title: MicroRNA expression profiling in benign (sporadic and hereditary) and recurring adrenal pheochromocytomas.
abstract: MicroRNAs are involved in the pathogenesis of several tumors, however, there have been no data on microRNA expression in pheochromocytomas to date. The objective of our study was to perform microRNA expression profiling in sporadic and hereditary benign, and recurring adrenomedullary tumors. Furthermore, the applicability of formalin-fixed paraffin-embedded tissue samples for the analysis of microRNA expression in pheochromocytomas was examined. MicroRNA expression data of three matched frozen and formalin-fixed paraffin-embedded samples were correlated. A total of 21 formalin-fixed paraffin-embedded samples (sporadic benign, multiple endocrine neoplasia 2, von Hippel-Lindau disease, sporadic recurring) were subjected to microRNA expression profiling using microarrays. MicroRNAs with significant differences in expression were validated and sample sizes were extended including tumors from neurofibromatosis type 1 patients by real-time quantitative reverse-transcription PCR (n=33). MicroRNA target prediction was carried out by TargetScan and MicroCosm Targets. Pathway analysis of targets was performed by Ingenuity Pathway Analysis and DIANA mirPath. Furthermore, microRNA expression profiles of a malignant pheochromocytoma and a pair of primary and recurrent tumors were studied by TaqMan Human MicroRNA Cards. MicroRNA expression correlated well between frozen and formalin-fixed paraffin-embedded samples (70-92%). Microarray analysis revealed 16 significantly differentially expressed microRNAs. Five of these were validated by real-time RT-PCR. miR-139-3p, miR-541 and miR-765 were significantly differentially expressed between sporadic benign and von Hippel-Lindau-related pheochromocytomas. Significantly higher expression of miR-885-5p and miR-1225-3p was found in multiple endocrine neoplasia type 2 and sporadic recurring pheochromocytomas, respectively. Pathway analysis revealed the possible involvement of Notch- and G-protein-coupled receptor signaling in tumor recurrence. MicroRNA expression profiles in the primary recurrent and recurring malignant comparisons have been similar. In conclusion, we have proved that formalin-fixed paraffin-embedded samples can be used for the analysis of microRNA expression in pheochromocytomas. MicroRNA expression patterns differ between various sporadic, hereditary and recurring tumors and miR-1225-3p may be useful for identifying recurring pheochromocytomas.
authors.affiliation: Faculty of Medicine, 2nd Department of Medicine, Semmelweis University, Budapest, Hungary.
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Tömböl
authors.forename: Katalin
authors.initials: K
authors.lastname: Eder
authors.forename: Attila
authors.initials: A
authors.lastname: Kovács
authors.forename: Peter M
authors.initials: PM
authors.lastname: Szabó
authors.forename: Janina
authors.initials: J
authors.lastname: Kulka
authors.forename: István
authors.initials: I
authors.lastname: Likó
authors.forename: Attila
authors.initials: A
authors.lastname: Zalatnai
authors.forename: Gergely
authors.initials: G
authors.lastname: Rácz
authors.forename: Miklós
authors.initials: M
authors.lastname: Tóth
authors.forename: Attila
authors.initials: A
authors.lastname: Patócs
authors.forename: András
authors.initials: A
authors.lastname: Falus
authors.forename: Károly
authors.initials: K
authors.lastname: Rácz
authors.forename: Peter
authors.initials: P
authors.lastname: Igaz
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000235:genetics*; D000328:Adult; D016000:Cluster Analysis; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000032:analysis / Q000235:genetics*; D008875:Middle Aged; D018813:Multiple Endocrine Neoplasia Type 2a / Q000150:complications / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010673:Pheochromocytoma / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D006623:von Hippel-Lindau Disease / Q000150:complications / Q000235:genetics
chemical_list: D035683:MicroRNAs