gms | German Medical Science

Objective: Preoperative magnetic resonance imaging (MRI) is not only the gold standard for diagnosis of an intrinsic brain tumor such as a Glioblastoma multiforme (GBM), but does also guide surgical therapy. Within a given study population, however, the MRI appearance of the individual GBM vary widely which might have a potential impact on clinical outcome and survival. Thus the objective of this study was to determine the impact of 10 different single nucleotide polymorphisms (SNPs) on various volumetric parameters in patients harboring a GBM.

Method: We prospectively analyzed 20 steroid-naïve adult patients who had been treated for newly diagnosed GBM. The volumetry was performed using MRI with the help of a semi-automated quantitative software measuring contrast enhancing tumor volume including necrosis, central necrosis alone and peritumoral edema (PTE). We calculated ratios between the tumor volume and edema (ETR), respectively necrosis (NTR). SNP analysis was done using genomic DNA extracted from peripheral blood genotyped via PCR and sequencing.

Results: There was a strong correlation between tumor volume and PTE (p < 0,001), necrosis (p < 0,001) and NTR (p = 0,003). Age and sex had no influence on volumetric data. The Aquaporin 4 -131G>A SNP had a significant influence on the ETR (p = 0,042) by decreasing the measured edema compared with the tumor volume. The Interleukin 8 -251A>T SNP was significantly correlated with an increased tumor (p = 0,048), PTE (p = 0,033) and necrosis volume (p = 0,028).

Conclusions: We identified two SNPs with a distinct impact on pretreatment tumor characteristics, presenting a potential explanation for the individual diversity of GBM appearance on MRI and influence on survival.