RNA expression patterns in serum microvesicles from patients with glioblastoma multiforme and controls

Microvesicle RNA from serum from patients with de-novo primary glioblastoma multiforme (N = 9) and normal controls (N = 7) were analyzed by microarray analysis. Samples were collected according to protocols approved by the Institutional Review Board. Differential expressions were validated by qRT-PCR in a separate set of samples (N = 10 in both groups).Expression profiles of microvesicle RNA correctly separated individuals in two groups by unsupervised clustering. The most significant differences pertained to down-regulated genes (121 genes > 2-fold down) in the glioblastoma multiforme patient microvesicle RNA, validated by qRT-PCR on several genes. Overall, yields of microvesicle RNA from patients was higher than from normal controls, but the additional RNA was primarily of size < 500 nt. Gene ontology of the down-regulated genes indicated these are coding for ribosomal proteins and genes related to ribosome production.Serum microvesicle RNA from patients with glioblastoma multiforme has significantly down-regulated levels of RNAs coding for ribosome production, compared to normal healthy controls, but a large overabundance of RNA of unknown origin with size < 500 nt.Cancer molecular diagnostics is becoming increasingly important with the accumulating knowledge of the molecular mechanisms underlying various types of cancers and the implications for treatment option selection and prognosis. For patients with glioblastoma multiforme (GBM), treatment planning currently takes into account radiographic imaging, which documents volume and location of disease [1], and in some cases mutational analysis [2], methylation status of genomic DNA with particular emphasis on the DNA repair gene for methyl guanidine methyl transferase (MGMT [3]) and gene expression patterns of the tumour, which allows the broad categorization of tumours that are histologically similar into molecular subtypes [4]. To date most molecular studies have utilized primary explant cultures or frozen, form