The combination of ionizing radiation and peripheral vaccination produces long-term survival of mice bearing established invasive GL261 gliomas

Radiation drives tertiary lymphoid structures to reshape TME for synergized antitumour immunity

Radiotherapy (RT) plays a key role in the tumour microenvironment (TME), impacting the immune response via cellular and humoral immunity. RT can induce local immunity to modify the TME. It can stimulate dendritic cell maturation and T-cell infiltration. Moreover, B cells, macrophages and other immune cells may also be affected. Tertiary lymphoid structure (TLS) is a unique structure within the TME and a class of aggregates containing T cells, B cells and other immune cells. The maturation of TLS is determined by the presence of mature dendritic cells, the density of TLS is determined by the number of immune cells. TLS maturation and density both affect the antitumour immune response in the TME. This review summarized the recent research on the impact and the role of RT on TLS, including the changes of TLS components and formation conditions and the mechanism of how RT affects TLS and transforms the TME. RT may promote TLS maturation and density to modify the TME regarding enhanced antitumour immunity.

Strategies for treating the cold tumors of cholangiocarcinoma: core concepts and future directions

Cholangiocarcinoma (CCA) is a rare type of digestive tract cancer originating from the epithelial cells of the liver and biliary tract. Current treatment modalities for CCA, such as chemotherapy and radiation therapy, have demonstrated limited efficacy in enhancing survival rates. Despite the revolutionary potential of immunotherapy in cancer management, its application in CCA remains restricted due to the minimal infiltration of immune cells in these tumors, rendering them cold and unresponsive to immune checkpoint inhibitors (ICIs). Cancer cells within cold tumors deploy various mechanisms for evading immune attack, thus impeding clinical management. Recently, combination immunotherapy has become increasingly essential to comprehend the mechanisms underlying cold tumors to enhance a deficient antitumor immune response. Therefore, a thorough understanding of the knowledge on the combination immunotherapy of cold CCA is imperative to leverage the benefits of immunotherapy in treating patients. Moreover, gut microbiota plays an essential role in the immunotherapeutic responses in CCA. In this review, we summarize the current concepts of immunotherapy in CCA and clarify the intricate dynamics within the tumor immune microenvironment (TIME) of CCA. We also delve into the evasion mechanisms employed by CCA tumors against the anti-tumor immune responses. The context of combination immunotherapies in igniting cold tumors of CCA and the critical function of gut microbiota in prompting immune responses have also been annotated. Furthermore, we have proposed future directions in the realm of CCA immunotherapy, aiming to improve the clinical prognosis of CCA patients.

Hypofractionated stereotactic radiotherapy for brain metastases in lung cancer patients: dose‒response effect and toxicity

BACKGROUND

Lung cancer is a common cause of brain metastases, approximately 40% of patients with lung cancer will develop brain metastases at some point during their disease. Hypofractionated stereotactic radiotherapy (HSRT) has been demonstrated to be effective in controlling limited brain metastases. However, there is still no conclusive on the optimal segmentation of HSRT. The aim of our study was to explore the correlation between the HSRT dosage and its treatment effect and toxicity.

METHODS

A retrospective analysis was conducted on patients with non-small cell lung cancer (NSCLC) brain metastasis at Hangzhou Cancer Hospital from 1 January 2019 to 1 January 2021. The number of brain metastases did not exceed 10 in all patients and the number of fractions of HSRT was 5. The prescription dose ranges from 25 to 40 Gy. The Kaplan-Meier method was used for estimation of the localised intracranial control rate (iLC). Adverse radiation effects (AREs) were evaluated according to CTCAE 5.0. This study was approved by the Institutional Ethics Review Board of the Hangzhou Cancer Hospital (#73/HZCH-2022).

RESULTS

Forty eligible patients with a total of 70 brain metastases were included in this study. The 1-year iLC was 76% and 89% in the prescribed dose ≤ 30 Gy and > 30 Gy group, respectively (P < 0.05). For patients treated with HSRT combined with targeted therapy, immunotherapy and chemotherapy, the 1-year iLC was 89%, 100%, and 45%, respectively. No significant associations were observed between the number, maximum diameter, location, and type of pathology of brain metastases. The rate of all-grade AREs was 33%. Two patients who received a total dose of 40 Gy developed grade 3 headache, the rest of the AREs were grade 1-2.

CONCLUSIONS

Increasing the prescription dose of HSRT improves treatment effect but may also exacerbate the side effects. Systemic therapy might impact the iLC rate, and individualized treatment regimens need to be developed.

Evaluation of the anticarcinogenic effects of Rutin on brain tissue in mice with Ehrlich ascites carcinoma by micro-computed tomography and histological methods

BACKGROUND

Studies for new treatment strategies on cancer continue, and new searches continue in the diagnosis and evaluation of cancer. This study examined the possible anticarcinogenic effect of Rutin on the brain tissues of male mice with Ehrlich ascites carcinoma (EAC).

MATERIAL AND METHODS

We used micro-computed tomography (micro-CT) and histologically Hematoxylin&Eosin (H&E) staining methods for evaluation.

RESULTS

In the evaluation results, we saw a significant decrease in the brain volume of the tumor group to the control group. The difference in volume between the Rutin treatment group and the control group was not significant. In the brain tissues of the tumor group, numerous degenerated neurons characterized by pericellular/perivascular space expansion, cell swelling, or expansion were detected in the cortex and hippocampus regions. We showed a reduction in the damage rate in the Rutin treated group.

CONCLUSION

As a result, Rutin was found to have an anticarcinogenic effect. In addition to the classical histological evaluation, we used a newer method, micro-CT, in our study. We believe that this study has important results both in terms of its originality and adding new information to the literature.

Molecular determinants of immunogenic cell death elicited by radiation therapy

Cancer cells undergoing immunogenic cell death (ICD) can initiate adaptive immune responses against dead cell-associated antigens, provided that (1) said antigens are not perfectly covered by central tolerance (antigenicity), (2) cell death occurs along with the emission of immunostimulatory cytokines and damage-associated molecular patterns (DAMPs) that actively engage immune effector mechanisms (adjuvanticity), and (3) the microenvironment of dying cells is permissive for the initiation of adaptive immunity. Finally, ICD-driven immune responses can only operate and exert cytotoxic effector functions if the microenvironment of target cancer cells enables immune cell infiltration and activity. Multiple forms of radiation, including non-ionizing (ultraviolet) and ionizing radiation, elicit bona fide ICD as they increase both the antigenicity and adjuvanticity of dying cancer cells. Here, we review the molecular determinants of ICD as elicited by radiation as we critically discuss strategies to reinforce the immunogenicity of cancer cells succumbing to clinically available radiation strategies.

Targeting MHC-I molecules for cancer: function, mechanism, and therapeutic prospects

The molecules of Major histocompatibility class I (MHC-I) load peptides and present them on the cell surface, which provided the immune system with the signal to detect and eliminate the infected or cancerous cells. In the context of cancer, owing to the crucial immune-regulatory roles played by MHC-I molecules, the abnormal modulation of MHC-I expression and function could be hijacked by tumor cells to escape the immune surveillance and attack, thereby promoting tumoral progression and impairing the efficacy of cancer immunotherapy. Here we reviewed and discussed the recent studies and discoveries related to the MHC-I molecules and their multidirectional functions in the development of cancer, mainly focusing on the interactions between MHC-I and the multiple participators in the tumor microenvironment and highlighting the significance of targeting MHC-I for optimizing the efficacy of cancer immunotherapy and a deeper understanding of the dynamic nature and functioning mechanism of MHC-I in cancer.

Clinical outcomes and timing on the combination of focal radiation therapy and immunotherapy for the treatment of brain metastases

Introduction

Radiotherapy is one of the standard treatments for brain metastases (BM). Over the past years, the introduction of immunotherapy as routine treatment for solid tumors has forced investigators to review and evaluate how it would interact with radiation. Radiation and Immunotherapy have shown a synergic effect activating the host's immune system and enhancing treatment response. The combinatory effect on BM is currently under investigation.

Methods

Data published on Pubmed to determine toxicity, survival, treatment characteristics and timing on the combination of radiotherapy and immunotherapy for the treatment of BM has been reviewed.

Results

Mostly retrospective reviews report an improvement of intracranial progression free survival (iPFS) when combining radioimmunotherapy for BM patients. Two systematic reviews and meta-analysis and one phase II prospective trial also report a benefit on iPFS without an increase of toxicity. Among the published literature, the definition of concurrency is heterogeneous, being one month or even narrowed intervals correlated to better clinical outcomes. Toxicity due to concurrent radioimmunotherapy, specifically symptomatic radionecrosis, is also directly analyzed and reported to be low, similar to the toxicity rates secondary to stereotactic radiosurgery alone.

Conclusion

Radiation combined with immunotherapy has shown in predominantly retrospective reviews a synergic effect on the treatment of BM. The concurrent combination of radioimmunotherapy is a feasible therapeutic strategy and seems to improve clinical outcomes, especially iPFS, when delivered within <30 days. Larger prospective and randomized studies are needed to establish reliable outcomes, best delivery strategies and toxicity profile.

Immunologically relevant effects of radiation therapy on the tumor microenvironment

Focal radiation therapy (RT) has been successfully employed to clinically manage multiple types of cancer for more than a century. Besides being preferentially cytotoxic for malignant cells over their nontransformed counterparts, RT elicits numerous microenvironmental alterations that appear to factor into its therapeutic efficacy. Here, we briefly discuss immunostimulatory and immunosuppressive microenvironmental changes elicited by RT and their impact on tumor recognition by the host immune system.

Optimizing the synergy between stereotactic radiosurgery and immunotherapy for brain metastases

Solid tumors metastasizing to the brain are a frequent occurrence with an estimated incidence of approximately 30% of all cases. The longstanding conventional standard of care comprises surgical resection and whole-brain radiotherapy (WBRT); however, this approach is associated with limited long-term survival and local control outcomes. Consequently, stereotactic radiosurgery (SRS) has emerged as a potential alternative approach. The primary aim of SRS has been to improve long-term control rates. Nevertheless, rare observations of abscopal or out-of-field effects have sparked interest in the potential to elicit antitumor immunity via the administration of high-dose radiation. The blood-brain barrier (BBB) has traditionally posed a significant challenge to the efficacy of systemic therapy in managing intracranial metastasis. However, recent insights into the immune-brain interface and the development of immunotherapeutic agents have shown promise in preclinical and early-phase clinical trials. Researchers have investigated combining immunotherapy with SRS to enhance treatment outcomes in patients with brain metastasis. The combination approach aims to optimize long-term control and overall survival (OS) outcomes by leveraging the synergistic effects of both therapies. Initial findings have been encouraging in the management of various intracranial metastases, while further studies are required to determine the optimal order of administration, radiation doses, and fractionation regimens that have the potential for the best tumor response. Currently, several clinical trials are underway to assess the safety and efficacy of administering immunotherapeutic agents concurrently or consecutively with SRS. In this review, we conduct a comprehensive analysis of the advantages and drawbacks of integrating immunotherapy into conventional SRS protocols for the treatment of intracranial metastasis.

Emerging evidence for adapting radiotherapy to immunotherapy

Immunotherapy has revolutionized the clinical management of many malignancies but is infrequently associated with durable objective responses when used as a standalone treatment approach, calling for the development of combinatorial regimens with superior efficacy and acceptable toxicity. Radiotherapy, the most commonly used oncological treatment, has attracted considerable attention as a combination partner for immunotherapy owing to its well-known and predictable safety profile, widespread clinical availability, and potential for immunostimulatory effects. However, numerous randomized clinical trials investigating radiotherapy-immunotherapy combinations have failed to demonstrate a therapeutic benefit compared with either modality alone. Such a lack of interaction might reflect suboptimal study design, choice of end points and/or administration of radiotherapy according to standard schedules and target volumes. Indeed, radiotherapy has empirically evolved towards radiation doses and fields that enable maximal cancer cell killing with manageable toxicity to healthy tissues, without much consideration of potential radiation-induced immunostimulatory effects. Herein, we propose the concept that successful radiotherapy-immunotherapy combinations might require modifications of standard radiotherapy regimens and target volumes to optimally sustain immune fitness and enhance the antitumour immune response in support of meaningful clinical benefits.

On target methods to induce abscopal phenomenon for Off-Target effects: From happenstance to happenings

Although the "abscopal phenomenon" has been described several decades ago, this phenomenon lately has been obtaining momentous traction with the dawn of immune-based therapies. There has been increased cross talk among radiation oncologists, oncologists and immunologists and consequently a surge in the number of prospective clinical trials. This must be coupled with translation work from these clinical trials to aid in eventual identification of patients who may benefit. Abscopal effects may be induced by local and systemic methods, conventional radiotherapy, particle radiation, radionucleotide methods, cryoablation and brachytherapy. These approaches have all been reported to be stimulate abscopal effect. Immune induction by immune checkpoint therapy, immune adjuvants, cellular therapy including CAR and NK cell therapies may generate systemic abscopal response. With increasing recognition of this effect, there remains a lot of work to explore the modalities of inducing abscopal responses and ultimate prediction or prognostication on stratifying who may benefit. Ultimately, there is an urgent need for prospective studies and data to tease apart which one of these modalities can be applied to the appropriate candidate, to the appropriate cancer at the appropriate setting. This review seeks to elucidate readers on the different modalities of radiation, systemic therapies and other techniques rarely explored to potentiate the abscopal effect from a mere coincidence to a finite occurrence.

Concurrent immunotherapy and re-irradiation utilizing stereotactic body radiotherapy for recurrent high-grade gliomas

BACKGROUND

Clinical trials evaluating immune checkpoint inhibition (ICI) in recurrent high-grade gliomas (rHGG) report 7%-20% 6-month progression-free survival (PFS), while re-irradiation demonstrates 28%-39% 6-month PFS.

AIMS

We evaluate outcomes of patients treated with ICI and concurrent re-irradiation utilizing stereotactic body radiotherapy/fractionated stereotactic radiosurgery (SBRT) compared to ICI monotherapy.

METHODS AND RESULTS

Patients ≥18-years-old with rHGG (WHO grade III and IV) receiving ICI + SBRT or ICI monotherapy between January 1, 2016 and January 1, 2019 were included. Adverse events, 6-month PFS and overall survival (OS) were assessed. Log-rank tests were used to evaluate PFS and OS. Histogram analyses of apparent diffusion coefficient maps and dynamic contrast-enhanced magnetic resonance perfusion metrics were performed. Twenty-one patients with rHGG (ICI + SBRT: 16; ICI: 5) were included. The ICI + SBRT and ICI groups received a mean 7.25 and 6.2 ICI cycles, respectively. There were five grade 1, one grade 2 and no grade 3-5 AEs in the ICI + SBRT group, and four grade 1 and no grade 2-5 AEs in the ICI group. Median PFS was 2.85 and 1 month for the ICI + SBRT and ICI groups; median OS was 7 and 6 months among ICI + SBRT and ICI groups, respectively. There were significant differences in pre and posttreatment tumor volume in the cohort (12.35 vs. 20.51; p = .03), but not between treatment groups.

CONCLUSIONS

In this heavily pretreated cohort, ICI with re-irradiation utilizing SBRT was well tolerated. Prospective studies are warranted to evaluate potential therapeutic benefits to re-irradiation with ICI + SBRT in rHGG.

Combined anti-C1-INH and radiotherapy against glioblastoma

BACKGROUND

A more effective immune response against glioblastoma is needed in order to achieve better tumor control. Radiotherapy can induce anti-tumor mediated immune reactions, in addition to its dose response effects. The complement system can function as a bridge between innate and adaptive immune responses. Combining radiotherapy and complement activating therapy is theoretically interesting.

METHODS

Radiotherapy at 8 Gy × 2 was combined with treatment against C1-inhibitor (C1-INH), a potent inhibitor of activation of the classical pathway of the complement system. Anti-C1-INH was delivered as intratumoral injections. Fully immunocompetent Fischer 344 rats with NS1 glioblastoma tumors were treated. Survival was monitored as primary outcome. Models with either intracranial or subcutaneous tumors were evaluated separately.

RESULTS

In the intracranial setting, irradiation could prolong survival, but there was no additional survival gain as a result of anti-C1-INH treatment. In animals with subcutaneous tumors, combined radio-immunotherapy with anti-C1-INH and irradiation at 8 Gy × 2 significantly prolonged survival compared to control animals, whereas irradiation or anti-C1-INH treatment as single therapies did not lead to significantly increased survival compared to control animals.

CONCLUSIONS

Anti-C1-INH treatment could improve the efficacy of irradiation delivered at sub-therapeutic doses and delay tumor growth in the subcutaneous tumor microenvironment. In the intracranial setting, the doses of anti-C1-INH were not enough to achieve any survival effect in the present setting.

The radiobiology of TGFβ

Ionizing radiation is a pillar of cancer therapy that is deployed in more than half of all malignancies. The therapeutic effect of radiation is attributed to induction of DNA damage that kills cancers cells, but radiation also affects signaling that alters the composition of the tumor microenvironment by activating transforming growth factor β (TGFβ). TGFβ is a ubiquitously expressed cytokine that acts as biological lynchpin to orchestrate phenotypes, the stroma, and immunity in normal tissue; these activities are subverted in cancer to promote malignancy, a permissive tumor microenvironment and immune evasion. The radiobiology of TGFβ unites targets at the forefront of oncology-the DNA damage response and immunotherapy. The cancer cell intrinsic and extrinsic network of TGFβ responses in the irradiated tumor form a barrier to both genotoxic treatments and immunotherapy response. Here, we focus on the mechanisms by which radiation induces TGFβ activation, how TGFβ regulates DNA repair, and the dynamic regulation of the tumor immune microenvironment that together oppose effective cancer therapy. Strategies to inhibit TGFβ exploit fundamental radiobiology that may be the missing link to deploying TGFβ inhibitors for optimal patient benefit from cancer treatment.

Preoperative stereotactic radiosurgery in the management of brain metastases and gliomas

Stereotactic radiosurgery (SRS) is the delivery of a high dose ionizing radiation in a highly conformal manner, which allows for significant sparing of nearby healthy tissues. It is typically delivered in 1-5 sessions and has demonstrated safety and efficacy across multiple intracranial neoplasms and functional disorders. In the setting of brain metastases, postoperative and definitive SRS has demonstrated favorable rates of tumor control and improved cognitive preservation compared to conventional whole brain radiation therapy. However, the risk of local failure and treatment-related complications (e.g. radiation necrosis) markedly increases with larger postoperative treatment volumes. Additionally, the risk of leptomeningeal disease is significantly higher in patients treated with postoperative SRS. In the setting of high grade glioma, preclinical reports have suggested that preoperative SRS may enhance anti-tumor immunity as compared to postoperative radiotherapy. In addition to potentially permitting smaller target volumes, tissue analysis may permit characterization of DNA repair pathways and tumor microenvironment changes in response to SRS, which may be used to further tailor therapy and identify novel therapeutic targets. Building on the work from preoperative SRS for brain metastases and preclinical work for high grade gliomas, further exploration of this treatment paradigm in the latter is warranted. Presently, there are prospective early phase clinical trials underway investigating the role of preoperative SRS in the management of high grade gliomas. In the forthcoming sections, we review the biologic rationale for preoperative SRS, as well as pertinent preclinical and clinical data, including ongoing and planned prospective clinical trials.

Treatment of Brain Metastases: The Synergy of Radiotherapy and Immune Checkpoint Inhibitors

Brain metastases are a devastating sequela of common primary cancers (e.g., lung, breast, and skin) and have limited effective therapeutic options. Previously, systemic chemotherapy failed to demonstrate significant benefit in patients with brain metastases, but in recent decades, targeted therapies and more recently immune checkpoint inhibitors (ICIs) have yielded promising results in preclinical and clinical studies. Furthermore, there is significant interest in harnessing the immunomodulatory effects of radiotherapy (RT) to synergize with ICIs. Herein, we discuss studies evaluating the impact of RT dose and fractionation on the immune response, early studies supporting the synergistic interaction between RT and ICIs, and ongoing clinical trials assessing the benefit of combination therapy in patients with brain metastases.

The "Great Debate" at Melanoma Bridge 2021, December 2nd-4th, 2021

The Great Debate session at the 2021 Melanoma Bridge virtual congress (December 2-4) featured counterpoint views from experts on seven important issues in melanoma. The debates considered the use of adoptive cell therapy versus use of bispecific antibodies, mitogen-activated protein kinase (MAPK) inhibitors versus immunotherapy in the adjuvant setting, whether the use of corticosteroids for the management of side effects have an impact on outcomes, the choice of programmed death (PD)-1 combination therapy with cytotoxic T-lymphocyte-associated antigen (CTLA)-4 or lymphocyte-activation gene (LAG)-3, whether radiation is needed for brain metastases, when lymphadenectomy should be integrated into the treatment plan and then the last debate, telemedicine versus face-to-face. As with previous Bridge congresses, the debates were assigned by meeting Chairs and positions taken by experts during the debates may not have necessarily reflected their respective personal view. Audiences voted both before and after each debate.

Using Radiation Therapy to Prime and Propagate an Anti-tumor Immune Response Against Brain Tumors

Immunotherapies have demonstrated efficacy and survival benefits in some patients suffering from brain tumors; however, most do not respond and new approaches to enhance anti-tumor immunotherapeutic responses in the brain are needed. Radiotherapy remains a commonly used cancer treatment modality and can augment immunotherapeutic responses through multiple mechanisms. Recent preclinical studies may provide insight on how to optimally combine radiation and immunotherapies to maximize treatment efficacy. Unique aspects of the brain tumor microenvironment may play a critical role in limiting the successful application of immunotherapies in this location. Emerging studies suggest that such limits may be redressed through combination of immunotherapies with radiation therapy. In these settings, the latter may play a critical role in immunomodulating both tumor cells and the radiated brain tumor microenvironment. This review analyzes recent developments in combining radiation and immunotherapies to prime and better propagate anti-tumor immune response against brain tumors.

Preoperative Stereotactic Radiosurgery for Glioblastoma

Glioblastoma is a devastating primary brain tumor with a median overall survival of approximately 15 months despite the use of optimal modern therapy. While GBM has been studied for decades, modern therapies have allowed for a reduction in treatment-related toxicities, while the prognosis has largely been unchanged. Adjuvant stereotactic radiosurgery (SRS) was previously studied in GBM; however, the results were disappointing. SRS is a highly conformal radiation technique that permits the delivery of high doses of ionizing radiation in 1-5 sessions while largely sparing surrounding healthy tissues. Furthermore, studies have shown that the delivery of ablative doses of ionizing radiation within the central nervous system is associated with enhanced anti-tumor immunity. While SRS is commonly used in the definitive and adjuvant settings for other CNS malignancies, its role in the preoperative setting has become a topic of great interest due to the potential for reduced treatment volumes due to the treatment of an intact tumor, and a lower risk of nodular leptomeningeal disease and radiation necrosis. While early reports of SRS in the adjuvant setting for glioblastoma were disappointing, its role in the preoperative setting and its impact on the anti-tumor adaptive immune response is largely unknown. In this review, we provide an overview of GBM, discuss the potential role of preoperative SRS, and discuss the possible immunogenic effects of this therapy.

Dendritic Cells and Cancer Immunotherapy: The Adjuvant Effect

Dendritic cells (DCs) are immune specialized cells playing a critical role in promoting immune response against antigens, and may represent important targets for therapeutic interventions in cancer. DCs can be stimulated ex vivo with pro-inflammatory molecules and loaded with tumor-specific antigen(s). Protocols describing the specific details of DCs vaccination manufacturing vary widely, but regardless of the employed protocol, the DCs vaccination safety and its ability to induce antitumor responses is clearly established. Many years of studies have focused on the ability of DCs to provide overall survival benefits at least for a selection of cancer patients. Lessons learned from early trials lead to the hypothesis that, to improve the efficacy of DCs-based immunotherapy, this should be combined with other treatments. Thus, the vaccine’s ultimate role may lie in the combinatorial approaches of DCs-based immunotherapy with chemotherapy and radiotherapy, more than in monotherapy. In this review, we address some key questions regarding the integration of DCs vaccination with multimodality therapy approaches for cancer treatment paradigms.

Novel Strategies for Nanoparticle-Based Radiosensitization in Glioblastoma

Radiotherapy (RT) is one of the cornerstones in the current treatment paradigm for glioblastoma (GBM). However, little has changed in the management of GBM since the establishment of the current protocol in 2005, and the prognosis remains grim. Radioresistance is one of the hallmarks for treatment failure, and different therapeutic strategies are aimed at overcoming it. Among these strategies, nanomedicine has advantages over conventional tumor therapeutics, including improvements in drug delivery and enhanced antitumor properties. Radiosensitizing strategies using nanoparticles (NP) are actively under study and hold promise to improve the treatment response. We aim to describe the basis of nanomedicine for GBM treatment, current evidence in radiosensitization efforts using nanoparticles, and novel strategies, such as preoperative radiation, that could be synergized with nanoradiosensitizers.

Roles of Neutrophils in Glioma and Brain Metastases

Neutrophils, which are the most abundant circulating leukocytes in humans, are the first line of defense against bacterial and fungal infections. Recent studies have reported the role and importance of neutrophils in cancers. Glioma and brain metastases are the most common malignant tumors of the brain. The tumor microenvironment (TME) in the brain is complex and unique owing to the brain-blood barrier or brain-tumor barrier, which may prevent drug penetration and decrease the efficacy of immunotherapy. However, there are limited studies on the correlation between brain cancer and neutrophils. This review discusses the origin and functions of neutrophils. Additionally, the current knowledge on the correlation between neutrophil-to-lymphocyte ratio and prognosis of glioma and brain metastases has been summarized. Furthermore, the implications of tumor-associated neutrophil (TAN) phenotypes and the functions of TANs have been discussed. Finally, the potential effects of various treatments on TANs and the ability of neutrophils to function as a nanocarrier of drugs to the brain TME have been summarized. However, further studies are needed to elucidate the complex interactions between neutrophils, other immune cells, and brain tumor cells.

Low-Dose Radiation Potentiates the Propagation of Anti-Tumor Immunity against Melanoma Tumor in the Brain after In Situ Vaccination at a Tumor outside the Brain

Brain metastases develop in over 60% of advanced melanoma patients and negatively impact quality of life and prognosis. In a murine melanoma model, we previously showed that an in situ vaccination (ISV) regimen, combining radiation treatment and intratumoral (IT) injection of immunocytokine (IC: anti-GD2 antibody fused to IL2), along with the immune checkpoint inhibitor anti-CTLA-4, robustly eliminates peripheral flank tumors but only has modest effects on co-occurring intracranial tumors. In this study, we investigated the ability of low-dose radiation to the brain to potentiate anti-tumor immunity against a brain tumor when combined with ISV + anti-CTLA-4. B78 (GD2+, immunologically "cold") melanoma tumor cells were implanted into the flank and the right striatum of the brain in C57BL/6 mice. Flank tumors (50-150 mm3) were treated following a previously optimized ISV regimen [radiation (12 Gy × 1, treatment day 1), IT-IC (50 µg daily, treatment days 6-10), and anti-CTLA-4 (100 µg, treatment days 3, 6, 9)]. Mice that additionally received whole-brain radiation treatment (WBRT, 4 Gy × 1) on day 15 demonstrated significantly increased survival compared to animals that received ISV + anti-CTLA-4 alone, WBRT alone or no treatment (control) (P < 0.001, log-rank test). Timing of WBRT was critical, as WBRT administration on day 1 did not significantly enhance survival compared to ISV + anti-CTLA-4, suggesting that the effect of WBRT on survival might be mediated through immune modulation and not just direct tumor cell cytotoxicity. Modest increases in T cells (CD8+ and CD4+) and monocytes/macrophages (F4/80+) but no changes in FOXP3+ regulatory T cells (Tregs), were observed in brain melanoma tumors with addition of WBRT (on day 15) to ISV + anti-CTLA-4. Cytokine multiplex immunoassay revealed distinct changes in both intracranial melanoma and contralateral normal brain with addition of WBRT (day 15) to ISV + anti-CTLA-4, with notable significant changes in pro-inflammatory (e.g., IFNγ, TNFα and LIX/CXCL5) and suppressive (e.g., IL10, IL13) cytokines as well as chemokines (e.g., IP-10/CXCL10 and MIG/CXCL9). We tested the ability of the alkylphosphocholine analog, NM600, to deliver immunomodulatory radiation to melanoma brain tumors as a targeted radionuclide therapy (TRT). Yttrium-86 (86Y) chelated to NM600 was delivered intravenously by tail vein to mice harboring flank and brain melanoma tumors, and PET imaging demonstrated specific accumulation up to 72 h at each tumor site (∼12:1 brain tumor/brain and ∼8:1 flank tumor/muscle). When NM600 was chelated to therapeutic β-particle-emitting 90Y and administered on treatment day 13, T-cell infiltration and cytokine profiles were altered in melanoma brain tumor, like that observed for WBRT. Overall, our results demonstrate that addition of low-dose radiation, timed appropriately with ISV administration to tumors outside the brain, significantly increases survival in animals co-harboring melanoma brain tumors. This observation has potentially important translational implications as a treatment strategy for increasing the response of tumors in the brain to systemically administered immunotherapies.

Optimizing Flow Cytometric Analysis of Immune Cells in Samples Requiring Cryopreservation from Tumor-Bearing Mice

Most shared resource flow cytometry facilities do not permit analysis of radioactive samples. We are investigating low-dose molecular targeted radionuclide therapy (MTRT) as an immunomodulator in combination with in situ tumor vaccines and need to analyze radioactive samples from MTRT-treated mice using flow cytometry. Further, the sudden shutdown of core facilities in response to the COVID-19 pandemic has created an unprecedented work stoppage. In these and other research settings, a robust and reliable means of cryopreservation of immune samples is required. We evaluated different fixation and cryopreservation protocols of disaggregated tumor cells with the aim of identifying a protocol for subsequent flow cytometry of the thawed sample, which most accurately reflects the flow cytometric analysis of the tumor immune microenvironment of a freshly disaggregated and analyzed sample. Cohorts of C57BL/6 mice bearing B78 melanoma tumors were evaluated using dual lymphoid and myeloid immunophenotyping panels involving fixation and cryopreservation at three distinct points during the workflow. Results demonstrate that freezing samples after all staining and fixation are completed most accurately matches the results from noncryopreserved equivalent samples. We observed that cryopreservation of living, unfixed cells introduces a nonuniform alteration to PD1 expression. We confirm the utility of our cryopreservation protocol by comparing tumors treated with in situ tumor vaccines, analyzing both fresh and cryopreserved tumor samples with similar results. Last, we use this cryopreservation protocol with radioactive specimens to demonstrate potentially beneficial effector cell changes to the tumor immune microenvironment following administration of a novel MTRT in a dose- and time-dependent manner.

Exploiting Radiation Therapy to Restore Immune Reactivity of Glioblastoma

Glioblastoma (GBM) is among the most aggressive of brain tumors and confers a dismal prognosis despite advances in surgical technique, radiation delivery methods, chemotherapy, and tumor-treating fields. While immunotherapy (IT) has improved the care of several adult cancers with previously dismal prognoses, monotherapy with IT in GBM has shown minimal response in first recurrence. Recent discoveries in lymphatics and evaluation of blood brain barrier offer insight to improve the use of ITs and determine the best combinations of therapies, including radiation. We highlight important features of the tumor immune microenvironment in GBM and potential for combining radiation and immunotherapy to improve prognosis in this devastating disease.

Neoadjuvant durvalumab with or without stereotactic body radiotherapy in patients with early-stage non-small-cell lung cancer: a single-centre, randomised phase 2 trial

BACKGROUND

Previous phase 2 trials of neoadjuvant anti-PD-1 or anti-PD-L1 monotherapy in patients with early-stage non-small-cell lung cancer have reported major pathological response rates in the range of 15-45%. Evidence suggests that stereotactic body radiotherapy might be a potent immunomodulator in advanced non-small-cell lung cancer (NSCLC). In this trial, we aimed to evaluate the use of stereotactic body radiotherapy in patients with early-stage NSCLC as an immunomodulator to enhance the anti-tumour immune response associated with the anti-PD-L1 antibody durvalumab.

METHODS

We did a single-centre, open-label, randomised, controlled, phase 2 trial, comparing neoadjuvant durvalumab alone with neoadjuvant durvalumab plus stereotactic radiotherapy in patients with early-stage NSCLC, at NewYork-Presbyterian and Weill Cornell Medical Center (New York, NY, USA). We enrolled patients with potentially resectable early-stage NSCLC (clinical stages I-IIIA as per the 7th edition of the American Joint Committee on Cancer) who were aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0 or 1. Eligible patients were randomly assigned (1:1) to either neoadjuvant durvalumab monotherapy or neoadjuvant durvalumab plus stereotactic body radiotherapy (8 Gy × 3 fractions), using permuted blocks with varied sizes and no stratification for clinical or molecular variables. Patients, treating physicians, and all study personnel were unmasked to treatment assignment after all patients were randomly assigned. All patients received two cycles of durvalumab 3 weeks apart at a dose of 1·12 g by intravenous infusion over 60 min. Those in the durvalumab plus radiotherapy group also received three consecutive daily fractions of 8 Gy stereotactic body radiotherapy delivered to the primary tumour immediately before the first cycle of durvalumab. Patients without systemic disease progression proceeded to surgical resection. The primary endpoint was major pathological response in the primary tumour. All analyses were done on an intention-to-treat basis. This trial is registered with ClinicalTrial.gov, NCT02904954, and is ongoing but closed to accrual.

FINDINGS

Between Jan 25, 2017, and Sept 15, 2020, 96 patients were screened and 60 were enrolled and randomly assigned to either the durvalumab monotherapy group (n=30) or the durvalumab plus radiotherapy group (n=30). 26 (87%) of 30 patients in each group had their tumours surgically resected. Major pathological response was observed in two (6·7% [95% CI 0·8-22·1]) of 30 patients in the durvalumab monotherapy group and 16 (53·3% [34·3-71·7]) of 30 patients in the durvalumab plus radiotherapy group. The difference in the major pathological response rates between both groups was significant (crude odds ratio 16·0 [95% CI 3·2-79·6]; p<0·0001). In the 16 patients in the dual therapy group with a major pathological response, eight (50%) had a complete pathological response. The second cycle of durvalumab was withheld in three (10%) of 30 patients in the dual therapy group due to immune-related adverse events (grade 3 hepatitis, grade 2 pancreatitis, and grade 3 fatigue and thrombocytopaenia). Grade 3-4 adverse events occurred in five (17%) of 30 patients in the durvalumab monotherapy group and six (20%) of 30 patients in the durvalumab plus radiotherapy group. The most frequent grade 3-4 events were hyponatraemia (three [10%] patients in the durvalumab monotherapy group) and hyperlipasaemia (three [10%] patients in the durvalumab plus radiotherapy group). Two patients in each group had serious adverse events (pulmonary embolism [n=1] and stroke [n=1] in the durvalumab monotherapy group, and pancreatitis [n=1] and fatigue [n=1] in the durvalumab plus radiotherapy group). No treatment-related deaths or deaths within 30 days of surgery were reported.

INTERPRETATION

Neoadjuvant durvalumab combined with stereotactic body radiotherapy is well tolerated, safe, and associated with a high major pathological response rate. This neoadjuvant strategy should be validated in a larger trial.

FUNDING

AstraZeneca.

Neuroinflammatory changes of the normal brain tissue in cured mice following combined radiation and anti-PD-1 blockade therapy for glioma

The efficacy of combining radiation therapy with immune checkpoint inhibitor blockade to treat brain tumors is currently the subject of multiple investigations and holds significant therapeutic promise. However, the long-term effects of this combination therapy on the normal brain tissue are unknown. Here, we examined mice that were intracranially implanted with murine glioma cell line and became long-term survivors after treatment with a combination of 10 Gy cranial irradiation (RT) and anti-PD-1 checkpoint blockade (aPD-1). Post-mortem analysis of the cerebral hemisphere contralateral to tumor implantation showed complete abolishment of hippocampal neurogenesis, but neural stem cells were well preserved in subventricular zone. In addition, we observed a drastic reduction in the number of mature oligodendrocytes in the subcortical white matter. Importantly, this observation was evident specifically in the combined (RT + aPD-1) treatment group but not in the single treatment arm of either RT alone or aPD-1 alone. Elimination of microglia with a small molecule inhibitor of colony stimulated factor-1 receptor (PLX5622) prevented the loss of mature oligodendrocytes. These results identify for the first time a unique pattern of normal tissue changes in the brain secondary to combination treatment with radiotherapy and immunotherapy. The results also suggest a role for microglia as key mediators of the adverse treatment effect.

Role of Neutrophils and Myeloid-Derived Suppressor Cells in Glioma Progression and Treatment Resistance

Recent efforts in brain tumor research have been directed towards the modulation of the immune system for therapeutic interventions. Several human cancers, including gliomas, are infiltrated with immune cell types-including neutrophils and myeloid-derived suppressor cells-that contribute to tumor progression, invasiveness, and treatment resistance. The role of tumor-associated neutrophils and myeloid-derived suppressor cells in cancer biology remains elusive, as these cells can exert a multitude of pro-tumor and antitumor effects. In this review, we provide the current understanding and novel insights on the role of neutrophils and myeloid-derived suppressor cells in glioma progression and treatment resistance, as well as the mechanisms of pleiotropic behaviors in these cells during disease progression, with an emphasis on possible strategies to reprogram these cells towards their antitumor actions.

Stereotatic radiotherapy in metastatic non-small cell lung cancer: Combining immunotherapy and radiotherapy with a focus on liver metastases

Presence of liver metastases correlates with worse survival and response to any treatments. This may be due to the microenvironment of liver which leads tumor to escape from Immune System. Stereotactic Body Radiation Therapy may help to sensitize Immune System and to improve the immunotherapy effect. Interest is being directed toward combining Immune-Checkpoint Inhibitors with radiotherapy to improve response to immunotherapy. However, the mechanisms by which radiation induces anti-tumor T-cells remain unclear. Preclinical studies founded radiotherapy enhances antitumor immune responses, increasing tumor antigen release, and inducing T-cell infiltration. Radiotherapy is under investigation for its ability to enhance responses to immunotherapy. Nevertheless, how to optimally deliver combination therapy regarding dose-fractionation and timing of radiotherapy is unknown. The aim of this review is to explore the role of Stereotactic Body Radiation Therapy in metastatic non-small cell lung cancer, focusing on patients with liver metastases, and the possible immunological implications combining immunotherapy and radiotherapy.

Convection-enhanced delivery of temozolomide and whole cell tumor immunizations in GL261 and KR158 experimental mouse gliomas

Background

Glioblastomas (GBM) are therapy-resistant tumors with a profoundly immunosuppressive tumor microenvironment. Chemotherapy has shown limited efficacy against GBM. Systemic delivery of chemotherapeutic drugs is hampered by the difficulty of achieving intratumoral levels as systemic toxicity is a dose-limiting factor. Although some of its effects might be mediated by immune reactivity, systemic chemotherapy can also inhibit induced or spontaneous antitumor immune reactivity. Convection-enhanced delivery of temozolomide (CED-TMZ) can tentatively increase intratumoral drug concentration while reducing systemic side effects. The objective of this study was to evaluate the therapeutic effect of intratumorally delivered temozolomide in combination with immunotherapy and whether such therapy can generate a cellular antitumor immune response.

Methods

Single bolus intratumoral injection and 3-day mini-osmotic pumps (Alzet®) were used to deliver intratumoral TMZ in C57BL6 mice bearing orthotopic gliomas. Immunotherapy consisted of subcutaneous injections of irradiated GL261 or KR158 glioma cells. Tumor size and intratumoral immune cell populations were analyzed by immunohistochemistry.

Results

Combined CED-TMZ and immunotherapy had a synergistic antitumor effect in the GL261 model, compared to CED-TMZ or immunotherapy as monotherapies. In the KR158 model, immunization cured a small proportion of the mice whereas addition of CED-TMZ did not have a synergistic effect. However, CED-TMZ as monotherapy prolonged the median survival. Moreover, TMZ bolus injection in the GL261 model induced neurotoxicity and lower cure rate than its equivalent dose delivered by CED. In addition, we found that T-cells were the predominant cells responsible for the TMZ antitumor effect in the GL261 model. Finally, CED-TMZ combined with immunotherapy significantly reduced tumor volume and increased the intratumoral influx of T-cells in both models.

Conclusions

We show that immunotherapy synergized with CED-TMZ in the GL261 model and cured animals in the KR158 model. Single bolus administration of TMZ was effective with a narrower therapeutic window than CED-TMZ. Combined CED-TMZ and immunotherapy led to an increase in the intratumoral influx of T-cells. These results form part of the basis for the translation of the therapy to patients with GBM but the dosing and timing of delivery will have to be explored in depth both experimentally and clinically.

Efficient identification of novel anti-glioma lead compounds by machine learning models

Glioblastoma multiforme (GBM) is the most devastating and widespread primary central nervous system tumor. Pharmacological treatment of this malignance is limited by the selective permeability of the blood-brain barrier (BBB) and relies on a single drug, temozolomide (TMZ), thus making the discovery of new compounds challenging and urgent. Therefore, aiming to discover new anti-glioma drugs, we developed robust machine learning models for predicting anti-glioma activity and BBB penetration ability of new compounds. Using these models, we prioritized 41 compounds from our in-house library of compounds, for further in vitro testing against three glioma cell lines and astrocytes. Subsequently, the most potent and selective compounds were resynthesized and tested in vivo using an orthotopic glioma model. This approach revealed two lead candidates, 4m and 4n, which efficiently decreased malignant glioma development in mice, probably by inhibiting thioredoxin reductase activity, as shown by our enzymological assays. Moreover, these two compounds did not promote body weight reduction, death of animals, or altered hematological and toxicological markers, making then good candidates for lead optimization as anti-glioma drug candidates.

A preliminary Study on the Effect of Head and Neck Chemoradiotherapy on Systematic Immunity

Background

This study was designed initially to explore the effect of chemoradiotherapy on patients diagnosed with head and neck cancer (HNC) with respect to the alteration of systematic immunity.

Methods

We did a retrospective study enrolling patients received concurrent chemoradiotherapy (CCRT), with or without induction chemotherapy (IC). Blood tests were performed before IC, before and after CCRT. Flow cytometric analysis and turbidimetric inhibition immunoassay were used for detection.

Results

A total number of 58 patients were included from April 1, 2018, to March 31, 2019. Levels of immunoglobulins (Ig), including IgA, IgG, and IgM, declined after 2 to 3 cycles of IC and CCRT, respectively. Serum level of total hemolytic complement (CH50) increased (P < .001) after IC, but kept stably post-CCRT. Natural killer (NK) cells decreased (P < .01) after IC and enhanced (P < .001) post-CCRT. The number of CD3⁺CD4⁺ T cells got increased (P < .01) after IC and decreased (P < .001) post-CCRT. Consistently, both IC and CCRT induced the increase in CD3⁺CD8⁺ T cells significantly (P < .001 vs P < .01).

Conclusion

Both radiotherapy (RT) and chemotherapy (CT) induced dual effect of immune response. Concurrent chemoradiotherapy created an active immune response based on the effect induced by IC, suggesting that RT exerted a potential function on mobilizing immune system.

Targeting Myeloid Cells in Combination Treatments for Glioma and Other Tumors

Myeloid cells constitute a significant part of the immune system in the context of cancer, exhibiting both immunostimulatory effects, through their role as antigen presenting cells, and immunosuppressive effects, through their polarization to myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages. While they are rarely sufficient to generate potent anti-tumor effects on their own, myeloid cells have the ability to interact with a variety of immune populations to aid in mounting an appropriate anti-tumor immune response. Therefore, myeloid therapies have gained momentum as a potential adjunct to current therapies such as immune checkpoint inhibitors (ICIs), dendritic cell vaccines, oncolytic viruses, and traditional chemoradiation to enhance therapeutic response. In this review, we outline critical pathways involved in the recruitment of the myeloid population to the tumor microenvironment and in their polarization to immunostimulatory or immunosuppressive phenotypes. We also emphasize existing strategies of modulating myeloid recruitment and polarization to improve anti-tumor immune responses. We then summarize current preclinical and clinical studies that highlight treatment outcomes of combining myeloid targeted therapies with other immune-based and traditional therapies. Despite promising results from reports of limited clinical trials thus far, there remain challenges in optimally harnessing the myeloid compartment as an adjunct to enhancing anti-tumor immune responses. Further large Phase II and ultimately Phase III clinical trials are needed to elucidate the treatment benefit of combination therapies in the fight against cancer.

Late autophagy inhibitor chloroquine improves efficacy of the histone deacetylase inhibitor SAHA and temozolomide in gliomas

Glioblastoma multiforme is the most aggressive type of primary brain tumor associated with few therapeutic opportunities and poor prognosis. In this study, we evaluated the efficacy of combining temozolomide (TMZ) with suberoylanilide hydroxamic acid (SAHA) - a specific histone deacetylases inhibitor - in glioma models in vitro and in vivo. In glioma cell lines, combined TMZ/SAHA promoted more cytotoxicity, G2/M arrest and apoptosis than either drugs alone. G2/M arrest was detected as soon as 24 h post drug exposure and preceded apoptosis, which occurred from 72 h treatment. TMZ and SAHA, alone or combined, also stimulated autophagy as evaluated by means of acridine orange staining and immunodetection of LC3I-II conversion and p62/SQSTM1 degradation. Time-course of autophagy accompanied G2/M arrest and preceded apoptosis, and blockage of late steps of autophagy with chloroquine (CQ) augmented SAHA/TMZ toxicity leading to apoptosis. In orthotopic gliomas in vivo, combined SAHA/TMZ showed better antitumor efficacy than either drugs alone, and adding CQ to the regimen improved antiglioma effects of SAHA and TMZ monotherapies without further benefit on combined SAHA/TMZ. In summary, the herein presented data suggest that autophagy acts as a protective response that impairs efficacy of SAHA and TMZ. Inhibiting autophagy termination with CQ may offer means to improve antitumor effects of SAHA and TMZ in gliomas and possibly other cancers.

Radiation and Immunotherapy in High-grade Gliomas: Where Do We Stand?

High-grade glioma is the most common primary brain tumor, with glioblastoma multiforme (GBM) accounting for 52% of all brain tumors. The current standard of care (SOC) of GBM involves surgery followed by adjuvant fractionated radiotherapy and chemotherapy. However, little progress has been made in extending overall survival, progression-free survival, and quality of life. Attempts to characterize and customize treatment of GBM have led to mitigating the deleterious effects of radiotherapy using hypofractionated radiotherapy, as well as various immunotherapies as a promising strategy for the incurable disease. A combination of radiotherapy and immunotherapy may prove to be even more effective than either alone, and preclinical evidence suggests that hypofractionated radiotherapy can actually prime the immune system to make immunotherapy more effective. This review addresses the complications of the current radiotherapy regimen, various methods of immunotherapy, and preclinical and clinical data from combined radioimmunotherapy trials.

Genetically Engineered T-Cells for Malignant Glioma: Overcoming the Barriers to Effective Immunotherapy

Malignant gliomas carry a dismal prognosis. Conventional treatment using chemo- and radiotherapy has limited efficacy with adverse events. Therapy with genetically engineered T-cells, such as chimeric antigen receptor (CAR) T-cells, may represent a promising approach to improve patient outcomes owing to their potential ability to attack highly infiltrative tumors in a tumor-specific manner and possible persistence of the adaptive immune response. However, the unique anatomical features of the brain and susceptibility of this organ to irreversible tissue damage have made immunotherapy especially challenging in the setting of glioma. With safety concerns in mind, multiple teams have initiated clinical trials using CAR T-cells in glioma patients. The valuable lessons learnt from those trials highlight critical areas for further improvement: tackling the issues of the antigen presentation and T-cell homing in the brain, immunosuppression in the glioma microenvironment, antigen heterogeneity and off-tumor toxicity, and the adaptation of existing clinical therapies to reflect the intricacies of immune response in the brain. This review summarizes the up-to-date clinical outcomes of CAR T-cell clinical trials in glioma patients and examines the most pressing hurdles limiting the efficacy of these therapies. Furthermore, this review uses these hurdles as a framework upon which to evaluate cutting-edge pre-clinical strategies aiming to overcome those barriers.

Targeting Innate Immunity to Enhance the Efficacy of Radiation Therapy

Radiation continues to play a major role in the treatment of almost every cancer type. Traditional radiation studies focused on its ability to damage DNA, but recent evidence has demonstrated that a key mechanism driving the efficacy of radiation in vivo is the immune response triggered in irradiated tissue. Innate immune cells including macrophages, dendritic cells, and natural killer cells are key mediators of the radiation-induced immune response. They regulate the sensing of radiation-mediated damage and subsequent radiation-induced inflammation. Given the importance of innate immune cells as determinants of the post-radiation anti-tumor immune response, much research has been devoted to identify ways to both enhance the innate immune response and prevent their ability to suppress ongoing immune responses. In this review, we will discuss how the innate immune system shapes anti-tumor immunity following radiation and highlight key strategies directed at the innate immune response to enhance the efficacy of radiation.

Hyperprogression after anti-programmed cell death ligand-1 therapy in a patient with recurrent metastatic urothelial bladder carcinoma following first-line cisplatin-based chemotherapy: a case report

Background

Immune checkpoint blockade targeting programmed cell death ligand-1 (PD-L1)/programmed death-1 (PD-1) signaling was approved recently for locally advanced and metastatic urothelial bladder carcinoma (UBC). Some patients experience a very rapid tumor progression, rather than clinical benefit, from anti-PD-L1/PD-1 therapy.

Case presentation

A 58-year-old male diagnosed with non-muscle-invasive bladder cancer 3 years ago received transurethral resection of bladder tumor (TURBT) and intravesical chemotherapy. TURBT was repeated a year later for recurrent and progressive UBC. Following further disease progression, he received a radical cystectomy (RC), pathologically staged as T2bN2M0, and adjuvant cisplatin-containing combination chemotherapy. When his disease progressed to metastatic UBC, he was started on anti-PD-L1 monotherapy and experienced ultrarapid disease progression within 2 months; imaging scans ruled out pseudoprogression. We observed a fourfold increase in tumor growth rate, defined as the ratio of post- to pretreatment rates. Next-generation sequencing of formalin-fixed paraffin-embedded RC tissues showed MDM2 amplification without MDM4 amplification, EGFR aberrations, or DNMT3A alterations. Immunohistochemistry showed grade 2+ PD-L1 labeling intensity of the RC tissues, with 15%–25% and 5%–10% PD-LI immunopositive tumor cells and tumor-infiltrating immune cells, respectively.

Conclusion

Even in cases with PD-L1-positive tumors, MDM2 gene amplification may result in failure of anti-PD-L1 immunotherapy and rapid tumor growth. Therefore, genomic profiling may identify patients at risk for hyperprogression before immunotherapy.

Radiotherapy as a New Player in Immuno-Oncology

Recent development in radiation biology has revealed potent immunogenic properties of radiotherapy in cancer treatments. However, antitumor immune effects of radiotherapy are limited by the concomitant induction of radiation-dependent immunosuppressive effects. In the growing era of immunotherapy, combining radiotherapy with immunomodulating agents has demonstrated enhancement of radiation-induced antitumor immune activation that correlated with improved treatment outcomes. Yet, how to optimally deliver combination therapy regarding dose-fractionation and timing of radiotherapy is largely unknown. Future prospective testing to fine-tune this promising combination of radiotherapy and immunotherapy is warranted.

Irradiation to Improve the Response to Immunotherapeutic Agents in Glioblastomas

Purpose

Glioblastoma (GBM) remains an incurable disease despite extensive treatment with surgical resection, irradiation, and temozolomide. In line with many other forms of aggressive cancers, GBM is currently under consideration as a target for immunotherapy. However, GBM tends to be nonimmunogenic and exhibits a microenvironment with few or no effector T cells, a relatively low nonsynonymous somatic mutational load, and a low predicted neoantigen burden. GBM also exploits a multitude of immunosuppressive strategies.

Methods and Materials

A number of immunotherapeutic approaches have been tested with disappointing results. A rationale exists to combine immunotherapy and radiation therapy, which can induce an immunogenic form of cell death with T-cell activation and tumor infiltration.

Results

Various immunotherapy agents, including immune checkpoint modulators, transforming growth factor beta receptor inhibitors, and indoleamine-2,3-dioxygenase inhibitors, have been evaluated with irradiation in preclinical GBM models, with promising results, and are being further tested in clinical trials.

Conclusions

This review aims to present the basic rationale behind this emerging complementary therapeutic approach in GBM, appraise the current preclinical and clinical data, and discuss the future challenges in improving the antitumor immune response.

Immune recognition of irradiated cancer cells

Ionizing irradiation has been extensively employed for the clinical management of solid tumors, with therapeutic or palliative intents, for decades. Until recently, radiation therapy (RT) was believed to mediate antineoplastic activity mostly (if not only) as a consequence of cancer cell-intrinsic effects. Indeed, the macromolecular damage imposed to malignant cells by RT initiates one or multiple signal transduction cascades that drive a permanent proliferative arrest (cellular senescence) or regulated cell death. Both these phenomena show a rather linear dose-response correlation. However, RT also mediates consistent immunological activity, not only as an "on-target effect" originating within irradiated cancer cells, but also as an "off-target effect" depending on the interaction between RT and stromal, endothelial, and immune components of the tumor microenvironment. Interestingly, the immunological activity of RT does not exhibit linear dose-response correlation. Here, we discuss the mechanisms whereby RT alters the capacity of the immune system to recognize and eliminate irradiated cancer cells, either as an "on-target" or as on "off-target" effect. In particular, we discuss the antagonism between the immunostimulatory and immunosuppressive effects of RT as we delineate combinatorial strategies to boost the former at the expenses of the latter.

Comparative analysis of the effect of different radiotherapy regimes on lymphocyte and its subpopulations in breast cancer patients

PURPOSE

The aim of this study was to determine whether different radiotherapy (RT) fractionation schemes induce disparate effects on lymphocyte and its subsets in breast cancer patients.

METHODS

60 female patients diagnosed with breast cancer were recruited in this study after receiving modified radical mastectomy and were randomly divided into two groups. One group received irradiation at a standard dose of 50 Gy in 25 fractions and the other at a dose of 40.3 Gy in 13 fractions. Both total lymphocyte count and its composition were recorded at three timepoints: right before the radiation treatment (T0), immediately after the last fraction of radiotherapy (T1) and 6 months after irradiation therapy ended (T2).

RESULTS

Both groups experienced temporal lymphopenia after finishing local radiation (T1) (13F T0 vs. T1 1570.6 ± 243.9 vs. 940.6 ± 141.8, **p < 0.01; 25F T0 vs. T1 1620.5 ± 280.2 vs. 948.5 ± 274.6, **p < 0.01), while the lymphocyte count recovered at follow-up time (T2), and the cell count in the hypofractionation group (13F) was higher than the standard fraction group (25F) (13F vs. 25F 1725.6 ± 225.6 vs. 1657.5 ± 242.4, *p < 0.05). With respect to the composition of lymphocyte, we found T cell, B cell, and NK cell reacted differently to different radiotherapy protocols.

CONCLUSIONS

Different RT protocols impose different impacts on immunity, leading us to further explore the optimal radiotherapy regimes to synergy with immunotherapy.

Advances in Radiotherapy for Glioblastoma

External beam radiotherapy (RT) has long played a crucial role in the treatment of glioblastoma. Over the past several decades, significant advances in RT treatment and image-guidance technology have led to enormous improvements in the ability to optimize definitive and salvage treatments. This review highlights several of the latest developments and controversies related to RT, including the treatment of elderly patients, who continue to be a fragile and vulnerable population; potential salvage options for recurrent disease including reirradiation with chemotherapy; the latest imaging techniques allowing for more accurate and precise delineation of treatment volumes to maximize the therapeutic ratio of conformal RT; the ongoing preclinical and clinical data regarding the combination of immunotherapy with RT; and the increasing evidence of cancer stem-cell niches in the subventricular zone which may provide a potential target for local therapies. Finally, continued development on many fronts have allowed for modestly improved outcomes while at the same time limiting toxicity.

Integration of radiation and immunotherapy in breast cancer - Treatment implications

Radiation therapy (RT) has been successfully used in the treatment of breast cancer (BC) for over a century. While historically thought to be immunosuppressive, new data have shown that RT can work together with the immune system to eliminate cancer. It can cause immunogenic cell death and facilitate tumor neoantigen presentation and cross-priming of tumor-specific T-lymphocytes, turning irradiated tumor into an in-situ vaccine. Unfortunately, due to various immune escape mechanism put in place by the tumor, RT alone rarely results in a systemic response of metastatic disease sites (known as the abscopal effect). Immunotherapy, a series of agents designed to stimulate the immune system in order to generate tumor-specific immune response, is showing promise in treatment of various cancers, including BC, and can be an ideal complement to RT in stimulating a systemic immune response to reject the tumor cells. This review discusses the mechanisms in which RT can trigger an immune response for tumor rejection, and provide emerging preclinical and clinical data of combination immunoradiotherapy, and its potential in treating BC.