Brain metastases

Manganese-based virus-mimicking nanomedicine with triple immunomodulatory functions inhibits breast cancer brain metastasis

Hindered by the challenges of blood-brain barrier (BBB) hindrance, tumor heterogeneity and immunosuppressive microenvironment, patients with breast cancer brain metastasis have yet to benefit from current clinical treatments, experiencing instead a decline in quality of life due to radiochemotherapy. While virus-mimicking nanosystems (VMN) mimicking viral infection processes show promise in treating peripheral tumors, the inability to modulate the immunosuppressive microenvironment limits the efficacy against brain metastasis. Accordingly, a VMN-based triple immunomodulatory strategy is initially proposed, aiming to activate innate and adaptive immune responses and reverse the immunosuppressive microenvironment. Here, manganese-based virus-mimicking nanomedicine (Vir-HD@HM) with intratumoral drug enrichment is engineered. Vir-HD@HM can induce the immune response through the activation of cGAS-STING by mimicking the in vivo infection process of herpesviruses. Meanwhile, DNAzyme mimicking the genome can rescue the epigenetic silencing of PTEN with the assistance of Mn2+, thus ameliorating the immunosuppressive metastatic microenvironment and achieving synergistic sensitizing therapeutic efficacy. In vivo experiments substantiate the efficacy of Vir-HD@HM in recruiting NK cells and CD8+ T cells to metastatic foci, inhibiting Treg cells infiltration, and prolonging murine survival without adjunctive radiochemotherapy. This study demonstrates that Vir-HD@HM with triple immunomodulation offers an encouraging therapeutic option for patients with brain metastasis.

Hyperbaric oxygen therapy as an adjunt treatment for glioma and brain metastasis: a literature review

The incidence and mortality rates of malignant tumors are increasing annually, with gliomas and brain metastases linked to a poor prognosis. Hyperbaric oxygen therapy is a promising treatment modality for both gliomas and brain metastases. It can alleviate tumor hypoxia and enhance radiosensitivity. When combined with other treatments for gliomas, this therapy has the potential to enhance survival rates. This review addresses the progress in research on the use of hyperbaric oxygen therapy combined with radiotherapy. For brain metastases, the combination of hyperbaric oxygen therapy and stereotactic radiosurgery is both feasible and advantagenous. This combination not only offers protection against radiation-induced brain injury but also supports the recovery of neurological and motor functions. The incidence of adverse reactions to hyperbaric oxygen therapy is relatively low, and it is safe and manageable. Future efforts should be made to investigate the mechanisms by which hyperbaric oxygen therapy combined with radiotherapy treats gliomas and brain metastases, optimize protection of the combined treatment against brain injury, minimizing adverse reactions, conducting multidisciplinary research and clinical trials, and training healthcare providers to facilitate broader clinical application.

Hormonal and neuronal interactions shaping the brain metastatic microenvironment

Metastatic progression drives the majority of cancer-related fatalities, and involvement of the central nervous system (CNS) poses especially formidable challenges to patients and clinicians. Brain metastases (BrM), commonly originate from lung, breast and melanoma cancers, and carry disproportionately poor outcomes. Although therapeutic advances have extended survival for many extracranial tumors, BrM incidence continues to climb-underscoring critical knowledge gaps in understanding the unique biology of tumor colonization in the CNS. While definitive evidence remains limited, a growing focus on cancer neuroscience-especially regarding hormone dependent cancer cells in the brain-has begun to reveal that factors normally regulated by sex steroids and neurosteroids may similarly influence the specialized metastatic microenvironment in the CNS. Steroid hormones can permeate the blood-brain barrier (BBB) or be synthesized de novo by astrocytes and other CNS-resident cells, potentially influencing processes such as inflammation, synaptic plasticity, and immune surveillance. However, how these hormonal pathways are co-opted by disseminated cancer cells remains unclear. Here, we review the complex hormonal landscape of the adult brain and examine how neuroendocrine-immune interactions, often regulated by sex hormones, may support metastatic growth. We discuss the interplay between systemic hormones, local steroidogenesis, and tumor adaptation to identify novel therapeutic opportunities.

Isoliquiritigenin reduces brain metastasis by circNAV3-ST6GALNAC5-EGFR axis in triple-negative breast cancer

Brain metastasis (BM) is a serious complication of increasing incidence in patients with advanced breast cancer, which is characterized by swift deterioration in quality of life with few efficient therapy strategies. There is an urgent clinical requirement to devise potent therapeutic strategies for the prevention and management of brain metastases. Here, we report isoliquiritigenin (ISL), a key bioactive substance extracted from licorice root, which effectively inhibited triple-negative breast cancer (TNBC) brain metastasis (BM) by downregulation of circNAV3. CircRNAs expression analyses and functional studies, coupled with clinical significance investigations identified circNAV3 as a key molecule promoting TNBC BM. Functionally, circNAV3 could promote proliferation, migration, invasion, angiogenesis and capacity to penetrate the blood-brain barrier of TNBC cells. Mechanistically, circNAV3 could competitively bind with miR-4262, hence intercepting the suppressive effect of miR-4262 on ST6GALNAC5. Subsequently, this interplay enhanced EGFR sialylation and activation, initiating the PI3K/Akt pathway and ultimately fostering the development of TNBC brain metastases. In conclusion, our research establishes that ISL impede the initiation and advancement of TNBC brain metastasis by modulation of circNAV3/miR-4262/ST6GALNAC5/EGFR axis, laying a theoretical groundwork for the therapeutic use of ISL in this scenario.

Interaction of major facilitator superfamily domain containing 2A with the blood-brain barrier

The functional and structural integrity of the blood-brain barrier is crucial in maintaining homeostasis in the brain microenvironment; however, the molecular mechanisms underlying the formation and function of the blood-brain barrier remain poorly understood. The major facilitator superfamily domain containing 2A has been identified as a key regulator of blood-brain barrier function. It plays a critical role in promoting and maintaining the formation and functional stability of the blood-brain barrier, in addition to the transport of lipids, such as docosahexaenoic acid, across the blood-brain barrier. Furthermore, an increasing number of studies have suggested that major facilitator superfamily domain containing 2A is involved in the molecular mechanisms of blood-brain barrier dysfunction in a variety of neurological diseases; however, little is known regarding the mechanisms by which major facilitator superfamily domain containing 2A affects the blood-brain barrier. This paper provides a comprehensive and systematic review of the close relationship between major facilitator superfamily domain containing 2A proteins and the blood-brain barrier, including their basic structures and functions, cross-linking between major facilitator superfamily domain containing 2A and the blood-brain barrier, and the in-depth studies on lipid transport and the regulation of blood-brain barrier permeability. This comprehensive systematic review contributes to an in-depth understanding of the important role of major facilitator superfamily domain containing 2A proteins in maintaining the structure and function of the blood-brain barrier and the research progress to date. This will not only help to elucidate the pathogenesis of neurological diseases, improve the accuracy of laboratory diagnosis, and optimize clinical treatment strategies, but it may also play an important role in prognostic monitoring. In addition, the effects of major facilitator superfamily domain containing 2A on blood-brain barrier leakage in various diseases and the research progress on cross-blood-brain barrier drug delivery are summarized. This review may contribute to the development of new approaches for the treatment of neurological diseases.

Semi-Supervised Learning Allows for Improved Segmentation With Reduced Annotations of Brain Metastases Using Multicenter MRI Data

BACKGROUND

Deep learning-based segmentation of brain metastases relies on large amounts of fully annotated data by domain experts. Semi-supervised learning offers potential efficient methods to improve model performance without excessive annotation burden.

PURPOSE

This work tests the viability of semi-supervision for brain metastases segmentation.

STUDY TYPE

Retrospective.

SUBJECTS

There were 156, 65, 324, and 200 labeled scans from four institutions and 519 unlabeled scans from a single institution. All subjects included in the study had diagnosed with brain metastases.

FIELD STRENGTH/SEQUENCES

1.5 T and 3 T, 2D and 3D T1-weighted pre- and post-contrast, and fluid-attenuated inversion recovery (FLAIR).

ASSESSMENT

Three semi-supervision methods (mean teacher, cross-pseudo supervision, and interpolation consistency training) were adapted with the U-Net architecture. The three semi-supervised methods were compared to their respective supervised baseline on the full and half-sized training.

STATISTICAL TESTS

Evaluation was performed on a multinational test set from four different institutions using 5-fold cross-validation. Method performance was evaluated by the following: the number of false-positive predictions, the number of true positive predictions, the 95th Hausdorff distance, and the Dice similarity coefficient (DSC). Significance was tested using a paired samples t test for a single fold, and across all folds within a given cohort.

RESULTS

Semi-supervision outperformed the supervised baseline for all sites with the best-performing semi-supervised method achieved an on average DSC improvement of 6.3% ± 1.6%, 8.2% ± 3.8%, 8.6% ± 2.6%, and 15.4% ± 1.4%, when trained on half the dataset and 3.6% ± 0.7%, 2.0% ± 1.5%, 1.8% ± 5.7%, and 4.7% ± 1.7%, compared to the supervised baseline on four test cohorts. In addition, in three of four datasets, the semi-supervised training produced equal or better results than the supervised models trained on twice the labeled data.

DATA CONCLUSION

Semi-supervised learning allows for improved segmentation performance over the supervised baseline, and the improvement was particularly notable for independent external test sets when trained on small amounts of labeled data.

PLAIN LANGUAGE SUMMARY

Artificial intelligence requires extensive datasets with large amounts of annotated data from medical experts which can be difficult to acquire due to the large workload. To compensate for this, it is possible to utilize large amounts of un-annotated clinical data in addition to annotated data. However, this method has not been widely tested for the most common intracranial brain tumor, brain metastases. This study shows that this approach allows for data efficient deep learning models across multiple institutions with different clinical protocols and scanners.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

The Effectiveness of Afatinib as First-Line Treatment in Vietnamese Patients With EGFR-Mutant Non-Small Cell Lung Cancer and Brain Metastases

INTRODUCTION

The role of afatinib in the first-line treatment of EGFR-mutant advanced non-small cell lung cancer (NSCLC) patients has been proven through clinical trials and real-world studies. However, additional data on the effectiveness of afatinib in patients with brain metastases are lacking.

METHODS

EGFR-mutant NSCLC patients with brain metastases were retrospectively reviewed across nine cancer centers in Vietnam from April 1, 2018 to June 1, 2022. The primary endpoints included central nervous system progression-free survival (CNS-PFS) and overall survival (OS). The secondary endpoints were the objective response rate (ORR) and CNS-ORR.

RESULTS

Among 87 enrolled patients, 21.8%, 17.2%, and 60.9% received whole-brain radiation, gamma knife, and no locoregional therapy, respectively. With a median follow-up of 32.2 months for CNS-PFS and 35.3 months for OS, the median CNS-PFS and OS were 17.9 and 29.9 months, respectively. In multivariate analysis, patients receiving whole-brain radiation had significantly shorter CNS-PFS than those untreated with local therapy (16.1 vs. 22.6 months, p = 0.019), but not translating to an inferior OS. Furthermore, both the CNS-PFS and OS of patients with uncommon mutations were significantly worse than those of patients with Del19 (11.3 vs. 24.2 months, p = 0.013 and 17.7 vs. 34.0 months, p = 0.003, respectively). Univariate and multivariate analyses showed that a lower afatinib starting dose did not significantly affect CNS-PFS or OS. The CNS-ORR and ORR were 77.4% and 71.3%, respectively.

CONCLUSION

In our real-world study, afatinib showed encouraging effectiveness in Vietnamese patients with EGFR-mutant NSCLC and brain metastases at baseline.

A hybrid [18F]fluoropivalate PET-multiparametric MRI to detect and characterise brain tumour metastases based on a permissive environment for monocarboxylate transport

The incidence of Intracranial Metastatic Disease (IMD) continues to increase in part due to improvements in systemic therapy resulting in durable control of extra-cranial disease (ECD). Contrast-enhanced Magnetic Resonance Imaging (CE-MRI) is the preferred method for imaging IMD, but has limitations particularly in follow-up surveillance scans to optimise patient care. We investigate a new diagnostic approach of hybrid ([18]F]fluoropivalate (FPIA) Positron Emission Tomography-multiparametric MRI (PET-mpMRI), in 12 treatment-naïve and 10 stereotactic radiosurgery (SRS)-treated patients (± combination therapy within 4-8 weeks). High FPIA uptake was seen in all IMD compared to contralateral white matter, regardless of ECD tumour-of-origin (p = 0.0001) and FPIA-PET volumes extended beyond CE-MRI volumes in treatment-naïve but not SRS-treated tumours. Patients with maximum PET Standardised Uptake Value, (SUVmax) ≥ 2.0 showed particularly short overall-survival (median 4 v 15 months, p = 0.0136), while CE-MRI was uninformative regarding outcome; a PET-mpMRI grade-measure also provided non-invasive prediction of overall-survival, warranting larger studies of PET-mpMRI. Independent metabolomics analyses were consistent with shared adaptation of IMD to utilise or accumulate monocarboxylates and acylcarnitines, respectively, providing a common phenotypic basis to FPIA-PET. Reprogrammed monocarboxylate metabolism-related FPIA-PET provides new insights into annotating IMD, to be expounded in future opportunities for therapy decisions for the growing number of cancer patients with IMD [Trial registration reference: Clinicaltrials.gov NCT04807582; 3rd November 2021, retrospectively registered].

Multi-class brain malignant tumor diagnosis in magnetic resonance imaging using convolutional neural networks

Glioblastoma (GBM), primary central nervous system lymphoma (PCNSL), and brain metastases (BM) are common malignant brain tumors with similar radiological features, while the accurate and non-invasive dialgnosis is essential for selecting appropriate treatment plans. This study develops a deep learning model, FoTNet, to improve the automatic diagnosis accuracy of these tumors, particularly for the relatively rare PCNSL tumor. The model integrates a frequency-based channel attention layer and the focal loss to address the class imbalance issue caused by the limited samples of PCNSL. A multi-center MRI dataset was constructed by collecting and integrating data from Sir Run Run Shaw Hospital, along with public datasets from UPENN and TCGA. The dataset includes T1-weighted contrast-enhanced (T1-CE) MRI images from 58 GBM, 82 PCNSL, and 269 BM cases, which were divided into training and testing sets with a 5:2 ratio. FoTNet achieved a classification accuracy of 92.5 % and an average AUC of 0.9754 on the test set, significantly outperforming existing machine learning and deep learning methods in distinguishing among GBM, PCNSL, and BM. Through multiple validations, FoTNet has proven to be an effective and robust tool for accurately classifying these brain tumors, providing strong support for preoperative diagnosis and assisting clinicians in making more informed treatment decisions.

Incidental Brain Metastases From Prostate Cancer Diagnosed With PSMA PET/CT and MRI: A Case Series and Literature Review

BACKGROUND

Brain metastases (BMETS) from prostate cancer are rare. Hence, brain imaging in neurologically asymptomatic patients with advanced prostate cancer (aPC) is not routinely performed. Prostate-specific membrane antigen (PSMA) PET/CT uses a radiotracer that binds to prostate cancer epithelial cells and is FDA-approved for initial staging for high-risk prostate cancer, detecting prostate cancer recurrence, and determining eligibility for radionuclide therapy.

METHODS

We report six patients with asymptomatic BMETS from aPC found on staging PSMA PET/CT or MRI. Along with cranial MRI, PSMA PET/CT may be useful for detecting asymptomatic intracranial metastasis in select patients with prostate cancer.

RESULTS

Brain metastases were diagnosed in four patients by staging PSMA PET/CT scan-three after systemic disease progression and one during routine surveillance. In two other patients, BMETS were detected using MRI despite negative PSMA PET/CT for brain lesions. All were neurologically asymptomatic. Three patients had undetectable serum prostate-specific antigen (PSA) concentrations; one had neuroendocrine differentiation on histology.

CONCLUSION

In patients with poorly differentiated or neuroendocrine aPC, BMETS may occur without neurologic symptoms and stable PSA. PSMA PET/CT may complement brain MRI for identifying BMETS in these patients.

Epidemiology of adult brain tumors in the Philippine General Hospital from 2018 to 2022: Initial steps to a national brain tumor registry in a lower-middle income country

In the Philippines, there is a lack of epidemiological data on brain tumors due to the absence of a national registry. To bridge this gap, our team has set out to review histopathologically-confirmed brain tumor cases from 2018 to 2022 at the largest neurosurgical center in the country. 766 brain tumor cases were identified: 115 in 2018, 173 in 2019, 143 in 2020, 148 in 2021, and 187 in 2022. The crude incidences per year were 0.39, 0.58, 0.48, 0.50 and 0.66 per 100,000 from 2018 to 2022, respectively. The 5-year crude incidence rate was 2.58 per 100,000 persons. The five-year prevalence was 115.00, 266.00, 367.48, 456.39, and 566.30. Among patients, the mean age was 49 years old, with a male:female ratio of 2:3. Most cases were among the 51-60 age group (23.6 %). The most common types were meningioma (46 %) and gliomas, glioneuronal tumors, and neuronal tumors (23 %). Metastasis to the brain accounted for 6.5 % of all brain tumors. In our study, prevalence estimates were lower than globally-reported ones, likely due to its single-center nature. Tumor types approximated international reports, except for brain metastasis frequency. This initial work is a stepping stone for a future national brain tumor registry for the Philippines.

Immune cell infiltration into brain tumor microenvironment is mediated by Rab27-regulated vascular wall integrity

Aggressive brain tumors often exhibit immunologically 'cold' microenvironment, where the vascular barrier impedes effective immunotherapy in poorly understood ways. Tumor vasculature also plays a pivotal role in immunoregulation and antitumor immunity. Here, we show that small GTPase Rab27 controls the vascular morphogenesis and permeability for blood content and immune effectors. Thus, in Rab27a/b double knock out (Rab27-dKO) mice, the brain vasculature is abnormally scarce, while the blood vessels become dysmorphic and hyperpermeable in the context of brain tumors, including syngeneic glioblastoma. These defects are reflected in rearrangements of endothelial cell subpopulations with underlying diminution of venous endothelial subtype along with changes in gene and protein expression. Notably, Rab27-dKO brain endothelial cells exhibit deficient tight junctions, whereby they enable large-scale extravasation of cytotoxic T cells into the tumor mass. We show that Rab27-regulated vascular T cell infiltration can be exploited to enhance adoptive T cell therapy in syngeneic brain tumors.

Distinct characteristics of brain metastasis in lung adenocarcinoma: development of high-confidence cell lines

Lung cancer is a leading cause of cancer-related deaths worldwide, with brain metastasis occurring in approximately 30-55% of patients, particularly in lung adenocarcinoma. Due to the challenges in obtaining genuine brain metastasis tumor cells, researchers commonly use nude mouse models to establish brain metastasis cell lines, though traditional methods have limitations such as high costs, lengthy timeframes, and the need for specialized imaging equipment. To address these issues, we developed an improved approach by performing low cell number circulating intracranial injections (500-4000 cells) in nude mice, successfully establishing the H1975-BM1, BM2, and BM3 cell lines. Through RNA sequencing and bioinformatics analyses, we identified transcriptomic differences among these cell lines, revealing that H1975-BM1 cells primarily exhibit stem cell function and migration characteristics, while H1975-BM3 cells display enhanced chemotaxis, cell adhesion, and cytokine secretion associated with interactions. Experimental validation, including Transwell assays, CCK8, cell adhesion assays, and subcutaneous tumor implantation in nude mice, further confirmed these findings, with H1975-BM3 forming larger tumors and a more pronounced secretion cystic cavity. In conclusion, our improved methodology successfully established high-confidence brain metastasis lung adenocarcinoma cell lines, elucidating distinct transcriptomic and functional characteristics at different stages of brain metastasis progression.

Near-Infrared Photoimmunotherapy in Brain Tumors-An Unexplored Frontier

Near-infrared photoimmunotherapy (NIR-PIT) is a promising cancer treatment that uses near-infrared light to activate a conjugate of a monoclonal antibody (mAb) and a photoactivatable silica phthalocyanine dye (IRDye700DX: IR700). Unlike conventional photodynamic therapy (PDT), NIR-PIT selectively destroys targeted tumor cells while preserving the surrounding normal tissue and providing superior tissue penetration. Recently, NIR-PIT has been approved for the treatment of unresectable recurrent head and neck cancers in Japan. It induces highly selective cancer cell death; therefore, it is expected to be a new curative treatment option for various cancers, including brain tumors. In this review, we compare the principles of NIR-PIT and PDT and discuss the potential applications of NIR-PIT for brain tumors. We selected targetable proteins across various types of brain tumors and devised a strategy to effectively pass the mAb-IR700 conjugate through the blood-brain barrier (BBB), which is a significant challenge for NIR-PIT in treating brain tumors. Innovative approaches for delivering the mAb-IR700 conjugate across the BBB include exosomes, nanoparticle-based systems, and cell-penetrating peptides. Small-molecule compounds, such as affibodies, are anticipated to rapidly accumulate in tumors within intracranial models, and our preliminary experiments demonstrated rapid uptake. NIR-PIT also induces immunogenic cell death and activates the anti-tumor immune response. Overall, NIR-PIT is a promising approach for treating brain tumors. It has the potential to overcome the limitations of conventional therapies and offers new hope to patients with brain tumors.

Multiple deep learning models based on MRI images in discriminating glioblastoma from solitary brain metastases: a multicentre study

OBJECTIVE

Development of a deep learning model for accurate preoperative identification of glioblastoma and solitary brain metastases by combining multi-centre and multi-sequence magnetic resonance images and comparison of the performance of different deep learning models.

METHODS

Clinical data and MR images of a total of 236 patients with pathologically confirmed glioblastoma and single brain metastases were retrospectively collected from January 2019 to May 2024 at Provincial Hospital of Shandong First Medical University, and the data were randomly divided into a training set and a test set according to the ratio of 8:2, in which the training set contained 197 cases and the test set contained 39 cases; the images were preprocessed and labeled with the tumor regions. The images were pre-processed and labeled with tumor regions, and different MRI sequences were input individually or in combination to train the deep learning model 3D ResNet-18, and the optimal sequence combinations were obtained by five-fold cross-validation enhancement of the data inputs and training of the deep learning models 3D Vision Transformer (3D Vit), 3D DenseNet, and 3D VGG; the working characteristic curves (ROCs) of subjects were plotted, and the area under the curve (AUC) was calculated. The area under the curve (AUC), accuracy, precision, recall and F1 score were used to evaluate the discriminative performance of the models. In addition, 48 patients with glioblastoma and single brain metastases from January 2020 to December 2022 were collected from the Affiliated Cancer Hospital of Shandong First Medical University as an external test set to compare the discriminative performance, robustness and generalization ability of the four deep learning models.

RESULTS

In the comparison of the discriminative effect of different MRI sequences, the three sequence combinations of T1-CE, T2, and T2-Flair gained discriminative effect, with the accuracy and AUC values of 0.8718 and 0.9305, respectively; after the four deep learning models were inputted into the aforementioned sequence combinations, the accuracy and AUC of the external validation of the 3D ResNet-18 model were 0.8125, respectively, 0.8899, all of which are the highest among all models.

CONCLUSIONS

A combination of multi-sequence MR images and a deep learning model can efficiently identify glioblastoma and solitary brain metastases preoperatively, and the deep learning model 3D ResNet-18 has the highest efficacy in identifying the two types of tumours.

Unlocking the Role of Metabolic Pathways in Brain Metastatic Disease

The dissemination of malignant cells to the brain is a late-stage complication of cancer, leading to significant morbidity and mortality. Brain metastases (BM) affect 20-30% of cancer patients, primarily originating from lung cancer, breast cancer, and melanoma. Despite advances in molecular-targeted therapies, brain metastatic disease remains incurable, with a poor median survival of ≤12 months if left untreated. The lack of therapeutic efficacy is mainly attributed to the presence of the blood-brain barrier (BBB) and genetic differences between BM and their primary tumors. Previously published data have identified potential driver mutations of BM. However, the mechanisms underlying brain cancer dissemination remain unknown. Recent studies emphasize the pivotal role of metabolic adaptations in supporting the metastatic process, particularly in the nutrient-poor microenvironment characteristic of the brain. Understanding the interplay between metabolism and genetic alterations associated with brain metastatic disease could unveil novel therapeutic targets that are more effective in treating patients. This review focuses on relevant metabolic pathways in cancer, particularly brain cancer dissemination, while also presenting information on current preclinical models of BM, relevant clinical trials, and preclinical studies targeting metabolic reprogramming, providing an overview for advancing therapeutic strategies in BM.

New imaging findings of tumor invasion into brain tissue: "Peritumoral Hyperintense Enhancement Sign"

Introduction

This study investigated the MRI characteristics of meningiomas and brain metastases, exploring the relationship between the "Peritumoral Hyperintense Enhancement Sign" and brain invasion, and its clinical implications for treatment planning.

Methods

A multicenter retrospective analysis was conducted on 24 cases (17 brain metastases and 7 meningiomas), examining the MRI features of the "Peritumoral Hyperintense Enhancement Sign" and corresponding histopathological characteristics.

Results

All cases demonstrated peritumoral enhancement: 8 cases exhibited flame-shaped enhancement, 12 showed crescentic enhancement, and 4 displayed both patterns. Histopathological analysis confirmed brain invasion in regions showing abnormal enhancement.

Conclusion

The "Peritumoral Hyperintense Enhancement Sign" not only serves as a valuable indicator of brain invasion and provides guidance for clinical target delineation in treatment planning, but also facilitates more precise treatment planning and may contribute to improved prognostic assessment and reduced recurrence risk.

HER2-Positive Breast Cancer-Current Treatment Management and New Therapeutic Methods for Brain Metastasis

Background: Breast cancer can be classified based on the immunohistochemistry (IHC) phenotypes, defined by the presence or absence of the main IHC markers. IHC phenotyping is important as it determines the prognosis and guides treatment. For example, human epidermal growth factor receptor 2 (HER2) overexpression, which triggers cell growth and division, is observed in HER2-positive breast cancer. Methods: The standard treatment is based on trastuzumab plus pertuzumab in combination with taxane chemotherapy. The possibility of developing metastases depends on those phenotypes. Approximately 25-50% of patients with HER2-positive breast cancer experience brain metastases. This aspect is especially important, as 20% of those patients die as a result. Results: Through the years, many advanced therapies have been introduced to treat brain metastases, including whole brain radiotherapy, stereotactic radiosurgery, and a tyrosine kinase inhibitor (TKI), neratinib. Nonetheless, this still remains a therapeutic challenge. Conclusions: In this review, we focus on the treatment and efficiency of therapies targeting HER2-positive breast cancer, mainly concentrating on the current and newly developed treatment options for brain metastases, such as trastuzumab deruxtecan and tucatinib.

Exploring the Role of ADCs in Brain Metastases and Primary Brain Tumors: Insight and Future Directions

Primary and secondary brain tumors have always been a challenge due to their high morbidity and poor prognosis. The incidence of brain metastasis is also increasing with the advent of effective new treatments. Traditional systemic treatments have historically had limited success, partly due to poor central nervous system (CNS) penetration. However, the advent in recent decades of new therapies that have shown high encephalic response rates are challenging this paradigm. ADCs represent a new class of compounds revolutionizing cancer treatment with high systemic response rates and lower toxicities. The continuing evolution of ADCs has shown that certain structural features such as payload, linker, and drug-to-antibody ratio (DAR) are essential in determining their efficacy at the encephalic level, and some ADCs have started to exhibit promising efficacy in treating primary and secondary brain tumors. Unfortunately, most patients with untreated encephalic metastases are excluded from clinical trials, with data primarily from retrospective studies or post hoc analyses. This review describes the early signs of ADC efficacy in brain tumors, the role of complementary treatments like radiation therapy, and critical points to improve ADC efficacy in brain malignancies.

Immunotherapy in lung cancer brain metastases

Brain metastases (BM) occur frequently in lung cancer, particularly in non-small cell lung cancer (NSCLC) patients and remain a significant cause of morbidity and mortality. Standard therapies have limited efficacy due to poor crossing of the blood-brain barrier and the distinct features between BM and the primary tumor. This review explores the immune landscape of brain metastatic disease, emerging immunotherapeutic strategies, and promising biomarkers in NSCLC patients.

Identification and characterization of tertiary lymphoid structures in brain metastases

Brain metastases (BrM) are the most common cancers in the brain and linked to poor prognosis. Given the high incidence and often limited treatment options, understanding the complexity of the BrM tumor microenvironment is crucial for the development of novel therapeutic strategies. We performed transcriptome-wide gene expression profiling combined with spatial immune cell profiling to characterize the tumor immune microenvironment in 95 patients with BrM from different primary tumors. We found that BrM from lung carcinoma and malignant melanoma showed overall higher immune cell infiltration as compared to BrM from breast carcinoma. RNA sequencing-based immune cell deconvolution revealed gene expression signatures indicative of tertiary lymphoid structures (TLS) in subsets of BrM, mostly from lung cancer and melanoma. This finding was corroborated by multiplex immunofluorescence staining of immune cells in BrM tissue sections. Detection of TLS signatures was more common in treatment-naïve BrM and associated with prolonged survival after BrM diagnosis in lung cancer patients. Our findings highlight the cellular diversity of the tumor immune microenvironment in BrM of different cancer types and suggest a role of TLS formation for BrM patient outcome.

Role of Extracellular Vesicles in the Pathogenesis of Brain Metastasis

Extracellular vesicles (EVs) are small particles released by various cells, including cancer cells. They play a significant role in the development of different cancers, including brain metastasis. These EVs transport biomolecular materials such as RNA, DNA, and proteins from tumour cells to other cells, facilitating the spread of primary tumours to the brain tissue. EVs interact with the endothelial cells of the blood-brain barrier (BBB), compromising its integrity and allowing metastatic cells to pass through easily. Additionally, EVs interact with various cells in the brain's microenvironment, creating a conducive environment for incoming metastatic cells. They also influence the immune system within this premetastatic environment, promoting the growth of metastatic cells. This review paper focuses on the research regarding the role of EVs in the development of brain metastasis, including their impact on disrupting the BBB, preparing the premetastatic environment, and modulating the immune system. Furthermore, the paper discusses the potential of EVs as diagnostic and prognostic biomarkers for brain metastasis.

CD44 is a nexus between prognosis and therapeutics for brain cancer management

BACKGROUND

Brain tumors, both primary and metastatic, are the main cause of cancer-associated mortality leading to patients' poor quality-of-life that remain as a global challenge. This study aims to identify the hub molecular controlling brain cancer progression, and establish corresponding prognostic index and therapeutic modality for improved brain cancer management.

METHOD

We performed pan-cancer analysis unifying 9 publicly available datasets of cancers metastasized to the brain from different organs to identify the hub gene feasible for brain cancer prognosis. We conducted a series of computational analysis of the identified hub gene in primary gliomas to assess its diagnostic value. We investigated the potency and safety of cold atmospheric plasma (CAP) in treating brain cancers via targeting this hub molecule both in vitro and in vivo using glioma cells as the disease model.

RESULTS

We identified CD44 as the nexus of brain cancer prognosis and therapeutics that should be applicable to both primary and metastatic brain cancers. We, in addition, constructed a CD44-dependent unified index for brain cancer overall survival prognosis; and proposed CAP as a highly promising approach for arresting brain cancers via targeting CD44.

CONCLUSIONS

We are the first to characterize the relevance of CD44 with brain cancers by integrating its values on prognosis and therapeutics, as well as unifying its application scenarios in primary and metastatic brain cancers. Our work may spark innovative theranostic design for improved brain cancer management besides solutions provided by this study.

Stereotactic radiosurgery for patients with brain metastases: current principles, expanding indications and opportunities for multidisciplinary care

The management of brain metastases is challenging and should ideally be coordinated through a multidisciplinary approach. Stereotactic radiosurgery (SRS) has been the cornerstone of management for most patients with oligometastatic central nervous system involvement (one to four brain metastases), and several technological and therapeutic advances over the past decade have broadened the indications for SRS to include polymetastatic central nervous system involvement (>4 brain metastases), preoperative application and fractionated SRS, as well as combinatorial approaches with targeted therapy and immune-checkpoint inhibitors. For example, improved imaging and frameless head-immobilization technologies have facilitated fractionated SRS for large brain metastases or postsurgical cavities, or lesions in proximity to organs at risk. However, these opportunities come with new challenges and questions, including the implications of tumour histology as well as the role and sequencing of concurrent systemic treatments. In this Review, we discuss these advances and associated challenges in the context of ongoing clinical trials, with insights from a global group of experts, including recommendations for current clinical practice and future investigations. The updates provided herein are meaningful for all practitioners in clinical oncology.

Bayesian-Optimized Convolutional Neural Networks for Classifying Primary Tumor Origin of Brain Metastases from MRI

Background/Objectives: This study evaluates whether convolutional neural networks (CNNs) can be trained to determine the primary tumor origin from MRI images alone in patients with metastatic brain lesions. Methods: This retrospective, monocentric study involved the segmentation of 1175 brain lesions from MRI scans of 436 patients with histologically confirmed primary tumor origins. The four most common tumor types-lung adenocarcinoma, small cell lung cancer, breast cancer, and melanoma-were selected, and a class-balanced dataset was created through under-sampling. This resulted in 276 training datasets and 88 hold-out test datasets. Bayesian optimization was employed to determine the optimal CNN architecture, the most relevant imaging sequences, and whether the masking of images was necessary. We compared the performance of the CNN with that of two expert radiologists specializing in neuro-oncological imaging. Results: The best-performing CNN from the Bayesian optimization process used masked images across all available MRI sequences. It achieved Area-Under-the-Curve (AUC) values of 0.75 for melanoma, 0.65 for small cell lung cancer, 0.64 for breast cancer, and 0.57 for lung adenocarcinoma. Masked images likely improved performance by focusing the CNN on relevant regions and reducing noise from surrounding tissues. In comparison, Radiologist 1 achieved AUCs of 0.55, 0.52, 0.45, and 0.51, and Radiologist 2 achieved AUCs of 0.68, 0.55, 0.64, and 0.43 for the same tumor types, respectively. The CNN consistently showed higher accuracy, particularly for melanoma and breast cancer. Conclusions: Bayesian optimization enabled the creation of a CNN that outperformed expert radiologists in classifying the primary tumor origin of brain metastases from MRI.

Long non-coding RNA CYTOR promotes the progression of melanoma via the miR-485-5p/GPI axis

Background

Recent research has underscored the critical role of long non-coding RNAs (lncRNAs) in tumorigenesis and malignancy development. Nevertheless, the role of lncRNA cytoskeleton regulator RNA (CYTOR) in the progression of melanoma remains only partially elucidated. This research seeks to explore the impact of CYTOR on melanoma development and to elucidate the molecular mechanisms involved.

Methods

In vitro and in vivo models were used to assess CYTOR expression levels by QPCR and Western blotting. Melanoma cell proliferation, migration, and invasion were assessed by CCK-8 assay, scratch wound assay and transwell invasion experiments. The mechanism of CYTOR promoting melanoma progression was verified in a xenograft tumor mouse model.

Results

Our investigation identified a marked increase in CYTOR expression levels in both melanoma tissues and cells. Experiments conducted both in vitro and in vivo revealed that CYTOR markedly stimulated melanoma cell proliferation, migration, and invasion. Dual-luciferase reporter assays confirmed the direct binding of miR-485-5p to CYTOR, and glucose-6-phosphate isomerase (GPI) was identified as a direct target of miR-485-5p.

Phase 2 trial of perioperative chemo-immunotherapy for gastro-esophageal adenocarcinoma: The role of M2 macrophage landscape in predicting response

We present the clinical results of a phase 2 trial combining neoadjuvant docetaxel, cisplatin, 5 Flourouracil, and the PD-L1 inhibitor avelumab in locally advanced gastro-esophageal adenocarcinoma (GEA). Fifty-one patients receive neoadjuvant therapy with 50 proceeding to surgery. Grade 3-4 adverse events occur in 40%; complete/major pathological response is found in 7/50 (14%) and 9/50 (18%), with 2-year disease-free survival of 67.5%. There is no correlation between tumor regression and PD-L1 or mismatch repair (MMR) status. Multiplex immunohistochemistry and longitudinal single-cell transcriptomic profiling reveal alterations in certain innate immune cell populations, particularly noting an M2-tumor-associated macrophage (M2-TAM) proliferation in non-responding tumors. These findings describe the effective nature of this treatment regimen for GEA and reveal associated features of the inflammatory milieux associated with response to chemo-immunotherapy. The specific character of the inflammatory environment in non-responders may, in the future, help personalize treatment. This study was registered at ClinicalTrials.gov (NCT03288350).

Four-gene Prognostic Signature and Risk of Brain Metastasis of Lung Adenocarcinoma

Brain metastasis has a high incidence and poor prognosis in lung adenocarcinoma (LUAD). We sought to identify genes associated with LUAD brain metastasis and with the prognosis of patients with LUAD. Differential gene expression analysis was performed on LUAD patients with and without distant metastasis from the Cancer Genome Atlas (TCGA) database and LUAD patients with and without brain metastasis from the GEO GSE14108 and GSE10072 data sets. Subsequently, a LASSO model was constructed using the genes differentially expressed in both analyses to screen for prognostic genes. A risk model based on 11 genes was established by screening prognostic genes. Subsequently, a prognostic prediction model was developed based on the risk model. Expression and survival analysis of the identified genes in metastatic LUAD was assessed. As a result, differential gene expression analysis indicated that compared to primary lung cancer, the expression of CMAS, NEK2, and SHCBP1 was significantly upregulated in metastatic lung cancer, whereas the expression of IL2 was significantly downregulated. Additionally, these genes exhibited strong correlations with the overall survival of LUAD patients. Finally, compared with LUAD patients without brain metastasis, immunohistochemistry analysis verified CMAS, NEK2, and SHCBP1 exhibited increased expression in LUAD with brain metastasis.

A new, immunocompetent brain-metastatic mouse model of HER2-positive breast cancer

Brain metastasis is a common and devastating complication of cancer that affects over 50% of HER2-positive (HER2+) breast cancer patients. The lack of effective long-term treatment options for brain metastasis significantly increases morbidity and mortality among these patients. Therefore, understanding the underlying mechanisms that drive brain metastasis is critically important for developing new strategies to treat it effectively. Genetically engineered mouse models (GEMMs) of HER2+ breast cancer have been instrumental in understanding the development and progression of HER2+ breast cancer. However, the GEMM models for HER2+ breast cancer do not develop brain metastasis and are not suitable for the study of brain metastasis. We therefore developed a fully immunocompetent mouse model of experimental brain metastasis in HER2+ breast cancer by injecting a murine HER2/neu-expressing mammary-tumor-cell line into the arterial circulation of syngeneic FVB/N mice followed by isolation of brain-metastatic derivatives through in-vivo selection. By this in-vivo serial passaging process, we selected highly brain-metastatic (BrM) derivatives known as neu-BrM. Notably, after intracardiac injection, neu-BrM cells generated brain metastasis in 100% of the mice, allowing us to study the later stages of metastatic progression, including cancer-cell extravasation and outgrowth in the brain. Analogous to human brain metastasis, we observed reactive gliosis and significant immune infiltration in the brain tissue of mice injected with neu-BrM cells. We further confirmed that brain-metastatic lesions in the neu-BrM model express HER2. Consistently, we found that the brain-metastatic burden in these mice can be significantly reduced but not eliminated with tucatinib, an FDA-approved, blood-brain-barrier-penetrant HER2 inhibitor. Therefore, the neu-BrM HER2+ breast cancer model can be used to investigate the roles of innate and adaptive immune-system components during brain-metastatic progression and the mechanisms of HER2-therapy response and resistance.

Targeting SCD triggers lipotoxicity of cancer cells and enhances anti-tumor immunity in breast cancer brain metastasis mouse models

Breast cancer brain metastases (BCBM) are incurable, and new therapies are urgently needed. BCBM upregulates stearoyl-CoA desaturase (SCD), an enzyme that catalyzes the synthesis of monounsaturated fatty acids, suggesting a potential metabolic vulnerability. Here, we test the effect of a brain-penetrant, clinical-stage SCD inhibitor (SCDi) on breast cancer cells and mouse models of BCBM. We show that SCDi markedly reshapes the lipidome of breast cancer cells, resulting in endoplasmic reticulum stress, DNA damage, impaired DNA damage repair, and cytotoxicity. Importantly, SCDi alone or combined with a PARP inhibitor prolongs the survival of BCBM-bearing mice. Furthermore, pharmacological inhibition of SCD enhances antigen presentation by dendritic cells, increases interferon signaling, promotes the infiltration of cytotoxic T cells, and decreases the proportion of exhausted T cells and regulatory T cells (Tregs) in the tumor microenvironment (TME) in a syngeneic mouse model of BCBM. Additionally, SCDi reduces the engagement of immunosuppressive pathways, including the PD-1:PD-L1/PD-L2 and PVR/TIGIT axes in the TME. These findings suggest that SCD inhibition could be an effective strategy to both intrinsically reduce tumor growth and reprogram anti-tumor immunity in the brain microenvironment to treat BCBM.

Individualized patient tumor organoids faithfully preserve human brain tumor ecosystems and predict patient response to therapy

Tumor organoids are important tools for cancer research, but current models have drawbacks that limit their applications for predicting response to therapy. Here, we developed a fast, efficient, and complex culture system (IPTO, individualized patient tumor organoid) that accurately recapitulates the cellular and molecular pathology of human brain tumors. Patient-derived tumor explants were cultured in induced pluripotent stem cell (iPSC)-derived cerebral organoids, thus enabling culture of a wide range of human tumors in the central nervous system (CNS), including adult, pediatric, and metastatic brain cancers. Histopathological, genomic, epigenomic, and single-cell RNA sequencing (scRNA-seq) analyses demonstrated that the IPTO model recapitulates cellular heterogeneity and molecular features of original tumors. Crucially, we showed that the IPTO model predicts patient-specific drug responses, including resistance mechanisms, in a prospective patient cohort. Collectively, the IPTO model represents a major breakthrough in preclinical modeling of human cancers, which provides a path toward personalized cancer therapy.

Breast Cancer Brain Metastases: A Neurosurgical Point of View From a Single-Center Experience

BACKGROUND

Brain metastases represent an important factor in breast cancer morbidity and mortality. Although various therapeutic options improved these patients' outcomes, the incidence of this disease is still rising. Several molecular subtypes of breast cancer have been studied, and human epidermal growth factor receptor 2 (HER2) positive and triple-negative breast cancer (TNBC) are more frequently associated with brain metastases. Therefore, anti-HER2 agents have been developed and studied, and they have shown promising results. Nevertheless, in patients with breast cancer brain metastases and acute neurological aggravation, neurosurgery is the primary option and the only one that can immediately reverse the symptoms. In the long run, a multimodal approach involving neurosurgical intervention can positively impact the prognosis.

MATERIAL AND METHODS

Patients with a confirmed diagnosis of brain metastases from breast cancer (BMBC) between January 2013 and December 2023 were retrospectively reviewed. All patients were newly diagnosed and treated in the 3rd Neurosurgical Department at the Clinical Emergency Hospital, "Bagdasar-Arseni" in Bucharest, Romania. Statistical analyses were carried out and interpreted accordingly.

RESULTS

The study analyzed 62 patients with BMBC. The median age at diagnosis was 57.19 years, and the most frequently encountered symptoms were represented by headaches, raised intracranial pressure syndrome, and motor deficits. More than 80% of the patients had a Karnofsky Performance Status (KPS) between 80 and 100, and the most associated comorbidities were cardiovascular and type 2 diabetes mellitus. A total of 88.70% of the patients had a single brain metastasis, and the most common localizations were the posterior fossa/cerebellum and frontal lobe. Gross-total resection was possible in 79.03% of the cases, while complications were recorded in 8.06%. Better survival rates were registered in patients of younger ages, with higher KPS, single BM, and smaller tumoral volumes, treated by gross-total resection and by a multimodal approach.

CONCLUSIONS

Notwithstanding significant advancements in the field of breast cancer, the prognosis of patients with brain metastases remains poor. However, a multimodal approach can prolong survival rates and improve outcomes, while in patients with acute clinical manifestations, neurosurgery remains the only immediate option to reverse the symptoms.

Indoleamine 2,3-dioxygenase 1-mediated immune suppressive status is positively associated with brain metastasis in patients with non-small cell lung cancer

Background

Indoleamine 2,3-dioxygenase (IDO1) activity, measured by kynurenine/tryptophan (K:T) ratio, is known for its association with distant metastasis and overall survival (OS) in patients with non-small cell lung cancer (NSCLC). Here, we aimed to examine whether IDO1 activity is correlated with OS in NSCLC patients with brain metastasis (Bramet) and has negative effect on modulating the anti-tumor functions of immune cells.

Methods

This study was a part of a prospective clinical trial in circulating biomarkers. Blood or tissues from eligible participants were collected for measurement of kynurenine, tryptophan, immune cell subtype, scRNA-seq analysis, and untargeted metabolomics analysis.

Results

A total of 195 patients were enrolled. The median kynurenine to tryptophan (K:T) ratio was 0.18, with consistent values observed among patients with NSCLC Bramet and those without (0.18 and 0.11, respectively). Notably, student's t-test analysis revealed significantly higher kynurenine concentrations in stage IV patients compared to those in stage I (2.3 vs 1.7 µM, P < 0.001). In patients with Bramet, both kynurenine concentrations and K:T ratios were significantly elevated in comparison with those of extra-cerebral metastasis (2.7 vs 1.9 µM, P < 0.001; 0.12 vs 0.095, P = 0.028; respectively). Single-cell analysis further validated a high level of IDO1 expression in stage IV tumors or Bramet lesions, particularly in macrophages, regulated by chemokines such as CXCL11. Additionally, K:T ratios exhibited significant associations with Treg cell percentages and OS in patients with Bramet (P = 0.039). Treatment with kynurenine led to the upregulation of immune-suppressive molecules, including PD-1, in T cells. Finally, untargeted metabolomics analysis further identified that, apart from the IDO1 metabolic pathway, other metabolites, such as those involved in phospholipid pathways, were also implicated in Bramet.

Conclusion

IDO1 metabolites may play immune-suppressive roles in NSCLC patients with Bramet.

Single-cell and spatial genomic landscape of non-small cell lung cancer brain metastases

Brain metastases frequently develop in patients with non-small cell lung cancer (NSCLC) and are a common cause of cancer-related deaths, yet our understanding of the underlying human biology is limited. Here we performed multimodal single-nucleus RNA and T cell receptor, single-cell spatial and whole-genome sequencing of brain metastases and primary tumors of patients with treatment-naive NSCLC. Chromosomal instability (CIN) is a distinguishing genomic feature of brain metastases compared with primary tumors, which we validated through integrated analysis of molecular profiling and clinical data in 4,869 independent patients, and a new cohort of 12,275 patients with NSCLC. Unbiased analyses revealed transcriptional neural-like programs that strongly enriched in cancer cells from brain metastases, including a recurring, CINhigh cell subpopulation that preexists in primary tumors but strongly enriched in brain metastases, which was also recovered in matched single-cell spatial transcriptomics. Using multiplexed immunofluorescence in an independent cohort of treatment-naive pairs of primary tumors and brain metastases from the same patients with NSCLC, we validated genomic and tumor-microenvironmental findings and identified a cancer cell population characterized by neural features strongly enriched in brain metastases. This comprehensive analysis provides insights into human NSCLC brain metastasis biology and serves as an important resource for additional discovery.

Neurological Manifestations of Patients With CNS Metastases: Experience From a Single Center in an Upper-Middle-Income Country

PURPOSE

This study aimed to report the neurological manifestations of patients with CNS metastases (CNSm) and to determine their association with survival in patients with brain metastases (BrMs).

MATERIALS AND METHODS

A retrospective analysis of patients with CNSms (BrMs or neoplastic meningitis) seen at two referral centers between 2010 and 2022. The neurological manifestations and their association with survival were measured and presented.

RESULTS

Among 822 patients with CNSms, the most common neurological manifestations were headache, focal weakness, visual disorders, nausea/vomiting, seizures, and altered mental status (53%, 35%, 24%, 23%, 22%, and 18%, respectively). In patients with BrMs, neurological manifestations associated with survival were asymptomatic (hazard ratio [HR], 0.48 [95% CI, 0.31 to 0.73]; P = .001), focal weakness (HR, 1.26 [95% CI, 1.02 to 1.54]; P = .027), or visual disorders (HR, 1.26 [95% CI, 1.01 to 1.58]; P = .045).

CONCLUSION

Neurological manifestations in patients with BrMs are associated with survival and can aid in prognostic stratification.

Symptom Clusters in Patients with Brain Tumors: A Systematic Review

OBJECTIVES

To identify composition, predictors, outcomes and stability of symptom clusters in brain tumor patients and to examine assessment tools and statistical methods.

METHODS

The PubMed, Web of Science, Embase, CINAHL, and Cochrane Library databases were systematically searched. Two reviewers independently screened the titles, abstracts and full texts. Data were extracted and synthesized based on the aims of the review.

RESULTS

Eleven studies were included, covering eight symptom assessment tools and four analysis methods. Four symptom clusters in patients with primary brain tumors were identified: lack of energy cluster/ affective cluster/ gastrointestinal cluster/ neurocognitive cluster. Three symptom clusters in patients with brain metastases were identified: somatic stress cluster/ gastrointestinal cluster/ neurocognitive cluster. Longitudinal instability of symptom clusters was found. The severity of symptom clusters has a significant negative correlation with quality of life, performance status and functioning. There is little information on the predictors.

CONCLUSIONS

Although major symptom clusters of patients with primary brain tumors and brain metastases have been identified, methodological differences have affected the homogeneity of the inferences drawn. It is necessary to standardize the selection of assessment tools and statistical methods for symptom cluster research to facilitate comparison and combination across studies, and further clarify the temporal trajectories, predictive factors, and underlying mechanisms.

IMPLICATIONS FOR NURSING PRACTICE

Knowledge of symptom clusters contributes to the adoption of prevention strategies and management measures and the adjustment of treatments, thus alleviating symptom distress and improving quality of life.

A 3D Convolutional Neural Network Based on Non-enhanced Brain CT to Identify Patients with Brain Metastases

Dedicated brain imaging for cancer patients is seldom recommended in the absence of symptoms. There is increasing availability of non-enhanced CT (NE-CT) of the brain, mainly owing to a wider utilization of Positron Emission Tomography-CT (PET-CT) in cancer staging. Brain metastases (BM) are often hard to diagnose on NE-CT. This work aims to develop a 3D Convolutional Neural Network (3D-CNN) based on brain NE-CT to distinguish patients with and without BM. We retrospectively included NE-CT scans for 100 patients with single or multiple BM and 100 patients without brain imaging abnormalities. Patients whose largest lesion was < 5 mm were excluded. The largest tumor was manually segmented on a matched contrast-enhanced T1 weighted Magnetic Resonance Imaging (MRI), and shape radiomics were extracted to determine the size and volume of the lesion. The brain was automatically segmented, and masked images were normalized and resampled. The dataset was split into training (70%) and validation (30%) sets. Multiple versions of a 3D-CNN were developed, and the best model was selected based on accuracy (ACC) on the validation set. The median largest tumor Maximum-3D-Diameter was 2.29 cm, and its median volume was 2.81 cc. Solitary BM were found in 27% of the patients, while 49% had > 5 BMs. The best model consisted of 4 convolutional layers with 3D average pooling layers, dropout layers of 50%, and a sigmoid activation function. Mean validation ACC was 0.983 (SD: 0.020) and mean area under receiver-operating characteristic curve was 0.983 (SD: 0.023). Sensitivity was 0.983 (SD: 0.020). We developed an accurate 3D-CNN based on brain NE-CT to differentiate between patients with and without BM. The model merits further external validation.

Predictive Factors for Oligometastatic Renal Cell Carcinoma Treated with Stereotactic Radiation: A Retrospective Study

BACKGROUND AND OBJECTIVE

Stereotactic ablative radiotherapy (SAbR) has shown promise in controlling oligometastatic renal cell carcinoma (omRCC). Careful patient selection is critical, and yet the selection criteria remain unknown for patients who will not be harmed by delayed systemic therapy using SAbR. Here, we analyzed long-term follow-up of omRCC patients treated with SAbR to derive the predictors of survival benefit.

METHODS

We retrospectively reviewed patients with up to five omRCC sites treated with sequential SAbR from November 2007 to July 2022. Overall survival (OS), progression-free survival (PFS), local control (LC), and toxicity were analyzed. The predictors of PFS were analyzed using a univariate analysis and a Cox proportional hazard (CPH) model-based machine learning approach.

KEY FINDINGS AND LIMITATIONS

We analyzed 153 patients who underwent SAbR to 337 metastases with a median follow-up of 27 mo. The median OS and PFS were 61.3 and 32 mo, respectively. The rate of grade ≥3 toxicity was 1.3%, and the 3-yr rate of LC was 98%. Patients with bone and brain metastases had lower PFS on the univariate analysis. When compared with historical controls, the delayed-onset PFS with first-line systemic therapy in this cohort was not compromised. The CPH model found bone, brain, and number of metastases at diagnosis to be the predictors of PFS, with a C-index of 0.66 and 1-yr area under the curve of 0.68.

CONCLUSIONS AND CLINICAL IMPLICATIONS

For selected patients, SAbR is effective in controlling omRCC for >2 yr and can delay systemic therapy without compromising patient outcome. Bone and brain metastases, as well as an increasing number of metastases are poor predictive factors for omRCC patients treated with sequential SAbR who may benefit from upfront systemic therapy. Prospective studies are required to verify these findings.

An in vivo screen identifies NAT10 as a master regulator of brain metastasis

Emerging evidence has shown that epigenetic regulation plays a fundamental role in cancer metastasis, the major cause of cancer-related deaths. Here, we conducted an in vivo screen for vulnerabilities of brain metastasis and identified N-acetyltransferase 10 (NAT10) as a driver of brain metastasis. Knockdown of NAT10 restrains cancer cell proliferation and migration in vitro and tumor growth and brain metastasis in vivo. The poorly characterized RNA helicase domain of NAT10 is critical for cell growth in vitro, while both RNA helicase and NAT domains are essential for primary tumor growth and brain metastasis in vivo. Mechanically, NAT10 promotes the expression of 3-phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase 1 (PSAT1), two enzymes for serine biosynthesis implicated in brain metastasis. Silencing PHGDH or PSAT1 in metastatic breast cancer cells inhibits their growth in the serine/glycine-limited condition, phenocopying the effects of NAT10 depletion. These findings establish NAT10 as a key regulator of brain metastasis and nominate NAT10 as a target for treating metastasis.

Distinct 5-methylcytosine profiles of LncRNA in breast cancer brain metastasis

BACKGROUND

Recent studies have identified a complex relationship between methylation patterns and the development of various cancers. Breast cancer (BC) is the second leading cause of cancer mortality among women. Approximately 5-20% of BC patients are at risk of BC brain metastases (BCBM). Although 5-methylcytosine (m5C) has been identified as an important regulatory modifier, its distribution in BCBM is not well understood. This study aimed to investigate the distribution of m5C in BCBM.

MATERIALS AND METHODS

Samples from BCBM (231-BR cells) and BC (MDA-MB-231 cells) groups were subjected to a comprehensive analysis of the m5C methylation in long non-coding RNA (lncRNA) using methylated RNA immunoprecipitation next-generation sequencing (MeRIP-seq). The expression levels of methylated genes in BC and adjacent tissues were verified through quantitative real-time polymerase chain reaction (RT-qPCR). Enrichment pathway analyses were through Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) to predict the potential functions of m5C in BCBM.

RESULTS

The MeRIP-seq analysis identified 23,934 m5C peaks in BCBM and 21,236 m5C in BC. A total of 9,480 annotated genes (BCBM) and 8,481 annotated genes (BC) were mapped. Notably, 1,819 methylation sites in lncRNA were upregulated in BCBM, whereas 2,415 methylation sites were upregulated in BC. Significant m5C hypermethylated lncRNAs included ENST00000477316, ENST00000478098 and uc002gtt.1, whereas hypomethylated lncRNAs included ENST00000600912, ENST00000493668, ENST00000544651 and ENST00000464989. These results were verified by qPCR and MeRIP-qPCR in BC and BCBM. Considering the strong association between m5C RNA methylation regulators and lncRNA, we examined the expression levels of 13 m5C RNA methylation regulators and observed significant differences between BC tissues and adjacent normal tissues. In addition, the interaction between regulators of altered expression and the differentially expressed genes in vitro was analyzed. The GO and KEGG pathways analyses revealed that genes significantly associated with m5C sites in lncRNA were linked to the BCBM signaling pathways.

CONCLUSION

This uncovered significant variations in the levels and distribution of m5C in BCBM compared to BC. The findings provide a new theoretical understanding of the mechanisms of BCBM.

A Practical, Short, [18F]F-DOPA PET/CT Acquisition Method for Distinguishing Recurrent Brain Metastases from Radionecrosis Following Radiotherapy

Background/Objectives: Determining whether 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine positron emission tomography/computed tomography ([18F]F-DOPA PET/CT) data indicate brain metastasis progression (MP) or brain radionecrosis (RN) is challenging. The aim of this study was to present a method usable in the clinical setting without dedicated software that relies on less than five minutes of SiPM PET/CT data collected immediately after [18F]F-DOPA injection. Methods: We prospectively enrolled 15 patients with 19 lesions. Each acquisition was conducted in list mode (LM) for 25 min using a four-ring SiPM PET/CT system. We reconstructed three volumes from the LM file: acquisition duration of 120 s (V120), 270 s (V270), and 10 min for the standard clinical volume (Vclin). We measured each lesion's maximum voxel activity (LSmax) and the corresponding mean activity with its standard deviation (CLmean, CLsd). We then calculated the LSmax/CLmean ratio and the coefficient of variation (COV), defined as 100 × (CLsd/CLmean). Results: Lesions were classified as RN (n = 7) and MP (n = 12). For all volumes, LSmax/CLmean differed significantly. The COV parameter exhibited significant differences in all comparisons except for V120 vs. V270. The best diagnostic performances were observed for V120 and V270, with an accuracy of 94.7%. The AUC values were 97.6% in both cases. Conclusions: A simple, static [18F]F-DOPA PET/CT acquisition, starting 1.5 min after injection and lasting less than five minutes, permitted reaching excellent diagnostic performance (100% sensitivity, 91.7% specificity, and 97.6% AUC) in discriminating between RN and MP.

Protocol for generating brain metastatic tumor cells through repeated intracardiac injections in mice

Here, we present a protocol for generating the lung cancer cell line, LLC1-BMT5, with highly brain metastatic tropism through multiple rounds of in vivo selection. We describe steps for establishing the brain metastases (BrMs) mouse model through intracardiac injection of cancer cells. We then detail procedures for obtaining brain metastatic subpopulations, in vivo selection of LLC1-BMT5 cells, and validating metastatic potential. This protocol will facilitate the study of the molecular mechanisms of BrMs and the development of anti-BrM treatment strategies. For complete details on the use and execution of this protocol, please refer to Wang et al.1.

A Cost-Effective and Easy to Assemble 3D Human Microchannel Blood-Brain Barrier Model and Its Application in Tumor Cell Adhesion Under Flow

By utilizing polydimethylsiloxane (PDMS), collagen hydrogel, and a cell line for human cerebral microvascular endothelial cells, we produced a 3D microchannel blood-brain barrier (BBB) model under physiological flow. This 3D BBB has a circular-shaped cross-section and a diameter of ~100 μm, which can properly mimic the cerebral microvessel responsible for material exchange between the circulating blood and brain tissue. The permeability of the 3D microchannel BBB to a small molecule (sodium fluorescein with a molecular weight of 376) and that to a large molecule (Dex-70k) are the same as those of rat cerebral microvessels. This 3D BBB model can replicate the effects of a plasma protein, orosomucoid, a cytokine, vascular endothelial growth factor (VEGF), and an enzyme, heparinase III, on either rat cerebral or mesenteric microvessesels in terms of permeability and the modulation of glycocalyx (heparan sulfate). It can also replicate the adhesion of a breast cancer cell, MDA-MB-231, in rat mesenteric microvessels under no treatment or treatments with VEGF, orosomucoid, and heparinase III. Because of difficulties in accessing human cerebral microvessels, this inexpensive and easy to assemble 3D human BBB model can be applied to investigate BBB-modulating mechanisms in health and in disease and to develop therapeutic interventions targeting tumor metastasis to the brain.

A novel optimized orthotopic mouse model for brain metastasis with sustained cerebral blood circulation and capability of multiple delivery

Brain metastasis is thought to be related to the high mortality and poor prognosis of lung cancer. Despite significant advances in the treatment of primary lung cancer, the unique microenvironment of the brain renders current therapeutic strategies largely ineffective against brain metastasis. The lack of effective drugs for brain metastasis treatment is primarily due to the incomplete understanding of the mechanisms underlying its initiation and progression. Currently, our understanding of brain metastasis remains limited, primarily due to the absence of appropriate models that can realistically simulate the entire process of tumor cell detachment from the primary site, circulation through the bloodstream, and eventual colonization of the brain. Therefore, there is a pressing need to develop more suitable lung cancer brain metastasis models that can effectively replicate these critical stages of metastasis. Here, based on the traditional carotid artery injection model, we established a novel orthotopic mouse model by using a light-controlled hydrogel to repair the puncture site on the carotid artery, with sustained cerebral blood circulation and the capability of multiple delivery cancer cell to mimic lung cancer brain metastasis. The optimized orthotopic mouse model significantly reduced cerebral ischemia and improved cerebral oxygenation by 60% compared to the traditional orthotopic mouse model, enhancing post-operative survival rates. It also showed a reduction in pro-inflammatory cytokines and featured less inflammatory and more resting states of microglial and astrocyte cells. Furthermore, the optimized orthotopic mouse model markedly increased the success rate and absolute number of the metastatic clones in the brain. Additionally, the multiple delivery model based on the optimized orthotopic mouse model substantially augmented the tumor clone number and formation rates compared to single injection in the optimized orthotopic mouse model. This model overcomes previous limitations by maintaining cerebral circulation, providing a more accurate simulation of the continuous entry of tumor cells into cerebral circulation. It offers a robust platform for studying the interactions of cancer cells with the brain microenvironment and testing new therapeutic approaches.

Revealing shared molecular drivers of brain metastases from distinct primary tumors

Brain metastasis is the most common type of brain cancer, associated with significant neurological dysfunction and a poor prognosis. We investigated the transcriptome of 128,421 single-cells of 36 brain metastases, originating from a variety of primary tumors, including melanoma, breast, lung, ovarian, colorectal, and renal cancers. Our aim was to identify common molecular factors across these tumors, shedding light on key interactions that facilitate tumor establishment in the brain. We specifically focused on the dynamics of the blood-tumor barrier and its effects on endothelial cells, pericytes, and astrocytes. Our analysis decoded complex cell-cell communications, emphasizing the crucial role of astrocytes in the tumor microenvironment (TME). This provided insights into how these interactions impact the permeability of the blood-tumor barrier and contribute to the development of brain metastases. We identified the VEGFA, SEMA3, and SPP1 pathways as key regulators in brain metastasis, affecting vascular permeability and cellular dynamics. Spatial transcriptome analysis confirmed our findings and linked these pathways to TME enrichment. The pronounced expression of VEGFA by cancer cells suggests a significant activation of angiogenic pathways, influencing vascular responses and the intricate architecture of brain tissue. The interplay of these signaling pathways underlines the complexity of molecular interactions that define the microenvironment of brain metastases.

Bridging the gap: unlocking the potential of emerging drug therapies for brain metastasis

Brain metastasis remains an unmet clinical need in advanced cancers with an increasing incidence and poor prognosis. The limited response to various treatments is mainly derived from the presence of the substantive barrier, blood-brain barrier (BBB) and brain-tumour barrier (BTB), which hinders the access of potentially effective therapeutics to the metastatic tumour of the brain. Recently, the understanding of the structural and molecular features of the BBB/BTB has led to the development of efficient strategies to enhance BBB/BTB permeability and deliver drugs across the BBB/BTB to elicit the anti-tumour response against brain metastasis. Meanwhile, novel agents capable of penetrating the BBB have rapidly developed and been evaluated in preclinical studies and clinical trials, with both targeted therapies and immunotherapies demonstrating impressive intracranial activity against brain metastasis. In this review, we summarize the recent advances in the biological properties of the BBB/BTB and the emerging strategies for BBB/BTB permeabilization and drug delivery across the BBB/BTB. We also discuss the emerging targeted therapies and immunotherapies against brain metastasis tested in clinical trials. Additionally, we provide our viewpoints on accelerating clinical translation of novel drugs into clinic for patients of brain metastasis. Although still challenging, we expect this review to benefit the future development of novel therapeutics, specifically from a clinical perspective.

Nanophotonic-enhanced photoacoustic imaging for brain tumor detection

Photoacoustic brain imaging (PABI) has emerged as a promising biomedical imaging modality, combining high contrast of optical imaging with deep tissue penetration of ultrasound imaging. This review explores the application of photoacoustic imaging in brain tumor imaging, highlighting the synergy between nanomaterials and state of the art optical techniques to achieve high-resolution imaging of deeper brain tissues. PABI leverages the photoacoustic effect, where absorbed light energy causes thermoelastic expansion, generating ultrasound waves that are detected and converted into images. This technique enables precise diagnosis, therapy monitoring, and enhanced clinical screening, specifically in the management of complex diseases such as breast cancer, lymphatic disorder, and neurological conditions. Despite integration of photoacoustic agents and ultrasound radiation, providing a comprehensive overview of current methodologies, major obstacles in brain tumor treatment, and future directions for improving diagnostic and therapeutic outcomes. The review underscores the significance of PABI as a robust research tool and medical method, with the potential to revolutionize brain disease diagnosis and treatment.

Molecular Underpinnings of Brain Metastases

Brain metastases are the most commonly diagnosed type of central nervous system tumor, yet the mechanisms of their occurrence are still widely unknown. Lung cancer, breast cancer, and melanoma are the most common etiologies, but renal and colorectal cancers have also been described as metastasizing to the brain. Regardless of their origin, there are common mechanisms for progression to all types of brain metastases, such as the creation of a suitable tumor microenvironment in the brain, priming of tumor cells, adaptations to survive spreading in lymphatic and blood vessels, and development of mechanisms to penetrate the blood-brain barrier. However, there are complex genetic and molecular interactions that are specific to every type of primary tumor, making the understanding of the metastatic progression of tumors to the brain a challenging field of study. In this review, we aim to summarize current knowledge on the pathophysiology of brain metastases, from specific genetic characteristics of commonly metastatic tumors to the molecular and cellular mechanisms involved in progression to the central nervous system. We also briefly discuss current challenges in targeted therapies for brain metastases and how there is still a gap in knowledge that needs to be overcome to improve patient outcomes.

A Site-Specific MiniAp4-Trastuzumab Conjugate Prevents Brain Metastasis

Monoclonal antibodies (mAbs) are changing cancer treatments. However, the presence of the blood-brain barrier (BBB) and the blood-tumor barrier (BTB) limits the use of mAbs to treat brain cancer or brain metastasis. Molecules that hijack endogenous transport mechanisms on the brain endothelium (brain shuttles) have been shown to increase the transport of large molecules and nanoparticles across the BBB. Among these shuttles, protease-resistant peptides such as MiniAp-4 are particularly efficient. Here, we report the synthesis, characterization, and evaluation of site-specific mAb-brainshuttle antibody conjugates (ASC) based on the anti-HER2 mAb trastuzumab (Tz) and four molecules of MiniAp-4. The ASCs preserve the binding and cell cycle arrest capacity of Tz. MiniAp-4 ASC displays enhanced transport across an in vitro BBB cellular model with respect to Tz and Tz conjugated to Angiopep-2, the brain shuttle that has advanced the most in clinical trials. More importantly, evaluation of Tz-MiniAp4 in a murine brain metastasis model demonstrated that the protease-resistant peptide showed preferential transport across the BBB/BTB, displaying a marked therapeutic effect and protecting against metastasis development. The technology described herein could be applied to any antibody of interest to treat central nervous system-related diseases. MiniAp-4 enhances the brain transport of the monoclonal antibody trastuzumab, preventing brain metastasis.