title: Elevated telomerase activity, c-MYC-, and hTERT mRNA expression: association with tumour progression in malignant lipomatous tumours.
abstract: The role of telomerase activity in tumour progression of liposarcomas is not well understood. Therefore, we investigated 72 liposarcomas of different histological subtypes for an association between telomeric lengths and telomerase activity, and assessed the association between the catalytic subunit human telomerase reverse transcriptase (hTERT) and its activator c-MYC. Telomeric repeat fragment lengths were determined using radioactive DNA-fingerprint analysis with the telomere-specific probe (TTAGGG)(3), whereas telomerase activity was ascertained using the non-radioactive TRAP-assay. To evaluate the expression of hTERT and c-MYC, we applied real-time RT-PCR using a LightCycler. Eight tumours were investigated by microdissection. The MIB1-proliferation index and hTERT and c-MYC protein expression were determined immunohistochemically. Genetic alterations showed a high degree of tumour specificity. Highly malignant myxoid/round cell liposarcomas showed the longest telomeres, the strongest telomerase activity, and the highest hTERT and c-MYC expression levels compared with the pure myxoid variants (p < 0.001), which are of low malignancy. Pleomorphic liposarcoma was characterized by zero or low hTERT and c-MYC expression and telomerase activity, but long telomeres, underlining their different pathogenetic pathway. Elevated gene expression was accompanied by protein immunopositivity. MIB1-proliferation index did not correlate with other molecular markers. We conclude that hTERT and c-MYC expression are associated with telomerase activity in liposarcomas. Elevated hTERT and c-MYC expression as well as high telomerase activity play a role in the tumour progression of this sarcoma type. Nevertheless, each histological subtype of liposarcomas is defined by a specific molecular pattern. Telomerase activation is the most common pathway in liposarcomas maintaining telomeric length.
authors.affiliation: Department of Pathology, Otto-von-Guericke University, Magdeburg, Germany. Regine-Schneider-Stock@magdeburg.de
authors.forename: Regine
authors.initials: R
authors.lastname: Schneider-Stock
authors.forename: Carsten
authors.initials: C
authors.lastname: Boltze
authors.forename: Viola
authors.initials: V
authors.lastname: Jäger
authors.forename: Jörg
authors.initials: J
authors.lastname: Epplen
authors.forename: Olfert
authors.initials: O
authors.lastname: Landt
authors.forename: Brigitte
authors.initials: B
authors.lastname: Peters
authors.forename: Janusz
authors.initials: J
authors.lastname: Rys
authors.forename: Albert
authors.initials: A
authors.lastname: Roessner
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D002455:Cell Division; D016172:DNA Fingerprinting / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics; D004268:DNA-Binding Proteins; D018450:Disease Progression; D015870:Gene Expression; D006801:Humans; D008080:Liposarcoma / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D018208:Liposarcoma, Myxoid / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000648:ultrastructure
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D019098:Telomerase