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Abstract Background Epigenetic inactivation of O6‐methylguanine‐methyltransferase (MGMT) gene by methylation of its promoter is predictive of Temozolomid (TMZ) response in glioblastoma (GBM). MGMT is located on chromosome 10q26 and the loss of chromosome 10q is observed in 70% of GBMs. In this study, we assessed the hypothesis that the dual inactivation of MGMT, by hypermethylation of MGMT promoter and by loss the long arm of chromosome 10 (10q), may confer greater sensitivity to TMZ. Methods A total of 149 tumor samples from patients diagnosed with GBM based on the WHO 2016 classification were included in this retrospective study between November 2016 and December 2018. Methylation status of MGMT promoter was evaluated by pyrosequencing and status of chromosome 10q was assessed by array comparative genomic hybridization. Results Glioblastoma patients with chromosome 10q loss associated with hypermethylation of MGMT promoter had significantly longer overall survival (OS) (P = .0024) and progression‐free survival (PFS) (P = .031). Indeed, median OS of patients with dual inactivation of MGMT was 21.5 months compared to 12 months and 8.1 months for groups with single MGMT inactivation by hypermethylation and by 10q loss, respectively. The group with no MGMT inactivation had 9.5 months OS. Moreover, all long‐term survivors with persistent response to TMZ treatment (OS ≥ 30 months) displayed dual inactivation of MGMT. Conclusions Our data suggest that the molecular subgroup characterized by the dual inactivation of MGMT receives greater benefit from TMZ treatment. The results of our study may be of immediate clinical interest since chromosome 10q status and methylation of MGMT promoter are commonly determined in routine practice.

Abstract Introduction ALK and ROS1 rearrangements are molecular targets of several tyrosine kinase inhibitors. RNA‐sequencing approaches are regarded as the new standard for fusion gene detection, representing an alternative to standard immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) techniques. Patients and Methods We aimed to compare two recent amplicon‐based RNA‐sequencing techniques: FusionPlex® Alk Ret Ros1 v2 Kit (Archer®) with FHS‐003Z‐12—Human Lung Cancer Panel (Qiagen®) and assessed the accuracy of the data for therapy management. Thirty‐seven formalin‐fixed paraffin‐embedded non‐small cell carcinoma (NSCC) lesions initially explored by IHC and FISH were selected for RNA‐sequencing analysis. Results Qiagen® and Archer® kits produced similar results and correctly identified 85.1% (23/27) and 81.5% (22/27) of IHC/FISH ALK‐ and ROS1‐positive samples, respectively, and 100% (6/6) of the negative samples. With regard to the ambiguous IHC‐positive/FISH‐negative cases, RNA‐sequencing confirmed 75% (3/4) of the FISH conclusion. Although not statistically significant, patients with common EML4‐ALK variants presented shorter overall survival and progression‐free survival compared with patients harboring rare variants. Conclusion Our findings assessed the implementation of RNA‐sequencing approaches to explore ALK and ROS1 rearrangements from formalin‐fixed paraffin‐embedded samples. We highlighted the similarities between Qiagen® and Archer® kits in terms of handling time, cost, and outcomes. We confirmed the feasibility of molecular testing in routine organization and its possible use not only as an alternative for standard IHC and FISH techniques, but as a supplementary technique helping to classify discrepant cases.