[Prognostic significance of invasion in glioblastoma]

Glioblastoma is the most common malignant CNS tumor, its surgical removal is hindered by the tumors invasive nature, while current anti-tumor therapies show limited effectiveness - mean overall survival is 16-24 months. Some patients show minimal response towards standard oncotherapy, however there are no routinely available prognostic and predictive markers in clinical practice to identify the background of mentioned differences in prognosis. This research aims to identify the prognostic significance of invasion-related extracellular (ECM) components.

Patient groups with different prognoses were created (OS: group A <16 months, group B > 16 months), and internationally recognized prognostic markers (IDH1 mutation and MGMT promoter hyper-methylation) were tested in the flash-frozen tumor samples. Furthermore, the mRNA levels of 46 invasion-related ECM molecules were measured.

Clinical data of the patients who have been operated on at the University of Debrecen Clinical Center Department of Neurosurgery and treated at the Department of Clinical Oncology showed no significant differences except for survival data (OS and PFS), and reoperation rate. All samples were IDH wild type. MGMT promoter hypermethylation rate showed significant differences (28.6% vs 68.8%). The expressional pattern of the invasion-related ECM molecules, i.e. the invasion spectrum also showed major differences, integrin β2, cadherin-12, FLT4/VEGFR-3 and versican molecules having signficantly different mRNA levels. The accuracy of the inivasion spectrum was tested by statistical classifier, 83.3% of the samples was sorted correctly, PPV was 0.93.

The difference found in the reoperation rate when comparing different prognostic groups aligns with literature data. MGMG promoter region methylation data in Hungarian samples has not been published yet, and further confirming current knowledge urges the implementation of MGMT promoter analysis in clinical practice. Studying the invasion spectrum provides extra information on tumors, as a prognostic marker it helps recognizing more aggressive tumors, and calls attention to the necessity of using anti-invasive agents in GBM therapies in the future.