426P - Comparison of microRNA expression levels between initial and recurrent glioblastoma specimens

Date 30 September 2012
Event ESMO Congress 2012
Session Poster presentation II
Topics Central Nervous System Malignancies
Translational Research
Presenter Aysegül Ilhan-Mutlu
Authors A. Ilhan-Mutlu1, A. Wöhrer2, A.S. Berghoff3, G. Widhalm4, C. Marosi5, L. Wagner6, M. Preusser7
  • 1Department Of Oncology, Medical University of Vienna, 1090 - Vienna/AT
  • 2Institute For Neurology, Medical University of Vienna, 1090 - Vienna/AT
  • 3Institute Of Neurology, Medical University of Vienna, 1090 - Vienna/AT
  • 4Department Of Neurosurgery, Medical University of Vienna, 1090 - Vienna/AT
  • 5Medical University of Vienna, 1090 - Vienna/AT
  • 6Department Of Nephrology, Medical University of Vienna, 1090 - Vienna/AT
  • 7Department Of Medicine I, Medical University of Vienna, 1090 - Vienna/AT

Abstract

Background

Glioblastoma is the most frequent primary brain tumour in adults. Recent therapeutic advances increased patient's survival rates, but tumour recurrence inevitably occurs and is associated with dismal prognosis. The pathobiological mechanisms involved in glioblastoma recurrence are still mostly unclear. MicroRNAs are a recently identified class of small non protein encoding RNAs and tumour‐specific microRNA signatures have been proposed as novel indicators for tumour proliferation, aggressiveness, differentiation and metastases development for many cancer types. However, there are only few data on the involvement of microRNAs in therapy resistance and recurrence of glioblastoma.

Methods

We selected the following 7 microRNAs with potential relevance for glioblastoma pathobiology by means of a comprehensive literature search: microRNA196b, microRNA21, microRNA10b, microRNA181b, microRNA181c, microRNA221, microRNA222 and microRNA195. We further selected 17 primary glioblastoma patients, of whom formalin fixed and paraffin embedded tissue (FFPE) tumor tissue samples of the initial operation and a re-operation for tumor recurrence were available. Patients had received first line treatment consisting of postoperative combined radiochemotherapy with temozolomide (n = 15) or fotemustine and dacarbazine (n = 2). We analysed the expression of the 7 microRNAs in all 34 tumor tissue samples by RT-qPCR. Expression levels were correlated with each other and with clinical parameters.

Results

All microRNAs except microRNA196b showed detectable levels of expressions. Comparison of microRNA levels between first and second resections revealed no significant change. Cox regression analyses showed no significant association of microRNA expression levels in the tumor tissue with progression free survival times.

Conclusion

Expression levels of microRNA21, microRNA10b, microRNA181b, microRNA181c, microRNA221, microRNA222 and microRNA195 do not to differ significantly between initial and recurrent tumors and seem not to influence time to recurrence in primary glioblastoma.

Disclosure

All authors have declared no conflicts of interest.