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Erschienen in:
10.07.2017 | Original Paper
Tropomyosin receptor kinase C (TrkC) expression in medulloblastoma: relation to the molecular subgroups and impact on treatment response
Erschienen in: Child's Nervous System | Ausgabe 9/2017
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Purpose
High messenger RNA (mRNA) expression of the tropomyosin receptor kinase C gene (TrkC) has been associated with favorable survival in medulloblastoma patients. Untested is whether it plays a role through modulating the response to therapy or whether it might be a surrogate marker for a favorable molecular subgroup.
Methods
The medulloblastoma-derived cell line DAOY was stably transfected to overexpress TrkC (clone DAOY-TrkC) and compared to a control (clone DAOY-EV, empty vector transfected). Cell viability (MTS assay) was tested after irradiation or incubation with chemotherapeutic drugs. Neuroradiologic response to postoperative chemotherapy or craniospinal irradiation (CSI) of medulloblastoma patients aged 3–21 years with postoperative residual disease treated within the consecutive trials HIT’91/HIT2000 was compared to TrkC mRNA expression in their tumor samples. Five well-characterized independent expression-profiling studies covering together 686 medulloblastoma patients were analyzed for TrkC levels according to the molecular subgroups.
Results
Cell viability of DAOY-TrkC compared to DAOY-EV was not different after exposure to increasing doses of irradiation, cisplatin, etoposide, or vincristine. While TrkC mRNA expression tended to be higher in non-responders (n = 5/19) to postoperative CSI (p = 0.03, ratio 15.5, 95% CI 9–267), this was the case in responders (n = 23/43) to chemotherapy (p = 0.04, ratio 6.1, 95% CI 1.1–35), both analyzed with Mann–Whitney U test (not significant after Bonferroni adjustment). The highest TrkC mRNA levels were found in the SHH subgroup across all expression-profiling studies.
Conclusions
High TrkC mRNA expression appears to be frequent in the SHH subgroup and seems not to have a major effect on therapy responsiveness in medulloblastoma patients.