenterWarsaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Kolasinska-Ćwikła
authors.affiliation: Institute of CardiologyWarsaw, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Niec
authors.affiliation: Institute of CardiologyWarsaw, Poland.
authors.forename: I
authors.initials: I
authors.lastname: Michałowska
authors.affiliation: Institute of CardiologyWarsaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Prejbisz
authors.affiliation: Institute of CardiologyWarsaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Januszewicz
authors.affiliation: Wren LaboratoriesBranford, Connecticut, USA.
authors.forename: J
authors.initials: J
authors.lastname: Chiarelli
authors.affiliation: Memorial Sloan Kettering Cancer CenterNew York, USA.
authors.forename: L
authors.initials: L
authors.lastname: Bodei
authors.affiliation: Yale University School of MedicineNew Haven, Connecticut, USA mark@wrenlaboratories.com imodlin@optonline.net.
authors.forename: I
authors.initials: I
authors.lastname: Modlin
mesh_terms: D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics; D002648:Child; D005260:Female; D006801:Humans; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000235:genetics; D010235:Paraganglioma / Q000235:genetics*; D010673:Pheochromocytoma / Q000235:genetics*; D011247:Pregnancy; D011446:Prospective Studies; D017481:Receptors, Somatostatin / Q000378:metabolism; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D017481:Receptors, Somatostatin