Pentoxifylline and Vitamin E Can Restrict Radiation Necrosis via Vascular Pathways, Experimental Study in an Animal Model.

OBJECTIVE: Radiation necrosis (RN) is a long-term side effect of Gamma Knife stereotactic radiosurgery that may require surgical intervention. Pentoxifylline and vitamin E have previously been shown to be effective in the treatment of RN in the published literature, but there are no data on the prophylactic use of these molecules or, more importantly, whether prophylaxis is required. METHODS: The iatrogenic RN model included 50 Sprague-Dawley rats of both sexes. There were 7 treatment subgroups established. Gamma-Plan 8.32 was used to plan after magnetic resonance scans were performed in a specially designed frame. The injection doses used in the treatment groups were vitamin E (30 mg/kg/day in a single dose) and pentoxifylline (50 mg/kg/day in 2 doses). Control magnetic resonance scans were performed at the end of a 16-week treatment, and the subjects were decapitated for pathological evaluations. RESULTS: The intensity of hypoxia - inducible factor 1α immunoreactivity is statistically significantly lower in the therapeutic vitamin E, prophylactic pentoxifylline and vitamin E, and therapeutic pentoxifylline and vitamin E groups than in the other groups. Similarly, the intensity of vascular endothelial growth factor immunoreactivity was reduced in the therapeutic vitamin E and prophylactic pentoxifylline and vitamin E treatment modality groups. When compared with other groups, the therapeutic pentoxifylline group had significantly fewer vascular endothelial growth factor-immunoreactive cells in the perinecrotic area, with an accompanying decreased contrast enhancement pattern. CONCLUSIONS: Both vitamin E and pentoxifylline are effective for the treatment and/or restriction of RN, either alone or in combination. The use of these molecules as a preventive measure did not outperform the therapeutic treatment.

Langerhans cell histiocytosis located in the spheno-orbital bone and the pons: illustrative case.

BACKGROUND: This is a case of aggressive Langerhans cell histiocytosis (LCH) with an atypical intracranial location. OBSERVATIONS: In this report, the authors present the diagnosis and treatment of a 12-year-old male patient diagnosed with LCH. The patient was admitted to the emergency department with left-sided facial palsy, and a solid lesion with mass effect in the pons was found. A biopsy was performed via suboccipital craniotomy, and the diagnosis was LCH. A chemotherapy regimen was started since the LCH sample was the resistant type. The patient showed improvement in his neurological deficit following treatment. LESSONS: This rare localized and aggressive case's diagnosis process and treatment choices may apply to future cases.

Mesenchymal stem cells differentiate to retinal ganglion-like cells in rat glaucoma model induced by polystyrene microspheres.

AIM: The study aimed to evaluate the differentiation ability of intravitreally injected rat bone marrow-derived mesenchymal stem cells (rBM-MSCs) to retinal ganglion-like cells in a polystyrene microsphere induced rat glaucoma model. MATERIALS AND METHODS: The glaucoma rat model was generated via intracameral injection of 7 microliter polystyrene microspheres. Green fluorescence protein-labeled (GFP) rBM-MSCs were transplanted intravitreally at or after induction of ocular hypertension (OHT), depending on the groups. By the end of the fourth week, flat-mount retinal dissection was performed, and labeled against Brn3a, CD90, GFAP, CD11b, Vimentin, and localization of GFP positive rBM-MSCs was used for evaluation through immunofluorescence staining and to count differentiated retinal cells by flow cytometry. From 34 male Wistar albino rats, 56 eyes were investigated. RESULTS: Flow cytometry revealed significantly increased CD90 and Brn3a positive cells in glaucoma induced and with rBM-MSC injected groups compared to control(P = 0.006 and P = 0.003 respectively), sham-operated (P = 0.007 and P < 0.001 respectively), and only rBM-MSCs injected groups (P = 0.002 and P = 0.009 respectively). Immunofluorescence microscopy revealed differentiation of GFP labeled stem cells to various retinal cells, including ganglion-like cells. rBM-MSCs were observable in ganglion cells, inner and outer nuclear retinal layers in rBM-MSCs injected eyes. CONCLUSION: Intravitreally transplanted rBM-MSCs differentiated into retinal cells, including ganglion-like cells, which successfully created a glaucoma model damaged with polystyrene microspheres. Promisingly, MSCs may have a role in neuro-protection and neuro-regeneration treatment of glaucoma in the future.

Limbic Encephalitis With Dual Positivity.

Limbic encephalitis is a well-defined clinical disorder among paraneoplastic neurological syndromes. Although it is not always possible to identify specific autoantibodies in limbic encephalitis, the presence of anti-neuronal nuclear antibody type 1 (ANNA1 or anti-Hu), anti-Ma2, collapsin response mediator protein 5 (CRMP-5-IgG or anti-CV2), anti-GABAB receptors and anti-amphiphysin antibodies are often detected. A 66-year-old male patient with complaints of forgetfulness was evaluated in our clinic after having seizures. In the neurological examination, the patient was found to be confused. In cranial MR fluid-attenuated inversion recovery (FLAIR) and T2-weighted images, the right hippocampal and parahippocampal structures showed hyperintense areas complying with limbic encephalitis. He had improvement with a course of 2 g/kg intravenous immunoglobulin (IVIG) followed by high-dose methylprednisolone therapy. Following the high-dose methylprednisolone therapy, anti-PCA1 (Yo) and anti-amphiphysin antibodies were positive and the tissue pathology report confirmed combined small-cell carcinoma and large-cell neuroendocrine carcinoma of the lung. In recent years, paraneoplastic neurological syndromes are better recognized with the identification of specific antibodies and the ubiquitous information on pathogenesis. This is the first known report in the literature that a case with both positive anti-PCA1 (Yo) and anti-amphiphysin antibodies together and underlying small-cell and large-cell neuroendocrine carcinomas.

Challenges in the Management of a 7-Year-Old Child with Thyrotropin-Secreting Pituitary Adenoma and the Review of the Literature.

INTRODUCTION: Thyrotropin-producing pituitary adenoma (TSHoma) is a very rare disease, representing less than 1% of the pituitary tumours and presenting with elevated thyroid hormones and normal/high TSH concentrations. CASE PRESENTATION: A 7-year-old boy with nervousness was referred by his psychiatrist for elevated free T4, T3, and TSH levels. Initial evaluation revealed an elevated α-subunit. Pituitary magnetic resonance imaging (MRI) demonstrated a macroadenoma. The patient underwent a trans-sphenoidal tumour resection (TSS) which showed positive immunohistochemical staining for TSH, growth hormone, and prolactin in tumoral tissue. Euthyroidism was achieved for 1 year after TSS, then recurrence of tumour with elevated TSH and thyroid hormone levels necessitated a re-operation with TSS followed by gamma-knife radiosurgery. The euthyroid state was achieved and lasted for 2.5 years this time, but due to the recurrence, medical treatment had been commenced with cabergoline and octreotide. Euthyroidism was maintained for the last 4 years on monthly octreotide treatment. A repeat MRI demonstrated no pituitary mass, but a mass in the sphenoidal sinus had been detected. Removal of this mass by surgery did not achieve euthyroidism. 68Ga-DOTA-TATE positron emission tomography/computed tomography showed residual tissue extending from the pituitary region to the sphenoid sinus. The patient's bone age was advanced by 2 years at diagnosis which became 4 years in 1 year after the diagnosis and remained so throughout follow-up, leading to a final height of -3.3 SDS below his target height at the age of 16 years. CONCLUSION: The diagnosis, treatment, and follow-up of TSHomas are challenging, and short stature due to accelerated bone maturation is a complication of paediatric TSHomas.

Low grade oligodendroglioma seeding around the 4th ventricle.

We report a 45 years old female patient with a left temporal grade II oligodendroglioma that recurred on the wall of the fourth ventricle at grade II oligodendroglioma.

Towards Development of a Standard Terminology of the World Health Organization Classification of Tumors of the Central Nervous System in the Turkish Language, and a Perspective on the Practical Implications of the WHO Classification for Low and Middle Income Countries.

In our manuscript, we propose a common terminology in the Turkish language for the newly adopted WHO classification of the CNS tumors, also known as the WHO CNS 5th edition. We also comment on the applicability of this new scheme in low and middle income countries, and warn about further deepening disparities between the global north and the global south. This division, augmented by the recent COVID-19 pandemic, threatens our ability to coordinate efforts worldwide and may create significant disparities in the diagnosis and treatment of cancers between the "haves" and the "have nots".

Past, Present, and Future of Therapies for Pituitary Neuroendocrine Tumors: Need for Omics and Drug Repositioning Guidance.

Innovation roadmaps are important, because they encourage the actors in an innovation ecosystem to creatively imagine multiple possible science future(s), while anticipating the prospects and challenges on the innovation trajectory. In this overarching context, this expert review highlights the present unmet need for therapeutic innovations for pituitary neuroendocrine tumors (PitNETs), also known as pituitary adenomas. Although there are many drugs used in practice to treat PitNETs, many of these drugs can have negative side effects and show highly variable outcomes in terms of overall recovery. Building innovation roadmaps for PitNETs' treatments can allow incorporation of systems biology approaches to bring about insights at multiple levels of cell biology, from genes to proteins to metabolites. Using the systems biology techniques, it will then be possible to offer potential therapeutic strategies for the convergence of preventive approaches and patient-centered disease treatment. Here, we first provide a comprehensive overview of the molecular subtypes of PitNETs and therapeutics for these tumors from the past to the present. We then discuss examples of clinical trials and drug repositioning studies and how multi-omics studies can help in discovery and rational development of new therapeutics for PitNETs. Finally, this expert review offers new public health and personalized medicine approaches on cases that are refractory to conventional treatment or recur despite currently used surgical and/or drug therapy.

Impact of prognostic nutritional index on survival in recurrent glioblastoma.

BACKGROUND: Primary brain tumors are relatively rare malignancy, with high-grade gliomas (glioblastoma multiforme and anaplastic gliomas) are the most common types. We aimed to evaluate the prognostic value of Prognostic Nutritional Index (PNI), which is calculated by lymphocyte count and albumin, in recurrent glioblastoma patients treated with systemic treatment. METHODS: Data of 64 patients with recurrent glioblastoma who received systemic treatment and followed in our clinic between 2012 and 2018 was retrospectively collected and analyzed. PNI was calculated as: [(10×serum albumin (g/dL))+(0.005×total lymphocyte count)]. Patients were categorized according to the median PNI value. We investigated the prognostic role of PNI groups, and survival outcomes. RESULTS: Median value of PNI was 45.7, and median follow-up duration was 9 months (1-68 months). Median overall survival (OS) was 7.9 months (95%CI: 5.5-10.4). Median OS was significantly longer in patients with PNI>45.7 compared to patients with PNI≤45.7 (13.9 months (95%CI: 10.5-17.4), and 4.6 months (95%CI: 2.5-6.8), p<0.001, respectively). In multivariate analysis, PNI was found to be an independent prognostic factor for OS [HR:0.41 (95%CI:0.22-0.74), p=0.03)]. CONCLUSION: In our study, the PNI was found to be an independent prognostic biomarker in patients with recurrent glioblastoma, but further prospective trials are necessary to validate its prognostic role.

Atypical Teratoid Rhabdoid Tumor in a Newborn: Can IVF Be a Risk Factor?

BackgroundIn recent years, with the widespread use of assisted reproductive technologies, questions have arisen regarding the possible relationship between these infertile parents with assisted conception procedures and childhood cancers. Case report: We present a 23-day-old newborn conceived by in vitro fertilization (IVF) with a 53 × 46 × 38 mm intracranial mass detected by magnetic resonance imaging on the 15th postnatal day. The mass, removed on 23rd postnatal day, was an Atypical Teratoid Rhabdoid Tumor (ATRT), WHO grade 4. Conclusions: As far as we know, this is the only neonatally detected ATRT. Further studies are needed to investigate whether there is a causal relationship between IVF and childhood cancers.

Intermediate-Grade Meningeal Melanocytoma in a 19-Month- Old Child with Difficulties in Differential Diagnosis and Management.

Intermediate-grade meningeal melanocytoma (IGM) is a rare tumor that has not been reported in children so far. It is speculated to have more aggressive clinical behavior with undefined best management options. In this study, we present a 19-month-old girl as the first case with IGM in English literature. Preoperative diagnosis was ambiguous, given the unclear patient history and radiological features resembling a growing skull fracture or a congenital parietal bone agenesis subtype. During surgery, a dark gray-black dural area (5 × 7 cm in size) was found and then excised. However, the surgery was complicated due to brain edema and swelling, warranting a second surgery for reconstruction and dural repair. Of the 16 reported adult patients, 14 showed a high recurrence rate without adjuvant radiotherapy; 2 showed no recurrence with adjuvant radiotherapy. No adjuvant radiotherapy was given to our patient since she was 19 months old at the time of diagnosis and showed no recurrence at 48-month follow-up until now. Close monitoring with radiological imaging is of paramount importance for such cases.

Pilocytic Astrocytoma of the Cerebellopontine Angle with cerebrospinal fluid Spread in an Adult: A Case Report / Astrocitoma pilocítico no ângulo pontocerebelar com disseminação liquórica em paciente adulto: Relato de caso

Introduction Pilocytic astrocytoma of the cerebellopontine angle (CPA) is uncommon, and its spread to the cerebrospinal fluid (CSF) at the time of diagnosis has not been reported in the literature. Case Presentation We report the case of a 33-year-old man with multifocal pilocytic astrocytoma diagnosed by magnetic resonance imaging (MRI) and confirmed by histopathological examination, and present the radiological and histopathological findings. Conclusion In the case herein reported, we observed spread of the pilocytic astrocytoma of the CPA to the CSF at the initial diagnosis, and early detection by MRI is very important regarding the treatment modality and prognosis.

Introdução O astrocitoma pilocítico no ângulo pontocerebelar (APC) é incomum, e sua disseminação liquórica no momento do diagnóstico não foi relatada na literatura. Apresentação do Caso Relatamos o caso de um homem de 33 anos com astrocitoma pilocítico multifocal diagnosticado por ressonância magnética (RM) e confirmado por exame histopatológico, e apresentamos os achados radiológicos e histopatológicos. Conclusão No caso relatado, observou-se disseminação liquórica de astrocitoma pilocítico no APC no diagnóstico inicial, e a detecção precoce por RM é muito importante para a modalidade de tratamento e o prognóstico.

Greater presence of receptors for relaxin in the ligamentum teres of female infants who undergo open reduction for developmental dysplasia of the hip.

BACKGROUND: While many factors involved in the etiology of developmental dysplasia of the hip (DDH), one of which is the hormone relaxin. Relaxin concentrations in patients with DDH may lead to pathodynamic changes during hip development by altering the physiological nature of the ligament, as well as by long-term exposure to relaxin during pregnancy. Our objective in this study was to determine the number of relaxin receptors in the ligamentum teres and their role in causing DDH. METHODS: We identified 26 infants between birth and 3 years of age who had undergone open reduction for DDH between 2010 and 2012. 12 hips of 12 miss abortus fetus between 20 to 35 weeks of gestation were used as control group. Specimens obtained from two groups were stained with Relaxin-2 antibody, and the amount of staining for relaxin receptors was determined using an ordinal H score. RESULTS: The mean (SD) H scores of infants with DDH were significantly higher than those of controls: 215 (59) versus 52 (48); P = 0.00; 95% CI. Statistically significant difference between the two groups in terms of gender was not found. CONCLUSION: As a result, increased number of relaxin receptors in the ligamentum teres could be a risk factor for DDH. LEVEL OF EVIDENCE: Level 2, Prospective comparative study.

Impact of prognostic nutritional index on survival in recurrent glioblastoma.

BACKGROUND: Primary brain tumors are relatively rare malignancy, with high-grade gliomas (glioblastoma multiforme and anaplastic gliomas) are the most common types. We aimed to evaluate the prognostic value of Prognostic Nutritional Index (PNI), which is calculated by lymphocyte count and albumin, in recurrent glioblastoma patients treated with systemic treatment. METHODS: Data of 64 patients with recurrent glioblastoma who received systemic treatment and followed in our clinic between 2012 and 2018 was retrospectively collected and analyzed. PNI was calculated as: [(10×serum albumin (g/dL))+(0.005×total lymphocyte count)]. Patients were categorized according to the median PNI value. We investigated the prognostic role of PNI groups, and survival outcomes. RESULTS: Median value of PNI was 45.7, and median follow-up duration was 9 months (1-68 months). Median overall survival (OS) was 7.9 months (95%CI: 5.5-10.4). Median OS was significantly longer in patients with PNI>45.7 compared to patients with PNI≤45.7 (13.9 months (95%CI: 10.5-17.4), and 4.6 months (95%CI: 2.5-6.8), p<0.001, respectively). In multivariate analysis, PNI was found to be an independent prognostic factor for OS [HR:0.41 (95%CI:0.22-0.74), p=0.03)]. CONCLUSION: In our study, the PNI was found to be an independent prognostic biomarker in patients with recurrent glioblastoma, but further prospective trials are necessary to validate its prognostic role.

Effects of Ozone on Injury after Gamma Knife Radiosurgery.

BACKGROUND: At present, gamma knife radiosurgery plays an important role in neurosurgical procedures. Gamma knife radiosurgery has been used to treat many types of brain tumors and as a functional intervention. However, gamma knife treatment has a devastating effect on the normal brain parenchyma surrounding the target point. It causes increased vascular permeability, vasodilation, and swelling in endothelial cells. Ozone has antioxidant, antiapoptotic, and anti-inflammatory effects in the body. Thus, we evaluated the radioprotective effects of ozone in rats undergoing gamma knife radiation. METHODS: In the present study, 24 Sprague-Dawley male rats weighing 250-300 g in 3 groups of 8 rats each were used. The rats were selected randomly. The control group did not receive any gamma knife radiation. The other 2 groups received 50 Gy of radiation, with 1 group given ozone treatment and the other group not given ozone treatment after gamma knife radiosurgery. At 12 weeks after gamma knife radiation, the rats were sacrificed with high-dose anesthetic agents and the tissues prepared for evaluation. The slides were evaluated for necrosis, vacuolization, glial proliferation, and vascular proliferation using hematoxylin-eosin staining. Vascular endothelial growth factor (VEGF) and extracellular matrix metalloproteinase inducer (also known as CD147) were evaluated using immunohistochemical staining. RESULTS: VEGF expression in glial tissue was significantly less in the group receiving ozone (χ2 = 15.00; df = 4; P = 0.005) compared with the group that had not received ozone and was similar to the expression in the control group. CONCLUSIONS: The lower expression of VEGF in the group receiving ozone might cause less edema in the surrounding tissue owing to less degradation of vascular permeability in the rat brain tissue.

Prognostic factors in progressive high-grade glial tumors treated with systemic approach: A single center experience.

PURPOSE: Malignant high-grade gliomas are the most common and aggressive type of primary brain tumor, and the prognosis is generally extremely poor. In this retrospective study, we analyzed the outcome of systemic treatment in recurrent high-grade glioma patients and the impact of prognostic factors on survivals. METHODS: Data from 114 patients with recurrent high-grade glioma who received systemic treatment and followed in our clinic between 2012 and 2018 were retrospectively analyzed. Eastern Cooperative Oncology Group (ECOG) performance status, age, gender, histology, type of surgical resection, side effects after systemic treatment (deep vein thrombosis, hypertension, proteinuria), IDH1 and alpha thalassemia/mental retardation syndrome X-linked (ATRX) mutation status were investigated as prognostic factors for progression-free survival and overall survival. RESULTS: At the time of diagnosis, the median age was 48 (17-77) and 68% of the patients were male. Most common pathologic subtype was glioblastoma multiforme (68%). Median follow-up duration was 9.1 months (1-68 months). Median progression-free survival and overall survival were 6.2 months and 8 months, respectively. In multivariate analysis, ECOG PS, deep venous thrombosis and the presence of ATRX and IDH1 mutation were found to be independent prognostic factors for progression-free survival (p < 0.05) and, ECOG PS, the presence of ATRX and IDH1 mutation for overall survival (p < 0.05). CONCLUSION: Our study is real life data and the median progression-free survival and overall survival rates are similar to the literature. We have found ECOG PS, presence of ATRX and IDH1 mutation to be independent prognostic factors for both progression-free survival and overall survival.

FDG PET/CT Findings of Extrarenal Wilms Tumor Originating From the Spinal Cord.

Extrarenal Wilms tumor (ERWT) is an extremely rare neoplasm of childhood. It occurs predominantly in retroperitoneum and pelvic or inguinal region without involvement of the kidneys. Although the importance of FDG PET/CT in Wilms tumor is well known, its use in ERWT is limited. Herein, we present FDG PET/CT findings of a 3-year-old girl with a lumbar mass, which was later diagnosed with ERWT.

Prognostic value of modified Glasgow prognostic score in recurrent high-grade glial tumors treated with systemic treatment.

OBJECTIVES: Malignant high-grade gliomas are the most common and aggressive type of primary brain tumor. We aimed to evaluate the prognostic value of modified Glasgow Prognostic Score (mGPS), which is combination of C-reactive protein (CRP) and albumin, in recurrent high-grade glioma patients treated with systemic treatment. PATIENTS AND METHODS: Data of 85 patients with recurrent high-grade glioma who received systemic treatment and followed in our clinic between 2012 and 2018 was retrospectively collected and analyzed. Patients were grouped according to mGPS criteria: mGPS-0: CRP < 10 mg/L and albumin >3.5 g/dL; mGPS-1: CRP < 10 mg/L and albumin <3.5 g/dL or CRP > 10 mg/L and albumin >3.5 g/dL; and mGPS-2: CRP > 10 mg/L and albumin <3.5 mg/L. We investigated the prognostic role of mGPS groups, mutations and survival outcomes. RESULTS: There were 42 (49.4 %), 25 (29.6 %), and 18 (21 %) patients in mGPS-0, mGPS-1, and mGPS-2 groups, respectively. Median follow-up duration was 10 months (1-70 months). Median OS was 8.1 months. According to mGPS-0, -1 and -2; median OS was 13.8 months, 7.3 months and 3.6 months respectively (p = 0.003). mGPS, ATRX and IDH-1 mutation status, and ECOG PS were found to be independent prognostic factors for OS. CONCLUSION: In our study, mGPS was found to be an independent prognostic factor in patients with recurrent high-grade gliomas. If validated, mGPS can be used as an objective, easily calculated, cheap, and readily available prognostic model in routine practice.

Analyses of Copy Number Variations in Myxopapillary Ependymomas of Cauda Equina.

AIM: To identify the copy number variations that are specific to myxopapillary ependymomas (MPEs) of the cauda equina. MATERIAL AND METHODS: The patient cohort included five patients who underwent resection of histologically confirmed MPEs. Tumor samples collected during surgery and stored in liquid nitrogen as well as corresponding blood samples collected were analyzed. Genomic DNA from the venous blood and tumor samples was obtained using standard techniques and hybridized to a Cytoscan 750K Array in accordance with the manufacturer’s introductions. RESULTS: As a novel finding, amplification on chromosome 14q32.33 was detected in all tumor and blood samples, except one tumor sample. All tumor tissues also showed amplification on chromosomes 5, 7, 9, and 16. CONCLUSION: Although further studies with larger cohorts are required to identify genes involved in MPE tumorigenesis and to validate our results, these findings provide a basis for advanced molecular biological and genetic studies of MPEs.

Concordance of PD-L1 expression and CD8+ TIL intensity between NSCLC and synchronous brain metastases.

Programmed death-ligand 1 (PD-L1) is suggested to be a predictive biomarker in non-small-cell lung carcinoma (NSCLC). However, the differential expression of PD-L1 in primary lung tumor vs. synchronous metastases, especially brain metastasis (BM), remains unclear. This study assessed the concordance of PD-L1 expression on tumor cells and tumor-infiltrating lymphocytes (TILs) and CD8+ TIL intensity between primary lung tumors and synchronous BMs from 24 NSCLC patients. PD-L1, CD3, and CD8 positivity was determined by immunohistochemistry (IHC). PD-L1 scoring was based on the proportion of tumor cells with membranous expression of PD-L1 and the cutoff values <1%, 1-49%, and ≥50%. CD3 and CD8 positivity in TILs was evaluated semi-quantitatively and the proportion of CD3+/CD8+ TILs was determined. PD-L1 expression on tumor cells and TILs was evaluated in relation to CD3+/CD8+ TIL proportions and the intensity of CD8+ TILs between the paired primary lung and BM tissues. In the primary lung tumors, PD-L1 positivity was observed in 25%, 37.5%, and 37.5% cases for the cutoff values <1%, 1-49%, and ≥50%, respectively. PD-L1 expression on tumor cells was strongly correlated between the paired primary lung and BM tissues, in all cutoff groups. However, PD-L1 expression on TILs and the proportion of CD3+/CD8+ TILs were not strongly correlated in all three groups between the paired primary lung tumors and BMs. The intensity of CD8+ TILs was concordant in only 54.16% of the paired primary lung tumors and BMs. This study showed a high concordance of PD-L1 expression in neoplastic cells between primary NSCLC and synchronous BMs.