EVI1 Promotes the Proliferation and Invasive Properties of Human Head and Neck Squamous Cell Carcinoma Cells.

Head and neck squamous cell carcinoma (HNSCC) is a frequent malignancy with a poor prognosis. So far, the EGFR inhibitor cetuximab is the only approved targeted therapy. A deeper understanding of the molecular and genetic basis of HNSCC is needed to identify additional targets for rationally designed, personalized therapeutics. The transcription factor EVI1, the major product of the MECOM locus, is an oncoprotein with roles in both hematological and solid tumors. In HNSCC, high EVI1 expression was associated with an increased propensity to form lymph node metastases, but its effects in this tumor entity have not yet been determined experimentally. We therefore overexpressed or knocked down EVI1 in several HNSCC cell lines and determined the impact of these manipulations on parameters relevant to tumor growth and invasiveness, and on gene expression patterns. Our results revealed that EVI1 promoted the proliferation and migration of HNSCC cells. Furthermore, it augmented tumor spheroid formation and the ability of tumor spheroids to displace an endothelial cell layer. Finally, EVI1 altered the expression of numerous genes in HNSCC cells, which were enriched for Gene Ontology terms related to its cellular functions. In summary, EVI1 represents a novel oncogene in HNSCC that contributes to cellular proliferation and invasiveness.

Neurological symptom burden impacts survival prognosis in patients with newly diagnosed non-small cell lung cancer brain metastases.

BACKGROUND: Brain metastases (BM) are a frequent complication of advanced cancer and are characterized by a variety of neurological symptoms. Although the presence of neurological symptoms is included in the response assessment in patients with primary brain tumors, to the authors' knowledge little is known regarding the prognostic impact of neurological symptoms in patients with BM. METHODS: Patients with newly diagnosed BM from non-small cell lung cancer were identified from the Vienna Brain Metastasis Registry and were evaluated according to the incidence, distribution, and prognostic impact of neurological symptoms at the time of diagnosis of BM. RESULTS: A total of 1608 patients (57.3% male and 42.7% female; median age, 62 years) were available for further analyses. Neurological symptoms including focal deficits (985 patients; 61.3%), signs of increased intracranial pressure (483 patients; 30.0%), epileptic seizures (224 patients; 13.9%), and neuropsychological symptoms (233 patients; 14.5%) were documented in 1186 of the 1608 patients (73.8%). Patients with asymptomatic BM presented with a longer median overall survival after the diagnosis of BM compared with patients with symptomatic BM (11 months vs 7 months; P < .001). In multivariate analysis with a diagnosis-specific graded prognostic assessment (hazard ratio, 1.41; 95% CI, 1.33-1.50 [P < .001]), the presence of neurological symptoms (hazard ratio, 1.39; 95% CI, 1.23-1.57 [P < .001]) was found to be independently associated with survival prognosis from the time of diagnosis of BM. CONCLUSIONS: Neurological symptoms at the time of BM diagnosis demonstrated a strong and independent association with survival prognosis. The results of the current study have highlighted the need for the integration of the presence of neurological symptoms into the prognostic assessment of patients with BM from non-small cell lung cancer. LAY SUMMARY: Neurological symptom evaluation is included regularly in the assessment of patients with primary brain tumors. However, to the authors' knowledge, little is known regarding the prognostic impact in patients with newly diagnosed brain metastases (BM). The current study has provided a detailed clinical characterization of the incidence, distribution, and prognostic impact of neurological symptoms in a large, real-life cohort of patients with BM from non-small cell lung cancer. In this cohort, neurological symptoms at the time of diagnosis of BM demonstrated a strong, independent prognostic impact on the survival prognosis. The results of the current study have highlighted the need for the integration of neurological symptom burden into the prognostic assessment of patients with BM from non-small cell lung cancer.

Analysis of the inflammatory tumor microenvironment in meningeal neoplasms.

BACKGROUND: Properties of the inflammatory tumor microenvironment are associated with disease subtype, grade, and prognosis in various cancer entities. As immune-modulatory therapies are currently being explored in patients with meningeal neoplasms, we investigated their inflammatory microenvironment (meningiomas and solitary fibrous tumor/hemangiopericytoma (SFT/HPC)). MATERIALS AND METHODS: 74 meningeal tumor specimens: (10/74 (13.5%) atypical meningioma; 8/74 (10.8%) anaplastic meningioma; 8/74 (10.8%) chordoid meningioma; 9/74 (12.2%) fibroblastic meningioma; 10/74 (13.5%) transitional meningioma; 3/74 (4.1%) rhabdoid meningioma; 7/74 (9.5%) meningothelial meningioma; SFT/HPC (19/74 (25.7%) were retrieved from the Neuro-Biobank, Medical University of Vienna, Austria. RESULTS: Tumor-infiltrating lymphocyte (TIL) infiltration could be observed in the majority of the investigated specimens (CD3+: 66/74 (89.2%); CD8+: 47/74 (63.5%); CD45RO+: 29/73 (39.2%); FOXP3+ 19/74 (25.7%); PD1+: 3/74 (4.1%). No difference in TIL infiltration was observed between SFT/HPC and meningioma cases. Higher density of FOXP3+ TILs was observed with increasing WHO grade in meningioma specimens (p = 0.005). Membranous programmed cell death ligand 1 (PD-L1) expression was observed in 4/74 (5.4%) specimens, with 3/74 (4.1%) presenting with 1% and 1/74 (1.4%) with 3% PD-L1 expressing tumor cells. Lymphatic vessels as identified by podoplanin immunohistochemistry were observed in 10/74 (13.5%) specimens and were significantly associated with presence of membranous PD-L1 expression on tumor cells (p = 0.003). CONCLUSION: Infiltration by various TIL subtypes can be observed in the majority of meningeal neoplasms, with enrichment of FOXP3-positive regulatory T-cells in higher-grade meningioma. PD-L1 expression on tumor cells was only infrequently found. A better understanding of the pathobiological role of the immune system in meningeal neoplasms may facilitate development of immunomodulatory treatment approaches in meningeal tumors.

DNA methylation-based classification and grading system for meningioma: a multicentre, retrospective analysis.

BACKGROUND: The WHO classification of brain tumours describes 15 subtypes of meningioma. Nine of these subtypes are allotted to WHO grade I, and three each to grade II and grade III. Grading is based solely on histology, with an absence of molecular markers. Although the existing classification and grading approach is of prognostic value, it harbours shortcomings such as ill-defined parameters for subtypes and grading criteria prone to arbitrary judgment. In this study, we aimed for a comprehensive characterisation of the entire molecular genetic landscape of meningioma to identify biologically and clinically relevant subgroups. METHODS: In this multicentre, retrospective analysis, we investigated genome-wide DNA methylation patterns of meningiomas from ten European academic neuro-oncology centres to identify distinct methylation classes of meningiomas. The methylation classes were further characterised by DNA copy number analysis, mutational profiling, and RNA sequencing. Methylation classes were analysed for progression-free survival outcomes by the Kaplan-Meier method. The DNA methylation-based and WHO classification schema were compared using the Brier prediction score, analysed in an independent cohort with WHO grading, progression-free survival, and disease-specific survival data available, collected at the Medical University Vienna (Vienna, Austria), assessing methylation patterns with an alternative methylation chip. FINDINGS: We retrospectively collected 497 meningiomas along with 309 samples of other extra-axial skull tumours that might histologically mimic meningioma variants. Unsupervised clustering of DNA methylation data clearly segregated all meningiomas from other skull tumours. We generated genome-wide DNA methylation profiles from all 497 meningioma samples. DNA methylation profiling distinguished six distinct clinically relevant methylation classes associated with typical mutational, cytogenetic, and gene expression patterns. Compared with WHO grading, classification by individual and combined methylation classes more accurately identifies patients at high risk of disease progression in tumours with WHO grade I histology, and patients at lower risk of recurrence among WHO grade II tumours (p=0·0096) from the Brier prediction test). We validated this finding in our independent cohort of 140 patients with meningioma. INTERPRETATION: DNA methylation-based meningioma classification captures clinically more homogenous groups and has a higher power for predicting tumour recurrence and prognosis than the WHO classification. The approach presented here is potentially very useful for stratifying meningioma patients to observation-only or adjuvant treatment groups. We consider methylation-based tumour classification highly relevant for the future diagnosis and treatment of meningioma. FUNDING: German Cancer Aid, Else Kröner-Fresenius Foundation, and DKFZ/Heidelberg Institute of Personalized Oncology/Precision Oncology Program.

Expression profiling of angiogenesis-related genes in brain metastases of lung cancer and melanoma.

Brain metastases (BM) are the most common brain tumors of adults and are associated with fatal prognosis. Formation of new blood vessels, named angiogenesis, was proposed to be the main hallmark of the growth of BM. Previous preclinical evidence revealed that angiogenic blockage might be considered for treatment; however, there were varying responses. In this study, we aimed to characterize the expression pattern of angiogenesis-related genes in BM of lung cancer and melanoma, which might be of importance for the different responses against anti-angiogenic treatment. Fifteen snap-frozen tissues obtained from BM of non-small cell lung cancer (NSCLC), small-cell lung cancer (SCLC), and melanoma patients were analyzed for angiogenesis-related genes using a commercially available gene expression kit. Epilepsy tissue was used as control. Expression values were analyzed using hierarchical clustering investigating relative fold changes and mapping to Omicsnet protein interaction network. CXCL10, CEACAM1, PECAM1, KIT, COL4A2, COL1A1, and HSPG2 genes were more than 50-fold up-regulated in all diagnosis groups when compared to control, whereas genes such as ANGPT4, PDGFRB, and SERPINF1 were down-regulated only in SCLC and melanoma groups, respectively. Using hierarchical clustering, 12 out of 15 cases were allocated to the correct histological primary tumor type. We identified genes with consistent up-regulation in BM of lung cancer and melanoma and other genes with differential expression across BM of these tumor types. Our data may be of relevance for targeted therapy or prophylaxis of BM using anti-angiogenic agents.

Tumor infiltrating lymphocytes and PD-L1 expression in brain metastases of small cell lung cancer (SCLC).

Brain metastases (BM) are frequent in small cell lung cancer (SCLC). Novel insights into their pathobiology are needed for development of better therapies. We investigated tumor-infiltrating lymphocyte (TIL) subsets (CD3+, CD8+, CD45RO+, FOXP3+ and PD-1+) and expression of PD-L1 in a series of 32 SCLC BM specimens and four matched primary tumor specimens using immunohistochemistry. 30/32 (93.8 %) BM specimens showed TIL infiltration. CD3+ TILs were observed in 30/32 (93.8 %) BM specimens, CD8+ TILs in 25/32 (78.1 %), CD45RO+ TILs in 15/32 (46.9 %), FOXP3+ TILs in 15/32 (46.9 %) and PD-1+ TILs in 1/32 (3.1 %) BM specimens. Patients with infiltration of CD45RO+ TILS had a significantly longer median survival time (11 months; 95 % CI 0.000-26.148) as compared to patients without the presence of CD45RO+ TILs (5 months; 95 % CI 0.966-9.034; p = 0.007; log rank test). Membranous PD-L1 on tumor cells was observed in 24/32 (75.0 %) BM specimens, with 11/32 (34.4 %) cases showing PD-L1 expression in over 5 % of viable BM tumor cells. PD-L1 expression on TILs was seen in 8/32 (25.0 %) and on tumor infiltrating macrophages in 9/32 (28.1 %) cases. Patients with PD-L1 expression on TILs presented with improved survival prognosis (6 versus 29 months; p = 0.002; log rank test). Among matched primary tumors, all (4/4; 100 %) specimens showed TIL infiltration, while PD-L1 expression found in only 1/4 (25.0 %) specimen. TIL infiltration and PD-L1 expression are commonly found in SCLC BM and presence of CD45RO+ memory T-cells and PD-L1+ TILs in SCLC BM seem to associate with favorable survival times. Our data suggest an active immune microenvironment in SCLC BM that may be targetable by immune-modulating drugs.

Tumour-infiltrating lymphocytes and expression of programmed death ligand 1 (PD-L1) in melanoma brain metastases.

AIMS: In this study we aimed to characterize immune infiltrates and expression of programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) in a series of melanoma BM to provide a basis for experimental therapy using immune checkpoint inhibitors. METHODS AND RESULTS: We investigated expression of PD-1, PD-L1, CD3, CD8, CD45RO, forkhead box protein 3 (FoxP3), CD20 and BRAF V600E by immunohistochemistry in melanoma BM samples. Forty-three specimens [27 of which (62.8%) were BRAF V600E-positive] were available. CD3(+) tumour-infiltrating lymphocytes (TILs) were evident in 33 specimens (76.7%), CD8(+) in 39 (90.7%), CD45RO(+) in 32 (74.4%), PD-1(+) in 27 (62.8%), FoxP3(+) in 21 (48.8%) and CD20(+) TILs in 19 (44.2%). Tumour PD-L1 expression was observed in 22 specimens (51.1%), and in nine of these (40.9%) expression was observed in more than 5% of tumour cells. PD-L1 expression was associated with higher density of PD-1(+) (P < 0.001), CD3(+) (P = 0.014) and FoxP3(+) (P < 0.001) TIL infiltration. Density of CD3(+) TILs was associated with density of CD8(+) (P < 0.001), PD-1(+) (P < 0.001) and CD45RO(+) (P < 0.001) TILs. PD-L1 expression or PD-1(+) , CD3(+) , CD8(+) or CD45RO(+) TILs density did not correlate with BRAF V600E status, previous systemic therapy or survival (P > 0.05). CONCLUSIONS: Melanoma BM showed considerable lymphocytic infiltrates and expression of PD-L1 in the majority of investigated specimens, with high PD-L1 expression found predominantly in regions of abundant inflammation. Our data indicate that clinical studies should investigate the value of checkpoint inhibitors in patients with melanoma BMs.

BRAF alterations in brain tumours: molecular pathology and therapeutic opportunities.

PURPOSE OF REVIEW: To summarize the current knowledge on v-RAF murine sarcoma viral oncogene homologue B1 (BRAF) aberrations in tumours of the central nervous system. RECENT FINDINGS: BRAF alterations are found in variable frequencies across a wide spectrum of diverse central nervous system neoplasms. BRAF V600 point mutations (most commonly of the V600E type) are most common in pleomorphic xanthoastrocytoma (approximately 60% of cases), gangliogliomas (50%), dysembryoplastic neuroepithelial tumours (30%), Langerhans cell histiocytosis (50%), melanoma brain metastases (50%) and papillary craniopharyngiomas (96%) and are also detectable in a fraction of glioblastomas (overall mutation rate of 2-12%, with a higher rate of approximately 50% in epithelioid glioblastomas). BRAF fusions (most commonly KIAA1549: BRAF) are typical for pilocytic astrocytomas and are almost absent from other tumour types. Clinical trials have established tyrosine-kinase inhibitors of BRAF as feasible treatment option in selected patients with mutation-bearing brain metastases of melanoma. Preclinical studies, some case reports and small patient series have documented tumour responses of primary brain tumours with BRAF aberrations to BRAF inhibition. SUMMARY: Molecular testing for BRAF alterations in brain tumours may be of clinical relevance for differential diagnostic considerations in some situations or to guide selection of patients for targeted therapy with specific inhibitors. Prospective clinical trials evaluating the efficacy of BRAF inhibitors in central nervous system tumours are strongly supported by the available evidence.

BRAFV600E mutant protein is expressed in cells of variable maturation in Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a clinically and histologically heterogeneous disorder. Its classification as either reactive inflammatory or neoplastic has been a matter of debate. However, the recent finding of frequent BRAFV600E mutations in LCH argues for the latter. The exact cell type that harbors the mutation and is responsible for proliferation remains to be identified. We here apply a BRAFV600E mutation-specific antibody to detect the BRAF mutant cells in lesions from 89 patients with LCH. We found BRAFV600E mutations in 34 of 89 (38%) lesions. In lesions with the BRAFV600E mutation, the majority of cells coexpressing S-100 and CD1a harbored mutant BRAFV600E protein. These cells also expressed CD14 and CD36, whereas various fractions exhibited CD207. On the other hand, CD80 and CD86 expression was also present on BRAFV600E-positive cells. Thus, cells of variable maturation, exhibiting an immunohistochemical profile compatible either with myeloid cell or with dedifferentiated Langerhans cell antigens, carry the BRAFV600E mutation. In conclusion, we identify and characterize the neoplastic cells in LCH with BRAFV600E mutations by applying a mutation-specific marker and demonstrate feasibility for routine screening.

Predictive molecular markers in metastases to the central nervous system: recent advances and future avenues.

Metastases to the central nervous system (CNS) are common in several cancer types. For most primary tumors that commonly metastasize to the CNS, molecular biomarker analyses are recommended in the clinical setting for selection of appropriate targeted therapies. Therapeutic efficacy of some of these agents has been documented in patients with brain metastases, and molecular testing of CNS metastases should be considered in the clinical setting. Here, we summarize the clinically relevant biomarker tests that should be considered in neurosurgical specimens based on the current recommendations of the European Society of Medical Oncology (ESMO) or the National Comprehensive Cancer Network (NCCN) for the most relevant primary tumor types: lung cancer (EGFR mutations, ALK rearrangement, BRAF mutations), breast cancer (HER2 amplification, steroid receptor overexpression), melanoma (BRAF mutations), and colorectal cancer (RAS mutations). Furthermore, we discuss emerging therapeutic targets including novel oncogenic alterations (ROS1 rearrangements, FGFR1 amplifications, CMET amplifications, and others) and molecular features of the tumor microenvironment (including immune-checkpoint molecules such as CTLA4 and PD-1/PD-L1). We also discuss the potential role of advanced biomarker tests such as next-generation sequencing and "liquid biopsies" for patients with CNS metastases.

microRNA expression pattern modulates temozolomide response in GBM tumors with cancer stem cells.

Temozolomide (TMZ) is widely used to treat glioblastoma multiforme (GBM). Although the MGMT gene methylation status is postulated to correlate with TMZ response, some patients with a methylated MGMT gene still do not benefit from TMZ therapy. Cancer stem cells (CSCs) may be one of the causes of therapeutic resistance, but the molecular mechanism underlying this resistance is unclear. microRNA (miRNA) deregulation has been recognized as another chemoresistance modulating mechanism. Thus, we aimed to evaluate the miRNA expression patterns associated with chemoresistance that is dependent on the CSC status in GBM tumors to identify therapeutic biomarkers. CSCs were identified in 5 of 20 patients' tumor tissues using magnetic separation. CSC (+) tumors displayed a significant induction of CpG island methylation in the MGMT gene promoter (p = 0.009). Using real-time reverse transcription polymerase chain reaction (qRT-PCR), 9 miRNAs related to GBM (mir-181b, miR-153, miR-137, miR-145, miR-10a, miR-10b, let-7d, miR-9, and miR-455-3p), which are associated with cell cycle and invasion was analyzed in tumor samples. Low miR-181b and high miR-455-3p expression levels were detected (p = 0.053, p = 0.004; respectively) in CSC (+) tumors. Analysis revealed a significant correlation between miR-455-3p expression and Smad2 protein levels as analyzed by immunohistochemistry in CSC (+) tumors (p = 0.002). Thus, miR-455-3p may be involved in TMZ resistance in MGMT methylated CSC (+) GBM patients. Further studies and evaluations are required, but this miRNA may provide novel therapeutic molecular targets for GBM treatment and new directions for the development of anticancer drugs.

PD1 (CD279) and PD-L1 (CD274, B7H1) expression in primary central nervous system lymphomas (PCNSL).

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a malignant brain tumor with limited treatment options and shows prominent infiltration by tumor infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs). Programmed death 1 (PD1; CD279) and its ligand PD-L1 (B7H1, CD274) promote escape of tumor cells from immune surveillance in several tumor types, but no data are available on PCNSL. Agents inhibiting PD1 and PD-L1 are showing compelling antitumor activity in current clinical trials in solid and hematological cancers. METHODS: We investigated PD1 (clone NAT ab52587) and PD-L1 (clone 5H1) expression in large neurosurgical resection specimens of 20 immunocompetent historical PCNSL patients using immunohistochemistry. RESULTS: We found expression of PD1 and/or PD-L1 on tumor cells, TILs, or TAMs in a total of 18/20 (90%) of PCNSL cases. In 12/20 (60%) cases, intratumoral PD1-positive TILs were present (low density: 9/20, 45%; moderate density: 2/20, 10%; high density: 1/20, 5%) with additional peritumoral accumulation of PD1-positive lymphocytes in all of 12 cases with evaluable adjacent brain tissue on the tissue section. PD-L1 expressing intratumoral TAMs were found in 4/20 (20%) tumors. In 2/20 (10%) and 4/20 (20%) specimens, we observed striking PD-L1 or PD1 expression on PCNSL tumor cells, respectively. Median number of CD8-positive TILs was 517/mm2 (range 75 - 2,470) and did not correlate with PD1 or PD-L1 expression (p > 0.05, Kruskal- Wallis test). CONCLUSIONS: PD1 and PDL1 are immunohistochemically detectable in PCNSL and may be involved in creating an immunosuppressive microenvironment. Specific immune checkpoint inhibitors may be considered for experimental therapy approaches in this disease.

Immune cell distribution and DNA methylation signatures differ between tumor and stroma enriched compartment in pancreatic ductal adenocarcinoma.

The presence of abundant tumor stroma is a prominent characteristic of pancreatic ductal adenocarcinomas (PDAC) that potentially influences disease progression and therapy response. This study aims to investigate immune cell infiltration and epigenetic profiles in tumor cell enriched ("Tumor") and stroma cell enriched ("Stroma") regions within human PDAC tissue samples. By comparing those regions, we identified 25,410 differentially methylated positions (DMPs) distributed across 6,963 unique genes. Pathway enrichment analysis using the top 2,000 DMPs that were either hyper- or hypomethylated indicated that immune response pathways and the estrogen receptor pathway are epigenetically dysregulated in Tumor and Stroma regions, respectively. In terms of immune cell infiltration, we observed overall low levels of T cells in both regions. In Tumor regions however, occurrence of tumor-associated macrophages (TAMs) was higher than in Stroma regions (p = 0.02) concomitant with a dualistic distribution that stratifies PDAC patients into those with high and low TAM infiltration. By categorizing TAM levels into quartiles, our analysis revealed that PDAC patients with more than 1,515 TAMs per mm² exhibited significantly shorter overall survival (p = 0.036). Our data suggest that variations in inflammatory characteristics between the Tumor and Stroma defined compartments of PDAC may primarily stem from the presence of macrophages rather than lymphocytes. The abundance of TAMs within regions enriched with tumor cells correlates with patient survival, underscoring the potential significance of exploring therapeutic interventions targeting TAMs. Furthermore, directing attention towards the estrogen receptor pathway may represent a promising strategy to address the stroma cell component within the PDAC tumor microenvironment.

DNA Methylation Signatures Correlate with Response to Immune Checkpoint Inhibitors in Metastatic Melanoma.

BACKGROUND: DNA methylation profiles have emerged as potential predictors of therapeutic response in various solid tumors. OBJECTIVE: This study aimed to analyze the DNA methylation profiles of patients with stage IV metastatic melanoma undergoing first-line immune checkpoint inhibitor treatment and evaluate their correlation with a radiological response according to immune-related Response Evaluation Criteria in Solid Tumors (iRECIST). METHODS: A total of 81 tissue samples from 71 patients with metastatic melanoma (27 female, 44 male) were included in this study. We utilized Illumina Methylation EPIC Beadchips to retrieve their genome-wide methylation profile by interrogating >850,000 CpG sites. Clustering based on the 500 most differentially methylated genes was conducted to identify distinct methylation patterns associated with immune checkpoint inhibitor response. Results were further aligned with an independent, previously published data set. RESULTS: The median progression-free survival was 8.5 months (range: 0-104.1 months), and the median overall survival was 30.6 months (range: 0-104.1 months). Objective responses were observed in 29 patients (40.8%). DNA methylation profiling revealed specific signatures that correlated with radiological response to immune checkpoint inhibitors. Three distinct clusters were identified based on the methylation patterns of the 500 most differentially methylated genes. Cluster 1 (12/12) and cluster 2 (12/24) exhibited a higher proportion of responders, while cluster 3 (39/45) predominantly consisted of non-responders. In the validation data set, responders also showed more frequent hypomethylation although differences in the data sets limit the interpretation. CONCLUSIONS: These findings suggest that DNA methylation profiling of tumor tissues might serve as a predictive biomarker for immune checkpoint inhibitor response in patients with metastatic melanoma. Further validation studies are warranted to confirm the efficiency of DNA methylation profiling as a predictive tool in the context of immunotherapy for metastatic melanoma.

AKT1E17K mutations cluster with meningothelial and transitional meningiomas and can be detected by SFRP1 immunohistochemistry.

The activating E17K mutation in the AKT1 gene has been detected in several tumor entities. Currently several clinical studies with specific AKT1 inhibitors are under way. To determine whether AKT1 mutations are involved in human tumors of the nervous system, we examined a series of 1,437 tumors including 391 primary intracranial brain tumors and 1,046 tumors of the coverings of the central and peripheral nervous system. AKT1E17K mutations were exclusively seen in meningiomas and occurred in 65 of 958 of these tumors. A strong preponderance was seen in the variant of meningothelial meningioma WHO grade I of basal and spinal localization. In contrast, AKT1E17K mutations were rare in WHO grade II and absent in WHO grade III meningiomas. In order to more effectively detect this mutation, we tested for immunohistochemical markers associated with this alteration. We observed strong up-regulation of SFRP1 expression in all meningiomas with AKT1E17K mutation and in HEK293 cells after transfection with mutant AKT1E17K, but not in meningiomas and HEK293 cells lacking this mutation.

Comparison of microRNA expression levels between initial and recurrent glioblastoma specimens.

Glioblastoma is the most frequent primary brain tumour in adults. Recent therapeutic advances increased patient's survival, but tumour recurrence inevitably occurs. The pathobiological mechanisms involved in glioblastoma recurrence are still unclear. MicroRNAs are small RNAs proposed o have important roles for cancer including proliferation, aggressiveness and metastases development. There exist only few data on the involvement of microRNAs in glioblastoma recurrence. We selected the following 7 microRNAs with potential relevance for glioblastoma pathobiology by means of a comprehensive literature search: microRNA-10b, microRNA-21, microRNA-181b, microRNA-181c, microRNA-195, microRNA-221 and microRNA-222. We further selected 15 primary glioblastoma patients, of whom formalin fixed and paraffin embedded tissue (FFPE) of the initial and recurrence surgery were available. All patients had received first line treatment consisting of postoperative combined radiochemotherapy with temozolomide (n = 15). Non-neoplastic brain tissue samples from 3 patients with temporal lobe epilepsy served as control. The expression of the microRNAs were analysed by RT-qPCR. These were correlated with each other and with clinical parameters. All microRNAs showed detectable levels of expressions in glioblastoma group, whereas microRNA-10b was not detectable in epilepsy patients. MicroRNAs except microRNA-21 showed significantly higher levels in epilepsy patients when compared to the levels of first resection of glioblastoma. Comparison of microRNA levels between first and second resections revealed no significant change. Cox regression analyses showed no significant association of microRNA expression levels in the tumor tissue with progression free survival times. Expression levels of microRNA-10b, microRNA-21, microRNA-181b, microRNA-181c, microRNA-195, microRNA-221 and microRNA-222 do not differ significantly between initial and recurrent glioblastoma.

Clinical characteristics, treatment, and long-term outcome of patients with brain metastases from thyroid cancer.

Brain metastases (BM) in patients with thyroid cancer (TC) are rare with an incidence of 1% for papillary and follicular, 3% for medullary and up to 10% for anaplastic TC (PTC, FTC, MTC and ATC). Little is known about the characteristics and management of BM from TC. Thus, we retrospectively analyzed patients with histologically verified TC and radiologically verified BM identified from the Vienna Brain Metastasis Registry. A total of 20/6074 patients included in the database since 1986 had BM from TC and 13/20 were female. Ten patients had FTC, 8 PTC, one MTC and one ATC. The median age at diagnosis of BM was 68 years. All but one had symptomatic BM and 13/20 patients had a singular BM. Synchronous BM at primary diagnosis were found in 6 patients, while the median time to BM diagnosis was 13 years for PTC (range 1.9-24), 4 years for FTC (range 2.1-41) and 22 years for the MTC patient. The overall survival from diagnosis of BM was 13 months for PTC (range 1.8-57), 26 months for FTC (range 3.9-188), 12 years for the MTC and 3 months for the ATC patient. In conclusion, development of BM from TC is exceedingly rare and the most common presentation is a symptomatic single lesion. While BM generally constitute a poor prognostic factor, individual patients experience long-term survival following local therapy.

Frequent Overexpression of HER3 in Brain Metastases from Breast and Lung Cancer.

PURPOSE: HER3 belongs to a family of receptor tyrosine kinases with oncogenic properties and is targeted by a variety of novel anticancer agents. There is a huge unmet medical need for systemic treatment options in patients with brain metastases (BM). Therefore, we aimed to investigate HER3 expression in BM of breast (BCa) and non-small cell lung cancer (NSCLC) as the basis for future clinical trial design. EXPERIMENTAL DESIGN: We analyzed 180 BM samples of breast cancer or NSCLC and 47 corresponding NSCLC extracranial tissue. IHC was performed to evaluate protein expression of HER3, and immune cells based on CD3, CD8, and CD68. To identify dysregulated pathways based on differential DNA methylation patterns, we used Infinium MethylationEPIC microarrays. RESULTS: A total of 99/132 (75.0%) of BCa-BM and 35/48 (72.9%) of NSCLC-BM presented with HER3 expression. Among breast cancer, HER2-positive and HER2-low BM showed significantly higher rates of HER3 coexpression than HER2-negative BM (87.1%/85.7% vs. 61.0%, P = 0.004). Among NSCLC, HER3 was more abundantly expressed in BM than in matched extracranial samples (72.9% vs. 41.3%, P = 0.003). No correlation of HER3 expression and intratumoral immune cell density was observed. HER3 expression did not correlate with overall survival from BM diagnosis. Methylation signatures differed according to HER3 status in BCa-BM samples. Pathway analysis revealed subtype-specific differences, such as TrkB and Wnt signaling pathways dysregulated in HER2-positive and triple-negative breast cancer BM, respectively. CONCLUSIONS: HER3 is highly abundant in BM of breast cancer and NSCLC. Given the promising results of antibody-drug conjugates in extracranial disease, BM-specific trials that target HER3 are warranted. See related commentary by Kabraji and Lin, p. 2961.

Direct image to subtype prediction for brain tumors using deep learning.

Background: Deep Learning (DL) can predict molecular alterations of solid tumors directly from routine histopathology slides. Since the 2021 update of the World Health Organization (WHO) diagnostic criteria, the classification of brain tumors integrates both histopathological and molecular information. We hypothesize that DL can predict molecular alterations as well as WHO subtyping of brain tumors from hematoxylin and eosin-stained histopathology slides. Methods: We used weakly supervised DL and applied it to three large cohorts of brain tumor samples, comprising N = 2845 patients. Results: We found that the key molecular alterations for subtyping, IDH and ATRX, as well as 1p19q codeletion, were predictable from histology with an area under the receiver operating characteristic curve (AUROC) of 0.95, 0.90, and 0.80 in the training cohort, respectively. These findings were upheld in external validation cohorts with AUROCs of 0.90, 0.79, and 0.87 for prediction of IDH, ATRX, and 1p19q codeletion, respectively. Conclusions: In the future, such DL-based implementations could ease diagnostic workflows, particularly for situations in which advanced molecular testing is not readily available.