Competing Interests Statement RMS, TAC and LGTM are inventors on a provisional patent application (62/569,053) filed by MSK, relating to the use of TMB in cancer immunotherapy.MDH, NAR and TAC are inventors on a PCT patent application (PCT/US2015/062208) filed by MSK, relating to the use of TMB in lung cancer immunotherapy.MSK and the inventors may receive a share of commercialization revenue from license agreements relating to these patent applications. CHL received research funding from Eisai, BMS, Exelixis, Pfizer, Calithera and consulting fees from Exelixis and Eisai. ANS has received research support from Bristol Myers Squibb, Immunocore, Astra-Zeneca, Xcovery and serves on the advisory board for Bristol Myers Squibb, Immunocore, Castle Biosciences; he also receives royalties from UpToDate. MDH receives research funding from Bristol-Myers Squibb; is paid consultant to Merck

Glioblastoma is the most common primary malignant brain tumor in adults and associated with poor survival. The Ivy Foundation Early Phase Clinical Trials Consortium conducted a randomized, multi-institution clinical trial to evaluate immune responses and survival following neoadjuvant and/or adjuvant therapy with pembrolizumab in 35 patients with recurrent, surgically resectable glioblastoma. Patients who were randomized to receive neoadjuvant pembrolizumab, with continued adjuvant therapy following surgery, had significantly extended overall survival compared to patients that were randomized to receive adjuvant, post-surgical PD-1 blockade alone. Neoadjuvant PD-1 blockade was associated with upregulation of T cell and interferon-γ-related gene expression, but downregulation of cell cycle-related gene expression within the tumor, which was not seen in patients that received adjuvant therapy alone. Focal induction of programmed death-ligand 1 (PD-L1) in the tumor microenvironment, enhanced clonal expansion of T cells, decreased PD-1 expression on peripheral blood T cells, and a decreasing monocytic population was observed more frequently in the neoadjuvant group than patients treated only in the adjuvant setting. These findings suggest that the neoadjuvant administration of PD-1 blockade enhances the local and systemic anti-tumor immune response and may represent a more efficacious approach to the treatment of this uniformly lethal brain tumor.

Evolving interest in meningioma, the most common primary brain tumor, has refined contemporary management of these tumors. Problematic, however, is the paucity of prospective clinical trials that provide an evidence-based algorithm for managing meningioma. The current review summarizes the published literature regarding the treatment of newly diagnosed and recurrent meningioma, with an emphasis on outcomes stratified by World Health Organization (WHO) tumor grade. In particular this review focuses on patient outcomes following treatment (either adjuvant or at recurrence) with surgery or radiation therapy inclusive of radiosurgery and fractionated irradiation. Phase II trials for patients with meningioma have recently completed accrual within the Radiation Therapy Oncology Group (RTOG) and the European Organization for Research and Treatment of Cancer (EORTC) consortia, and phase III studies are being developed. However, at present, there are no completed prospective, randomized trials assessing the role of either surgery or radiotherapy. Successful completion of future studies will require a multidisciplinary effort, dissemination of the current knowledge base, improved implementation of WHO grading criteria, standardization of response criteria and other outcome endpoints, and concerted efforts to address weaknesses in present treatment paradigms, particularly for patients with progressive or recurrent low grade meningioma, or with high-grade meningioma. In parallel efforts, Response Assessment in Neuro-Oncology (RANO) subcommittees are developing a manuscript on systemic therapies for meningioma, and a separate article proposing standardized endpoint and response criteria for meningioma.

Bruton tyrosine kinase (BTK) links the B-cell antigen receptor (BCR) and Toll-like receptors with Nuclear factor kappa B (NF-κB). The role of BTK in primary CNS lymphoma (PCNSL) is unknown. We performed a Phase 1 clinical trial with ibrutinib, the first-in-class BTK inhibitor, for patients with relapsed or refractory CNS Lymphoma. Clinical responses to ibrutinib occurred in 10/13 (77%) PCNSL patients, including five complete responses. The only PCNSL with complete ibrutinib resistance harbored a mutation within the coiled-coil domain of Caspase Recruitment Domain Family Member 11, a known ibrutinib resistance mechanism. Incomplete tumor responses were associated with mutations in the B-Cell Antigen Receptor-associated protein CD79B. CD79B-mutant PCNSLs showed enrichment of mammalian target of rapamycin (mTOR)-related gene sets and increased staining with Phosphatidylinositol 3-kinase (PI3K)/mTOR activation markers. Inhibition of the PI3K-isoforms p110α/p110δ or mTOR synergized with ibrutinib to induce cell death in CD79B-mutant PCNSL cells.