Background:It has recently been reported by several sources that original (i.e., present in vivo) glioma cell phenotypes or genotypes cannot be maintained in vitro. For example, glioblastoma cell lines presenting EGFR amplification cannot be established.Methods and results:IDH1 sequencing and loss of heterozygosity analysis was performed for 15 surgery samples of astrocytoma and early and late passages of cells derived from those and for 11 archival samples. We were not able to culture tumour cells presenting IDH1 mutations originating from currently proceeded 10 tumours; the same results were observed in 7 samples of archival material.Conclusion:The IDH1 mutation is expected to be almost mutually exclusive with EGFR amplification, so glioma cells with IDH1 mutations seem to represent a new group of tumour cells, which cannot be readily analysed in vitro because of their elimination. The reasons for this intriguing phenomenon should be investigated since its understanding can help to define a new therapeutic approach based on simulating in vivo conditions, responsible for tumour cells elimination in vitro. Moreover, a new model for culturing glioma cells in vitro should be designed since the current one does not provide conditions corresponding to in vivo growth.

O6-methylguanine-methyltransferase (MGMT) promoter methylation status has prognostic and, in the subpopulation of elderly patients, predictive value in newly diagnosed glioblastoma. Therefore, knowledge of the MGMT promoter methylation status is important for clinical decision-making. So far, MGMT testing has been limited by the lack of a robust test with sufficiently high analytical performance. Recently, one of several available pyrosequencing protocols has been shown to be an accurate and robust method for MGMT testing in an intra- and interlaboratory ring trial. However, some uncertainties remain with regard to methodological issues, cut-off definitions, and optimal use in the clinical setting. In this article, we highlight and discuss several of these open questions. The main unresolved issues are the definition of the most relevant CpG sites to analyze for clinical purposes and the determination of a cut-off value for dichotomization of quantitative MGMT pyrosequencing results into “MGMT methylated” and “MGMT unmethylated” patient subgroups as a basis for further treatment decisions.

Cell line analysis is an important element of cancer research. Despite the progress in glioblastoma cell culturing, the cells isolated from the majority of specimens cannot be propagated infinitely in vitro. The aim of this study was to identify the processes responsible for the stabilization failure. Therefore, we analyzed 56 primary GB cultures, 7 of which were stabilized. Our results indicate that senescence is primarily responsible for the glioblastoma cell line stabilization failure, while mitotic catastrophe and apoptosis play a minor role. Moreover, a new technical approach allowed for a more profound analysis of the senescent cells in primary cultures, including the distinction between tumor and normal cells. In addition, we observed that glioblastoma cells in primary cultures have a varied potential to undergo spontaneous in vitro senescence, which is often higher than that of the normal cells infiltrating the tumor. Thus, this is the first report of GB cells in primary cell cultures (including both monolayer and spheroid conditions) rapidly and spontaneously becoming senescent. Intriguingly, our data also suggest that nearly half of GB cell lines have a combination of TP53 mutation and CDKN2A homozygous deletion, which are considered as mutually exclusive in glioblastoma. Moreover, recognition of the mechanisms of senescence and mitotic catastrophe in glioblastoma cells may be a step towards a potential new therapeutic approach.

Glioblastoma is a highly aggressive tumour of the central nervous system, characterised by poor prognosis irrespective of the applied treatment. The aim of our study was to analyse whether the molecular markers of glioblastoma (i.e. TP53 and IDH1 mutations, CDKN2A deletion, EGFR amplification, chromosome 7 polysomy and EGFRvIII expression) could be associated with distinct prognosis and/or response to the therapy. Moreover, we describe a method which allows for a reliable, as well as time- and cost-effective, screening for EGFR amplification and chromosome 7 polysomy with quantitative Real-Time PCR at DNA level. In the clinical data, only the patient’s age had prognostic significance (continuous: HR = 1.04; p<0.01). At the molecular level, EGFRvIII expression was associated with a better prognosis (HR = 0.37; p = 0.04). Intriguingly, EGFR amplification was associated with a worse outcome in younger patients (HR = 3.75; p<0.01) and in patients treated with radiotherapy (HR = 2.71; p = 0.03). We did not observe any difference between the patients with the amplification treated with radiotherapy and the patients without such a treatment. Next, EGFR amplification was related to a better prognosis in combination with the homozygous CDKN2A deletion (HR = 0.12; p = 0.01), but to a poorer prognosis in combination with chromosome 7 polysomy (HR = 14.88; p = 0.01). Importantly, the results emphasise the necessity to distinguish both mechanisms of the increased EGFR gene copy number (amplification and polysomy). To conclude, although the data presented here require validation in different groups of patients, they strongly advocate the consideration of the patient’s tumour molecular characteristics in the selection of the therapy.

Background: Immune checkpoint inhibitors (ICIs) are standard of care in advanced non-small cell lung cancer (NSCLC), however their status in patients with poor performance status (PS) is poorly defined. We aimed to evaluate the efficacy and safety of ICIs in NSCLC patients with PS ≥ 2. Methods: We conducted a systematic review and meta-analysis of interventional and observational studies, which reported efficacy and safety data on ICIs in PS ≥ 2 comparing to PS ≤ 1 NSCLC patients. Efficacy endpoints included: Objective Response Rate (ORR), Disease-Control Rate (DCR), Overall Survival (OS), Progression-Free Survival (PFS). Safety endpoint was the incidence of severe (grade≥3) Adverse Events (AE). Random-effects model was applied for meta-analysis. Heterogeneity was assessed using I 2 . The review is registered on PROS-PERO (CRD42020162668). Findings: Sixty-seven studies (n = 26,442 patients) were included. In PS ≥ 2 vs. PS ≤ 1 patients, the pooled odds ratios were: for ORR 0.46 (95 %CI: 0.39− 0.54, I 2 :0 %); for DCR 0.39 (95 %CI: 0.33− 0.48, I 2 :50 %) and for AEs 1.12 (95 %CI: 0.84-1.48, I 2 :39 %). The pooled hazard ratio for PFS was 2.17 (95 %CI: 1.96-2.39, I 2 :65 %) and for OS was 2.76 (95 %CI: 2.43-3.14, I 2 :76 %). The safety profile was comparable regardless of the PS status. Interpretation: Patients with impaired PS status are, on average, twice less likely to achieve a response when exposed to ICIs when compared with representative PS ≤ 1 population. For lung cancer patients treated with ICIs, the impaired PS is not only prognostic, but also predictive for response, while the safety profile is not affected. Prospective randomized studies are indispensable to determine whether poor PS patients derive benefit from ICIs.