BAP1 Mutations Research Articles

Genomic alterations in metastatic renal cell carcinoma (mRCC): Impact on survival and clinical outcomes.

700 Background: Genomic alterations in RCC can serve as biomarkers for response to therapy. Wild type VHL has shown inferior response to VEGF inhibitors, while patients (pts) with mutated VHL have improved outcomes with immunotherapy (IO)/tyrosine kinase inhibitor (TKI) therapy. We describe the impact of genomic alterations on outcomes and response to front-line therapy. Methods: Pts with mRCC who underwent genomic sequencing between 2015-2022 at Indiana University and were treated with front-line therapy were included. Kaplan-Meier method was used to analyze progression free survival (mPFS) and overall survival (OS) using the log rank test to compare groups. Results: 141 pts were included. Median age was 58yrs (range, 24-81). Tumor histology was 68% clear cell, 10% papillary, 9% unclassified, 1% chromophobe, 1% poorly differentiated, and 9% other. 18% of pts had sarcomatoid features; 13% had rhabdoid. 47% pts had metastasis at diagnosis and 53% at relapse. Metastasis sites were lungs 60%, regional lymph nodes (LNs) 41%, bone 36%, distant LNs 21%, liver 17%, and brain 8%. IMDC risk was 18% good, 48% intermediate, 17% poor, and 17% unknown. Front-line therapy was IO/IO in 21%, IO/TKI in 18%, single-agent TKI in 29%, single-agent IO in 6%, and other in 26%. Genetic alterations included VHL in 50%, PBRM1 in 29%, SETD2 in 23%, BAP1 in 16%, and TP53 in 15%. Median follow-up was 2.74yrs (range 0.1-18.6). Overall mPFS with first line therapy was 1.2yrs (95%CI 0.9-1.5). 2-yr OS was 80% (95%CI: 71-86). For pts with a VHL mutation, mPFS was 1.4yrs (95% CI; 0.9-1.8) compared to 0.9yrs (0.5-1.4) for pts without (p=0.38). 2-yr OS for pts with a VHL mutation was 93% (95% CI: 82-97) vs. 68% (95%CI: 54-78) for pts without (p=0.01). No other mutations impacted overall mPFS or 2-yr OS. mPFS for pts treated with IO/IO was 0.6yrs (95%CI 0.3-0.9) vs. 0.9yrs (95%CI 0.5-1.4) for IO/TKI (p=0.09). 2-yr OS for pts treated with IO/IO was 70% (95% CI 44-85) compared to 94% (95% CI 65-99) for IO/TKI (p=0.29). For pts with SETD2 mutations treated with IO/IO, mPFS was 0.7yrs (95%CI 0.3-1.2) vs. 1.4yrs (95%CI 0.8-1.9) for IO/TKI (p=0.01). For pts with BAP1 mutations treated with IO/IO, mPFS was 0.4yrs (95%CI 0.2-1.2) vs. NE (95%CI 0.2-NE) for IO/TKI (p=0.04). The table outlines outcomes by genomic mutation and therapy. Conclusions: VHL mutation was associated with improved 2-yr OS. Pts with SETD2 and BAP1 mutations treated with IO/TKI had improved mPFS, though no differences in OS. [Table: see text]

Molecular profiling of primary uveal melanoma: results of a Polish cohort.

There is no published data regarding the molecular alterations of Polish patients with primary uveal melanoma. We performed whole exome sequencing of 20 primary uveal melanomas (UMs), 10 metastasizing and 10 non-metastasizing cases to identify significant molecular alterations. We detected mutations and copy number variants in the BAP1 gene in 50% (10 cases) of the cases. GNA11 mutations were detected in 50% (10 cases) including nine p.Q209L and one p.R183C. GNAQ mutations gene were detected in 40% (8 cases) and all were p.Q209P. SF3B1, EIF1AX, PLCB4 , and PALB2 mutations were detected in one case each. Genetic aberrations of FBXW7 were detected in 55% of cases, with copy number loss of 10 and missense mutation in one. Gain or loss of copy number was observed in 60%, 60%, and 10% of cases in MYC, MLH1 , and CDKN2A genes, respectively. BAP1 and GNAQ tumor suppressor genes are more often mutated in UM with metastasis, while GNA11 mutations are more frequently detected in non-metastasizing tumors. MYC copy gain was present twice as frequently (80% versus 40%) in cases with versus those without metastases. BAP1 mutation correlated with worse overall survival; while GNA11 mutation and CDKN2A loss correlated with better and worse progression-free survival, respectively. We have confirmed BAP1 prognostic potential and documented frequent MYC amplification in metastasizing cases. Although GNA11 mutation and CDKN2A loss significantly correlated with progression-free survival in our study, our sample size is small. The prognostic significance of GNAQ/GNA11 mutation and CDKN2A loss would require further investigation.

BAP1 is a novel regulator of HIF-1α

BAP1 is a powerful tumor suppressor gene characterized by haplo insufficiency. Individuals carrying germline BAP1 mutations often develop mesothelioma, an aggressive malignancy of the serosal layers covering the lungs, pericardium, and abdominal cavity. Intriguingly, mesotheliomas developing in carriers of germline BAP1 mutations are less aggressive, and these patients have significantly improved survival. We investigated the apparent paradox of a tumor suppressor gene that, when mutated, causes less aggressive mesotheliomas. We discovered that mesothelioma biopsies with biallelic BAP1 mutations showed loss of nuclear HIF-1α staining. We demonstrated that during hypoxia, BAP1 binds, deubiquitylates, and stabilizes HIF-1α, the master regulator of the hypoxia response and tumor cell invasion. Moreover, primary cells from individuals carrying germline BAP1 mutations and primary cells in which BAP1 was silenced using siRNA had reduced HIF-1α protein levels in hypoxia. Computational modeling and co-immunoprecipitation experiments revealed that mutations of BAP1 residues I675, F678, I679, and L691 -encompassing the C-terminal domain-nuclear localization signal- to A, abolished the interaction with HIF-1α. We found that BAP1 binds to the N-terminal region of HIF-1α, where HIF-1α binds DNA and dimerizes with HIF-1β forming the heterodimeric transactivating complex HIF. Our data identify BAP1 as a key positive regulator of HIF-1α in hypoxia. We propose that the significant reduction of HIF-1α activity in mesothelioma cells carrying biallelic BAP1 mutations, accompanied by the significant reduction of HIF-1α activity in hypoxic tissues containing germline BAP1 mutations, contributes to the reduced aggressiveness and improved survival of mesotheliomas developing in carriers of germline BAP1 mutations.

Somatic BAP1 Loss in Ovarian Serous Borderline Tumor and Recurrent Low-grade Serous Carcinoma From a Germline BAP1 Mutation Carrier.

To the Editor: In a recent issue, Dr. Oliva and colleagues proposed the use of the immunohistochemical markers, Claudin-4 and BAP1, to distinguish between low-grade serous neoplasms and peritoneal mesothelioma 1. This article is of particular interest to us, as we have recently published on a cohort of 119 clinically annotated low-grade serous carcinomas, confirmed by central pathology review, with molecular profiling by targeted next-generation sequencing 2. In this cohort, we encountered 1 patient who represents an unusual exception to relying on loss of BAP1 expression to exclude the diagnosis of a low-grade serous neoplasm. This was a 59-yr-old female who underwent comprehensive surgical staging for bilateral ovarian masses. Final pathology revealed a stage IIIC serous borderline tumor involving bilateral ovaries (Fig. 1A), associated with noninvasive peritoneal implants and involvement of pelvic lymph nodes. After 7 yrs, she developed recurrent disease involving the sigmoid colon, in the form of metastatic low-grade serous carcinoma (Fig. 1B). Both primary and recurrent tumors showed a similar immunophenotype, characterized by strong diffuse expression of epithelial/Mullerian markers, including Claudin-4 (Fig. 1C), BerEP4, PAX8, ER, and PR, while negative for markers of mesothelial differentiation, namely, calretinin, and D2-40. Somatic mutational profiling by targeted next-generation sequencing revealed the low-grade serous carcinoma to harbor a BAP1 frameshift mutation (Y241Lfs*2). Germline testing further revealed a heterozygous BAP1 germline mutation (c.1110dupC, p.Met371Hisfs*27). Loss of BAP1 expression by immunohistochemistry in the low-grade serous carcinoma, as well as the prior serous borderline tumor (Fig. 1D), was consistent with bi-allelic inactivation of BAP1 as an early event in the molecular pathogenesis of this case.FIG. 1: Low-grade serous neoplasms associated with germline BAP1 mutation. (A) Ovarian serous borderline tumor showing characteristic hierarchical branching papillae lined by stratified columnar epithelium (inset: ciliated cells observed at high-magnification, consistent with tubal differentiation). (B) Recurrent invasive low-grade serous carcinoma involving muscularis propria of the sigmoid colon, showing infiltrating nests and micropapillae composed of tumor cells with small monotonous nuclei, and scattered psammoma bodies. Immunohistochemical analysis of the serous borderline tumor showing (C) diffuse expression of Claudin-4 and (D) loss of BAP1 expression in tumor cells with retained nuclear staining in non-neoplastic stromal cells.To our knowledge, this represents the first reported case of a BAP1-deficient low-grade serous neoplasm. It illustrates how genetic alterations of oncogenes and tumor suppressor genes are not tissue or disease-specific and emphasizes the importance of applying several cell lineage markers, along with morphologic correlation, for appropriate diagnostic classification of tumor type.

Prognostic Value of BAP1 and Preferentially Expressed Antigen in Melanoma (PRAME) Immunohistochemistry in Uveal Melanomas

Uveal melanoma (UM) is the most common primary intraocular tumor in adults, and despite excellent local control, more than 50% of patients develop and die from metastatic disease. Loss of BAP1 nuclear staining, a surrogate marker of BAP1 mutation, and preferentially expressed antigen in melanoma (PRAME) messenger RNA overexpression, as assessed using qPCR, have previously been shown to correlate with increased metastasis rate in UM. In this study, we demonstrated that UM could be successfully risk-stratified using a combination of BAP1 and PRAME immunohistochemical (IHC) stains. We retrospectively reviewed 318 UM cases with sufficient tissue and performed BAP1 and PRAME IHC to stratify them as BAP1+/PRAME− (group 1, n = 135), BAP1+/PRAME+ (group 2, n = 43), BAP1−/PRAME− (group 3, n = 94), and BAP1−/PRAME+ (group 4, n = 46). Increasing the study risk group on the basis of loss of BAP1 expression and positive PRAME staining was associated with a higher rate of metastasis and disease-specific death and lower metastasis-free survival (MFS) and disease-specific survival (DSS). Among tumors with loss of BAP1 staining, PRAME positivity was associated with shorter MFS (P = .018) and showed a trend toward shorter DSS (P = .061). Among tumors with retained BAP1 staining, PRAME positivity was associated with shorter MFS and DSS (P = .001 and P = .021, respectively). In summary, a combination of BAP1 and PRAME IHC can be used for risk stratification of UMs.

Correlation analysis between renal clear cell carcinoma and BAP1

Renal clear cell carcinoma (ccRCC) is the most typical pathological type of renal carcinoma (RCC), accounting for about 75%. The pathogenesis of ccRCC is a complex process in which multiple factors or multiple gene variations act together and affect each other. With the deepening research of ccRCC and the development of next-generation sequencing, genomics has been recognized and widely used in cancer research. At present, the mutant gene map of renal clear cell carcinoma has been obtained by high-throughput targeted sequencing, in which the mutant gene BAP1 is a typical tumor suppressor gene. Studies have found that the mutation of BAP1 is closely related to the development and progression of ccRCC. BAP1 mutation is ubiquitous in ccRCC, and has attracted more and more scholars' research interest. Fruitful research results have been obtained, which is of great significance for the early diagnosis and targeted therapy of ccRCC. BAP1 may play a protective role in the development of CCRCC, and its mutation is a marker of poor prognosis in CCRCC. The pathogenesis, proliferation, biological activity, clinical stage and prognosis of renal clear cell carcinoma are all related to the expression and function of BAP1. BAP1 plays an important role in the development of renal clear cell carcinoma.

A Novel Glycolysis-Related Signature for Predicting the Prognosis and Immune Infiltration of Uveal Melanoma

Introduction: As the most common aggressive intraocular cancer in adults, uveal melanoma (UVM) threatens the survival and vision of many people. Glycolysis is a novel hallmark of cancer, but the role of glycolysis-related genes in UVM prognosis remains unknown. The purpose of the study was to establish a glycolysis-related gene signature (GRGS) to predict UVM prognosis. Methods: Raw data were obtained from TCGA-UVM and GSE22138 datasets. The GRGS was established by univariate, LASSO, and multivariate Cox regression analyses. Kaplan-Meier survival and time-dependent receiver operating characteristic curves were used to evaluate the predictive ability of the GRGS. The relationships of the GRGS with infiltrating immune cell levels and mutations were analyzed with CIBERSORT and maftools. Results: A novel GRGS (risk score = 0.690861*ISG20 + 0.070991*MET − 0.227520*SDC2 + 0.690223*FBP1 + 0.048008*CLN6 − 0.128520*SDC3) was developed for predicting UVM prognosis. The GRGS had robust predictive stability in UVM. Enrichment annotation suggested that the high-risk group had stronger adaptive immune responses and that the low-risk group had more innate immune cell infiltration. Moreover, BAP1 mutation was related to high risk, and SF3B1 mutation was related to low risk. Conclusions: This study developed and validated a novel GRGS to predict UVM prognosis and immune infiltration. The signature revealed an association between glycolysis-related genes and the tumor microenvironment, providing new insights into the role of glycolysis in UVM.

Histopathologic and proteogenomic heterogeneity reveals features of clear cell renal cell carcinoma aggressiveness.

Clear cell renal cell carcinomas (ccRCCs) represent ∼75% of RCC cases and account for most RCC-associated deaths. Inter- and intratumoral heterogeneity (ITH) results in varying prognosis and treatment outcomes. To obtain the most comprehensive profile of ccRCC, we perform integrative histopathologic, proteogenomic, and metabolomic analyses on 305 ccRCC tumor segments and 166 paired adjacent normal tissues from 213 cases. Combining histologic and molecular profiles reveals ITH in 90% of ccRCCs, with 50% demonstrating immune signature heterogeneity. High tumor grade, along with BAP1 mutation, genome instability, increased hypermethylation, and a specific protein glycosylation signature define a high-risk disease subset, where UCHL1 expression displays prognostic value. Single-nuclei RNA sequencing of the adverse sarcomatoid and rhabdoid phenotypes uncover gene signatures and potential insights into tumor evolution. Invitro cell line studies confirm the potential of inhibiting identified phosphoproteome targets. This study molecularly stratifies aggressive histopathologic subtypes that may inform more effective treatment strategies.

BAP1 and PTEN mutations shape the immunological landscape of clear cell renal cell carcinoma and reveal the intertumoral heterogeneity of T cell suppression: a proof-of-concept study

Clear cell renal cell carcinoma (ccRCC) is an immunologically vulnerable tumor entity, and immune checkpoint inhibitors are now widely used to treat patients with advanced disease. Whether and to what extent immune responses in ccRCC are shaped by genetic alterations, however, is only beginning to emerge. In this proof-of-concept study, we performed a detailed correlative analysis of the mutational and immunological landscapes in a series of 23 consecutive kidney cancer patients. We discovered that a high infiltration with CD8 + T cells was not dependent on the number of driver mutations but rather on the presence of specific mutational events, namely pathogenic mutations in PTEN or BAP1. This observation encouraged us to compare mechanisms of T cell suppression in the context of four different genetic patterns, i.e., the presence of multiple drivers, a PTEN or BAP1 mutation, or the absence of detectable driver mutations. We found that ccRCCs harboring a PTEN or BAP1 mutation showed the lowest level of Granzyme B positive tumor-infiltrating lymphocytes (TILs). A multiplex immunofluorescence analysis revealed a significant number of CD8 + TILs in the vicinity of CD68 + macrophages/monocytes in the context of a BAP1 mutation but not in the context of a PTEN mutation. In line with this finding, direct interactions between CD8 + TILs and CD163 + M2-polarized macrophages were found in BAP1-mutated ccRCC but not in tumors with other mutational patterns. While an absence of driver mutations was associated with more CD8 + TILs in the vicinity of FOXP3 + Tregs and CD68 + monocytes/macrophages, the presence of multiple driver mutations was, to our surprise, not found to be strongly associated with immunosuppressive mechanisms. Our results highlight the role of genetic alterations in shaping the immunological landscape of ccRCC. We discovered a remarkable heterogeneity of mechanisms that can lead to T cell suppression, which supports the need for personalized immune oncological approaches.

Hybrid Metabolic Activity-Related Prognostic Model and Its Effect on Tumor in Renal Cell Carcinoma.

Tumor cells with a hybrid metabolic state, in which glycolysis and oxidative phosphorylation (OXPHOS) can be used, usually have a strong ability to adapt to different stress environments due to their metabolic plasticity. However, few studies on tumor cells with this phenotype have been conducted in the field of renal cell carcinoma (RCC). The metabolic pathway (glycolysis, OXPHOS) related gene sets were obtained from the Molecular Signatures Database (V7.5.1). The gene expression matrix, clinical information, and mutation data were obtained by Perl programming language (5.32.0) mining, the Cancer Genome Atlas and International Cancer Genome Consortium database. Gene Set Enrichment Analysis (GSEA) software (4.0.3) was utilised to analyse glycolysis-related gene sets. Analysis of survival, immune infiltration, mutation, etc. was performed using the R programming language (4.1.0). Eight genes that are highly associated with glycolysis and OXHPOS were used to construct the cox proportional hazards model, and risk scores were calculated based on this to predict the prognosis of clear cell RCC patients and to classify patients into risk groups. Gene Ontology, the Kyoto Encyclopaedia of Genes and Genomes, and GSEA were analysed according to the differential genes to investigate the signal pathways related to the hybrid metabolic state. Immunoinfiltration analysis revealed that CD8+T cells, M2 macrophages, etc., had significant differences in infiltration. In addition, the analysis of mutation data showed significant differences in the number of mutations of PBRM1, SETD2, and BAP1 between groups. Cell experiments demonstrated that the DLD gene expression was abnormally high in various tumor cells and is associated with the strong migration ability of RCC. We successfully constructed a risk score system based on glycolysis and OXPHOS-related genes to predict the prognosis of RCC patients. Bioinformatics analysis and cell experiments also revealed the effect of the hybrid metabolic activity on the migration ability and immune activity of RCC and the possible therapeutic targets for patients.

BAP1-Inactivated Melanoma Arising From BAP1-Inactivated Melanocytic Tumor in a Patient With BAP1 Germline Mutation: A Case Report and Review of the Literature.

BAP1-inactivated melanocytic tumors represent a subset of epithelioid melanocytic neoplasms resulting from biallelic inactivation of the BAP1 gene and by a driver mutation that activate the MAP kinase pathway, most commonly BRAFV600E. They occur sporadically or, less common, in the setting of BAP1 tumor predisposition syndrome caused by a BAP1 germline mutation that predisposes to several malignancies including cutaneous and uveal melanoma. To date, only few cases of BAP1-inactivated melanomas have been reported. We present a case of a 35-year-old woman presented with a melanocytic lesion microscopically composed of 3 distinct melanocytic populations, suggesting a stepwise progression model to melanoma from a conventional nevus through a melanocytoma stage. This progression was also supported from a molecular viewpoint given BRAFV600E, BAP1, and TERT-p hot spot mutations detected by targeted mutational analysis. Four atypical melanocytic lesions were removed from the patient's back, and the same A BAP1 c.856A>T, p.(Lys286Ter) mutation was detected on either tumoral or normal tissue samples. To the best of our knowledge, this is the first case of BAP1-inactivated melanoma with a documented TERT-p hot spot mutation manifesting as the first presentation of BAP1 tumor predisposition syndrome.

Mapping single-cell transcriptomes in the intra-tumoral and associated territories of kidney cancer.

Tumor behavior is intricately dependent on the oncogenic properties of cancer cells and their multi-cellular interactions. To understand these dependencies within the wider microenvironment, we studied over 270,000 single-cell transcriptomes and 100 microdissected whole exomes from 12 patients with kidney tumors, prior to validation using spatial transcriptomics. Tissues were sampled from multiple regions of the tumor core, the tumor-normal interface, normal surrounding tissues, and peripheral blood. We find that the tissue-type location of CD8+ Tcell clonotypes largely defines their exhaustion state with intra-tumoral spatial heterogeneity that is not well explained by somatic heterogeneity. De novo mutation calling from single-cell RNA-sequencing data allows us to broadly infer the clonality of stromal cells and lineage-trace myeloid cell development. We report six conserved meta-programs that distinguish tumor cell function, and find an epithelial-mesenchymal transition meta-program highly enriched at the tumor-normal interface that co-localizes with IL1B-expressing macrophages, offering a potential therapeutic target.

Genetic heterogeneity of liver cancer stem cells.

Cancer cell heterogeneity is a serious problem in the control of tumor progression because it can cause chemoresistance and metastasis. Heterogeneity can be generated by various mechanisms, including genetic evolution of cancer cells, cancer stem cells (CSCs), and niche heterogeneity. Because the genetic heterogeneity of CSCs has been poorly characterized, the genetic mutation status of CSCs was examined using Exome-Seq and RNA-Seq data of liver cancer. Here we show that different surface markers for liver cancer stem cells (LCSCs) showed a unique propensity for genetic mutations. Cluster of differentiation 133 (CD133)-positive cells showed frequent mutations in the IRF2, BAP1, and ERBB3 genes. However, leucine-rich repeat-containing G protein-coupled receptor 5-positive cells showed frequent mutations in the CTNNB1, RELN, and ROBO1 genes. In addition, some genetic mutations were frequently observed irrespective of the surface markers for LCSCs. BAP1 mutations was frequently observed in CD133-, CD24-, CD13-, CD90-, epithelial cell adhesion molecule-, or keratin 19-positive LCSCs. ASXL2, ERBB3, IRF2, TLX3, CPS1, and NFATC2 mutations were observed in more than three types of LCSCs, suggesting that common mechanisms for the development of these LCSCs. The present study provides genetic heterogeneity depending on the surface markers for LCSCs. The genetic heterogeneity of LCSCs should be considered in the development of LCSC-targeting therapeutics.

Human Metastatic Cholangiocarcinoma Patient-Derived Xenografts and Tumoroids for Preclinical Drug Evaluation.

Cholangiocarcinoma (CCA) is usually diagnosed at advanced stages, with limited therapeutic options. Preclinical models focused on unresectable metastatic CCA are necessary to develop rational treatments. Pathogenic mutations in IDH1/2, ARID1A/B, BAP1, and BRCA1/2 have been identified in 30%-50% of patients with CCA. Several types of tumor cells harboring these mutations exhibit homologous recombination deficiency (HRD) phenotype with enhanced sensitivity to PARP inhibitors (PARPi). However, PARPi treatment has not yet been tested for effectiveness in patient-derived models of advanced CCA. We have established a collection of patient-derived xenografts from patients with unresectable metastatic CCA (CCA_PDX). The CCA_PDXs were characterized at both histopathologic and genomic levels. We optimized a protocol to generate CCA tumoroids from CCA_PDXs. We tested the effects of PARPis in both CCA tumoroids and CCA_PDXs. Finally, we used the RAD51 assay to evaluate the HRD status of CCA tissues. This collection of CCA_PDXs recapitulates the histopathologic and molecular features of their original tumors. PARPi treatments inhibited the growth of CCA tumoroids and CCA_PDXs with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1. In line with these findings, only CCA_PDX and CCA patient biopsy samples with mutations of BRCA2 showed RAD51 scores compatible with HRD. Our results suggest that patients with advanced CCA with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1, are likely to benefit from PARPi therapy. This collection of CCA_PDXs provides new opportunities for evaluating drug response and prioritizing clinical trials.

PBRM1 and BAP1: novel genetic mutations in malignant transformation of craniopharyngioma-a case report.

Malignant craniopharyngioma is especially rare, so the causes and genetic mutations associated with the malignant transformation have not been explained in detail. We investigated the molecular genetic characteristics of malignant transformation in craniopharyngioma. A 53-year-old man with a history of adamantinomatous craniopharyngioma presented with complaints of subcutaneous swelling. Magnetic resonance imaging showed a less enhanced intradural supra-sellar lesion and a heterogeneously well-enhanced extradural invasive lesion infiltrating the dura mater, brain, frontal bone, and subcutaneous tissue. Histopathological examination of the recurrent tumor revealed typical findings of both craniopharyngioma (intradural supra-sellar lesion) and malignant transformation, such as marked nuclear atypia with mitosis (invasive extradural lesion), which were not present in the primary tumor. A genetic panel test with the Oncopanel system was performed to investigate the genetic mutations responsible for the malignant transformation. Four genetic mutations were identified: CTNNB1 c.C98T, TP53 p.C135fs*35(PLS = 3 UPD/LOH), PBRM1 p.R1000*(PLS = 3 UPD/LOH), and BAP1 p.L650fs*5(PLS = 3 UPD/LOH). Sanger sequencing showed CTNNB1 in both the intradural supra-sellar and extradural invasive lesions, but TP53, PBRM1, and BAP1 only in the extradural invasive lesion. The genetic mutations of PBRM1 and BAP1 may be genetic factors in the malignant transformation of adamantinomatous craniopharyngioma.

Viral Mimicry Response Is Associated With Clinical Outcome in Pleural Mesothelioma

IntroductionThe aim of this study was to investigate endogenous retrovirus (ERV) expression and type I interferon (IFN) activation in human pleural mesothelioma (PM) and their association with clinical outcome. MethodsThe expression of ERV was determined from PM cohorts and mesothelial precursor RNA sequencing data. The expression of ERV was confirmed by quantitative polymerase chain reaction (qPCR). Methylation of genomic DNA was assessed by quantitative methylation-specific PCR. DNA demethylation was induced in cells by demethylating agent 5-Aza-2’-deoxycytidine (5-Aza-CdR) treatment. To block type I IFN signaling, the cells were treated with ruxolitinib or MAVS silencing. The expression of IFN-stimulated genes (ISGs) was determined by qPCR and Western blot. Circulating ERVs were detected by qPCR. ResultsLong terminal repeats (LTRs) represent the most abundant transposable elements up-regulated in PM. Within the LTR, ERVmap_1248 and LTR7Y, which are specifically enriched in PM, were further analyzed. The 5-Aza-CdR treatment increased the levels of ERVmap_1248 expression and induced ERVmap_1248 promoter demethylation in mesothelial cells. In addition, ERVmap_1248 promoter was more demethylated in the mesothelioma tissue compared with nontumor tissue. The 5-Aza-CdR treatment of the mesothelial cells also increased the levels of ISGs. Basal ISG expression was higher in the mesothelioma cells compared with the mesothelial cells, and it was significantly decreased by ruxolitinib treatment or MAVS silencing. Furthermore, ISG expression was higher in the tumor tissue with high expression levels of ERVmap_1248. High expression of ERVmap_1248 was associated with longer overall survival and BAP1 mutations. ERVmap_1248 and LTR7Y can be detected in the PM plasma. ConclusionsWe provide clues for patient stratification especially for immunotherapy where best clinical responses are associated with an activated basal immune response.

89 (PB079) - Preliminary Clinical Data From Ongoing Phase 2 Study With Enhancer of Zeste Homolog 2 (EZH2) Inhibitor CPI-0209 in Patients With Advanced Solid Tumors or Hematologic Malignancies

Background: Enhancer of zeste homolog 2 (EZH2) is a histone-lysine N-methyltransferase enzyme and the catalytic subunit of polycomb repressive complex 2. ARID1A mutations have been linked to increased sensitivity to EZH2 inhibition. Inactivating BAP1 mutations in mesothelioma have been linked to dependency on EZH2 function. CPI-0209 is an investigative oral, small-molecule, second-generation, selective EZH2 inhibitor that shows durable and comprehensive target coverage based on findings in Phase 1 (NCT04104776; Lakhani, et al.

Unraveling tumor microenvironment heterogeneity in malignant pleural mesothelioma identifies biologically distinct immune subtypes enabling prognosis determination.

BackgroundMalignant pleural mesothelioma (MPM) is a rare and intractable disease exhibiting a remarkable intratumoral heterogeneity and dismal prognosis. Although immunotherapy has reshaped the therapeutic strategies for MPM, patients react with discrepant responsiveness.MethodsHerein, we recruited 333 MPM patients from 5 various cohorts and developed an in-silico classification system using unsupervised Non-negative Matrix Factorization and Nearest Template Prediction algorithms. The genomic alterations, immune signatures, and patient outcomes were systemically analyzed across the external TCGA-MESO samples. Machine learning-based integrated methodology was applied to identify a gene classifier for clinical application.ResultsThe gene expression profiling-based classification algorithm identified immune-related subtypes for MPMs. In comparison with the non-immune subtype, we validated the existence of abundant immunocytes in the immune subtype. Immune-suppressed MPMs were enriched with stroma fraction, myeloid components, and immunosuppressive tumor-associated macrophages (TAMs) as well exhibited increased TGF-β signature that informs worse clinical outcomes and reduced efficacy of anti-PD-1 treatment. The immune-activated MPMs harbored the highest lymphocyte infiltration, growing TCR and BCR diversity, and presented the pan-cancer immune phenotype of IFN-γ dominant, which confers these tumors with better drug response when undergoing immune checkpoint inhibitor (ICI) treatment. Genetically, BAP1 mutation was most commonly found in patients of immune-activated MPMs and was associated with a favorable outcome in a subtype-specific pattern. Finally, a robust 12-gene classifier was generated to classify MPMs with high accuracy, holding promise value in predicting patient survival.ConclusionsWe demonstrate that the novel classification system can be exploited to guide the identification of diverse immune subtypes, providing critical biological insights into the mechanisms driving tumor heterogeneity and responsible for cancer-related patient prognoses.

The convergence of tumor suppressors on the type I interferon pathway in clear cell renal cell carcinoma and its therapeutic implications.

In clear cell renal cell carcinoma (ccRCC), the von Hippel-Lindau tumor suppressor gene/hypoxia inducible factor (VHL/HIF) axis lays the groundwork for tumorigenesis and is the target of many therapeutic agents. HIF activation alone, however, is largely insufficient for kidney tumor development, and secondary mutations in PBRM1, BAP1, SETD2, KDM5C, or other tumor suppressor genes are strong enablers of tumorigenesis. Interestingly, it has been discovered that VHL loss and subsequent HIF activation results in upregulation of a negative feedback loop mediated by ISGF3, a transcription factor activated by type I interferon (IFN). Secondary mutations in the aforementioned tumor suppressor genes all partially disable this negative feedback loop to facilitate tumor growth. The convergence of several cancer genes on this pathway suggests that it plays an important role in ccRCC development and maintenance. Tumors with secondary mutations that dampen the negative feedback loop may be exquisitely sensitive to its reactivation, and pharmacological activation of ISGF3 either alone or in combination with other therapies could be an effective method to treat patients with ccRCC. In this review, we examine the relevance of the type I IFN pathway to ccRCC, synthesize our current knowledge of the ccRCC tumor suppressors in its regulation, and explore how this may impact the future treatment of patients with ccRCC.

Integrative Analysis Identifies TCIRG1 as a Potential Prognostic and Immunotherapy-Relevant Biomarker Associated with Malignant Cell Migration in Clear Cell Renal Cell Carcinoma.

Simple SummaryTCIRG1, also known as V-ATPase-a3, is critical for cellular metabolism, membrane transport, and intracellular signaling through its dependent acidification. In earlier research, TCIRG1 was found to be dysregulated in several cancers and to accelerate the growth of various malignancies. The molecular mechanisms behind TCIRG1 and its possible role in the development of clear cell renal cell carcinoma are still poorly understood. Our research is the first to thoroughly examine TCIRG1’s function in clear cell renal cell carcinoma prognosis, immunity, and treatment. The validity that TCIRG1 can accelerate the development of renal clear cell carcinoma was also confirmed in this work by using certain testable experiments. This establishes the theoretical framework for our future investigation into the occurrence and progression of clear cell renal cell carcinoma.Background: TCIRG1, also known as V-ATPase-a3, is critical for cellular life activities through its dependent acidification. Prior to the present research, its relationship with prognostic and tumor immunity in clear cell renal cell carcinoma (ccRCC) had not yet been investigated. Methods: We assessed TCIRG1 expression in normal and tumor tissues using data from TCGA, GEO, GTEX, and IHC. We also analyzed the relationship between TCIRG1 and somatic mutations, TMB, DNA methylation, cancer stemness, and immune infiltration. We evaluated the relevance of TCIRG1 to immunotherapy and potential drugs. Finally, we explored the effect of TCIRG1 knockdown on tumor cells. Results: TCIRG1 was overexpressed in tumor tissue and predicted a significantly unfavorable clinical outcome. High TCIRG1 expression may be associated with fewer PBRM1 and more BAP1 mutations and may reduce DNA methylation, thus leading to a poor prognosis. TCIRG1 was strongly associated with CD8+ T-cell, Treg, and CD4+ T-cell infiltration. Moreover, TCIRG1 was positively correlated with TIDE scores and many drug sensitivities. Finally, experiments showed that the knockdown of TCIRG1 inhibited the migration of ccRCC cells. Conclusions: TCIRG1 may have great potential in identifying prognostic and immunomodulatory mechanisms in tumor patients and may provide a new therapeutic strategy for ccRCC.