1. ¹Department of Oncology, University Hospital, SE 901 85 Umeå, Sweden
2. ²Research Group for Chemometrics, Department of Chemistry, Umeå University, SE 901 87 Umeå, Sweden
3. ³Department of Neurosurgery, University Hospital, SE 901 85, Umeå, Sweden

Correspondence: Professor AT Bergenheim, E-mail: tommy.bergenheim@neuro.umu.se

Revised 24 April 2006; Accepted 26 April 2006; Published online 30 May 2006.

Abstract

Radiotherapy is one of the mainstays of glioblastoma (GBM) treatment. This study aims to investigate and characterise differences in protein expression patterns in brain tumour tissue following radiotherapy, in order to gain a more detailed understanding of the biological effects. Rat BT4C glioma cells were implanted into the brain of two groups of 12 BDIX-rats. One group received radiotherapy (12 Gy single fraction). Protein expression in normal and tumour brain tissue, collected at four different time points after irradiation, were analysed using surface enhanced laser desorption/ionisation – time of flight – mass spectrometry (SELDI-TOF-MS). Mass spectrometric data were analysed by principal component analysis (PCA) and partial least squares (PLS). Using these multivariate projection methods we detected differences between tumours and normal tissue, radiation treatment-induced changes and temporal effects. 77 peaks whose intensity significantly changed after radiotherapy were discovered. The prompt changes in the protein expression following irradiation might help elucidate biological events induced by radiation. The combination of SELDI-TOF-MS with PCA and PLS seems to be well suited for studying these changes. In a further perspective these findings may prove to be useful in the development of new GBM treatment approaches.