Frequent ZNF217 mutations lead to transcriptional deregulation of interferon signal transduction via altered chromatin accessibility in B cell lymphoma.

Recent exome-wide studies discovered frequent somatic mutations in the epigenetic modifier ZNF217 in primary mediastinal B cell lymphoma (PMBCL) and related disorders. As functional consequences of ZNF217 alterations remain unknown, we comprehensively evaluated their impact in PMBCL. Targeted sequencing identified genetic lesions affecting ZNF217 in 33% of 157 PMBCL patients. Subsequent gene expression profiling (n = 120) revealed changes in cytokine and interferon signal transduction in ZNF217-aberrant PMBCL cases. In vitro, knockout of ZNF217 led to changes in chromatin accessibility interfering with binding motifs for crucial lymphoma-associated transcription factors. This led to disturbed expression of interferon-responsive and inflammation-associated genes, altered cell behavior, and aberrant differentiation. Mass spectrometry demonstrates that ZNF217 acts within a histone modifier complex containing LSD1, CoREST and HDAC and interferes with H3K4 methylation and H3K27 acetylation. Concluding, our data suggest non-catalytic activity of ZNF217, which directs histone modifier complex function and controls B cell differentiation-associated patterns of chromatin structure.

Differential ion mobility mass spectrometry in immunopeptidomics identifies neoantigens carrying colorectal cancer driver mutations.

Understanding the properties of human leukocyte antigen (HLA) peptides (immunopeptides) is essential for precision cancer medicine, while the direct identification of immunopeptides from small biopsies of clinical tissues by mass spectrometry (MS) is still confronted with technical challenges. Here, to overcome these hindrances, high-field asymmetric waveform ion mobility spectrometry (FAIMS) is introduced to conduct differential ion mobility (DIM)-MS by seamless gas-phase fractionation optimal for scarce samples. By established DIM-MS for immunopeptidomics analysis, on average, 42.9 mg of normal and tumor colorectal tissues from identical patients (n = 17) were analyzed, and on average 4921 immunopeptides were identified. Among these 44,815 unique immunopeptides, two neoantigens, KRAS-G12V and CPPED1-R228Q, were identified. These neoantigens were confirmed by synthetic peptides through targeted MS in parallel reaction monitoring (PRM) mode. Comparison of the tissue-based personal immunopeptidome revealed tumor-specific processing of immunopeptides. Since the direct identification of neoantigens from tumor tissues suggested that more potential neoantigens have yet to be identified, we screened cell lines with known oncogenic KRAS mutations and identified 2 more neoantigens that carry KRAS-G12V. These results indicated that the established FAIMS-assisted DIM-MS is effective in the identification of immunopeptides and potential recurrent neoantigens directly from scarce samples such as clinical tissues.

The landscape of genetic aberrations in myxofibrosarcoma.

Myxofibrosarcoma (MFS) is a rare subtype of sarcoma, whose genetic basis is poorly understood. We analyzed 69 MFS cases using whole-genome (WGS), whole-exome (WES) and/or targeted-sequencing (TS). Newly sequenced genomic data were combined with additional deposited 116 MFS samples. WGS identified a high number of structural variations (SVs) per tumor most frequently affecting the TP53 and RB1 loci, 40% of tumors showed a BRCAness-associated mutation signature, and evidence of chromothripsis was found in all cases. Most frequently mutated/copy number altered genes affected known disease drivers such as TP53 (56.2%), CDKN2A/B (29.7%), RB1 (27.0%), ATRX (19.5%) and HDLBP (18.9%). Several previously unappreciated genetic aberrations including MUC17, FLG and ZNF780A were identified in more than 20% of patients. Longitudinal analysis of paired diagnosis and relapse time points revealed a 1.2-fold mutation number increase accompanied with substantial changes in clonal composition over time. Our study highlights the genetic complexity underlying sarcomagenesis of MFS.

Molecular classification and diagnostics of upper urinary tract urothelial carcinoma.

Upper urinary tract urothelial carcinoma (UTUC) is one of the common urothelial cancers. Its molecular pathogenesis, however, is poorly understood, with no useful biomarkers available for accurate diagnosis and molecular classification. Through an integrated genetic study involving 199 UTUC samples, we delineate the landscape of genetic alterations in UTUC enabling genetic/molecular classification. According to the mutational status of TP53, MDM2, RAS, and FGFR3, UTUC is classified into five subtypes having discrete profiles of gene expression, tumor location/histology, and clinical outcome, which is largely recapitulated in an independent UTUC cohort. Sequencing of urine sediment-derived DNA has a high diagnostic value for UTUC with 82.2% sensitivity and 100% specificity. These results provide a solid basis for better diagnosis and management of UTUC.

Frequent genetic alterations in immune checkpoint-related genes in intravascular large B-cell lymphoma.

Intravascular large B-cell lymphoma (IVLBCL) is a unique type of extranodal lymphoma characterized by selective growth of tumor cells in small vessels without lymphadenopathy. Greater understanding of the molecular pathogenesis of IVLBCL is hampered by the paucity of lymphoma cells in biopsy specimens, creating a limitation in obtaining sufficient tumor materials. To uncover the genetic landscape of IVLBCL, we performed whole-exome sequencing (WES) of 21 patients with IVLBCL using plasma-derived cell-free DNA (cfDNA) (n = 18), patient-derived xenograft tumors (n = 4), and tumor DNA from bone marrow (BM) mononuclear cells (n = 2). The concentration of cfDNA in IVLBCL was significantly higher than that in diffuse large B-cell lymphoma (DLBCL) (P < .0001) and healthy donors (P = .0053), allowing us to perform WES; most mutations detected in BM tumor DNA were successfully captured in cfDNA and xenograft. IVLBCL showed a high frequency of genetic lesions characteristic of activated B-cell-type DLBCL, with the former showing conspicuously higher frequencies (compared with nodal DLBCL) of mutations in MYD88 (57%), CD79B (67%), SETD1B (57%), and HLA-B (57%). We also found that 8 IVLBCL (38%) harbored rearrangements of programmed cell death 1 ligand 1 and 2 (PD-L1/PD-L2) involving the 3' untranslated region; such rearrangements are implicated in immune evasion via PD-L1/PD-L2 overexpression. Our data demonstrate the utility of cfDNA and imply important roles for immune evasion in IVLBCL pathogenesis and PD-1/PD-L1/PD-L2 blockade in therapeutics for IVLBCL.

Unbiased Detection of Driver Mutations in Extramammary Paget Disease.

PURPOSE: Extramammary Paget disease (EMPD) is an uncommon skin malignancy whose genetic alterations are poorly characterized. Previous reports identified mutations in chromatin remodeling genes and PIK3CA. In order to unambiguously determine driver mutations in EMPD, we analyzed 87 EMPD samples using exome sequencing in combination with targeted sequencing. EXPERIMENTAL DESIGN: First, we analyzed 37 EMPD samples that were surgically resected using whole-exome sequencing. Based on several in silico analysis, we built a custom capture panel of putative driver genes and analyzed 50 additional formalin-fixed, paraffin-embedded samples using target sequencing. ERBB2 expression was evaluated by HER2 immunohisotochemistry. Select samples were further analyzed by fluorescence in situ hybridization. RESULTS: A median of 92 mutations/sample was identified in exome analysis. A union of driver detection algorithms identified ERBB2, ERBB3, KMT2C, TP53, PIK3CA, NUP93, AFDN, and CUX1 as likely driver mutations. Copy-number alteration analysis showed regions spanning CDKN2A as recurrently deleted, and ERBB2 as recurrently amplified. ERBB2, ERBB3, and FGFR1 amplification/mutation showed tendency toward mutual exclusivity. Copy-number alteration load was associated with likelihood to recur. Mutational signatures were dominated by aging and APOBEC activation and lacked evidence of ultraviolet radiation. HER2 IHC/fluorescence in situ analysis validated ERBB2 amplification but was underpowered to detect mutations. Tumor heterogeneity in terms of ERBB2 amplification status was observed in some cases. CONCLUSIONS: Our comprehensive, unbiased analysis shows EMPD is characterized by alterations involving the PI3K-AKT pathway. EMPD is distinct from other skin cancers in both molecular pathways altered and etiology behind mutagenesis.

Genetic and clinical landscape of breast cancers with germline BRCA1/2 variants.

The genetic and clinical characteristics of breast tumors with germline variants, including their association with biallelic inactivation through loss-of-heterozygosity (LOH) and second somatic mutations, remain elusive. We analyzed germline variants of 11 breast cancer susceptibility genes for 1,995 Japanese breast cancer patients, and identified 101 (5.1%) pathogenic variants, including 62 BRCA2 and 15 BRCA1 mutations. Genetic analysis of 64 BRCA1/2-mutated tumors including TCGA dataset tumors, revealed an association of biallelic inactivation with more extensive deletions, copy neutral LOH, gain with LOH and younger onset. Strikingly, TP53 and RB1 mutations were frequently observed in BRCA1- (94%) and BRCA2- (9.7%) mutated tumors with biallelic inactivation. Inactivation of TP53 and RB1 together with BRCA1 and BRCA2, respectively, involved LOH of chromosomes 17 and 13. Notably, BRCA1/2 tumors without biallelic inactivation were indistinguishable from those without germline variants. Our study highlights the heterogeneity and unique clonal selection pattern in breast cancers with germline variants.

Frequent mutations that converge on the NFKBIZ pathway in ulcerative colitis.

Chronic inflammation is accompanied by recurring cycles of tissue destruction and repair and is associated with an increased risk of cancer1-3. However, how such cycles affect the clonal composition of tissues, particularly in terms of cancer development, remains unknown. Here we show that in patients with ulcerative colitis, the inflamed intestine undergoes widespread remodelling by pervasive clones, many of which are positively selected by acquiring mutations that commonly involve the NFKBIZ, TRAF3IP2, ZC3H12A, PIGR and HNRNPF genes and are implicated in the downregulation of IL-17 and other pro-inflammatory signals. Mutational profiles vary substantially between colitis-associated cancer and non-dysplastic tissues in ulcerative colitis, which indicates that there are distinct mechanisms of positive selection in both tissues. In particular, mutations in NFKBIZ are highly prevalent in the epithelium of patients with ulcerative colitis but rarely found in both sporadic and colitis-associated cancer, indicating that NFKBIZ-mutant cells are selected against during colorectal carcinogenesis. In further support of this negative selection, we found that tumour formation was significantly attenuated in Nfkbiz-mutant mice and cell competition was compromised by disruption of NFKBIZ in human colorectal cancer cells. Our results highlight common and discrete mechanisms of clonal selection in inflammatory tissues, which reveal unexpected cancer vulnerabilities that could potentially be exploited for therapeutics in colorectal cancer.

Age-related remodelling of oesophageal epithelia by mutated cancer drivers.

Clonal expansion in aged normal tissues has been implicated in the development of cancer. However, the chronology and risk dependence of the expansion are poorly understood. Here we intensively sequence 682 micro-scale oesophageal samples and show, in physiologically normal oesophageal epithelia, the progressive age-related expansion of clones that carry mutations in driver genes (predominantly NOTCH1), which is substantially accelerated by alcohol consumption and by smoking. Driver-mutated clones emerge multifocally from early childhood and increase their number and size with ageing, and ultimately replace almost the entire oesophageal epithelium in the extremely elderly. Compared with mutations in oesophageal cancer, there is a marked overrepresentation of NOTCH1 and PPM1D mutations in physiologically normal oesophageal epithelia; these mutations can be acquired before late adolescence (as early as early infancy) and significantly increase in number with heavy smoking and drinking. The remodelling of the oesophageal epithelium by driver-mutated clones is an inevitable consequence of normal ageing, which-depending on lifestyle risks-may affect cancer development.

Integrated Molecular Characterization of the Lethal Pediatric Cancer Pancreatoblastoma.

Pancreatoblastoma is a rare pediatric pancreatic malignancy for which the molecular pathogenesis is not understood. In this study, we report the findings of an integrated multiomics study of whole-exome and RNA sequencing as well as genome-wide copy number and methylation analyses of ten pancreatoblastoma cases. The pancreatoblastoma genome was characterized by a high frequency of aberrant activation of the Wnt signaling pathway, either via somatic mutations of CTNNB1 (90%) and copy-neutral loss of heterozygosity (CN-LOH) of APC (10%). In addition, imprinting dysregulation of IGF2 as a consequence of CN-LOH (80%), gain of paternal allele (10%), and gain of methylation (10%) was universally detected. At the transcriptome level, pancreatoblastoma exhibited an expression profile characteristic of early pancreas progenitor-like cells along with upregulation of the R-spondin/LGR5/RNF43 module. Our results offer a comprehensive description of the molecular basis for pancreatoblastoma and highlight rational therapeutic targets for its treatment.Significance: Molecular genetic analysis of a rare untreatable pediatric tumor reveals Wnt/IGF2 aberrations and features of early pancreas progenitor-like cells, suggesting cellular origins and rational strategies for therapeutic targeting. Cancer Res; 78(4); 865-76. ©2017 AACR.

Laparoscopy endoscopy cooperative surgery for gastric plexiform fibromyxoma: a case report.

BACKGROUND: Gastric submucosal tumors are commonly treated by partial resection under laparoscopy. However, the surgical resection of gastric submucosal tumors sometimes causes deformation of the stomach, especially in the case of intraluminal tumors located near the pylorus or esophagogastric junction. Such deformations can result in impaired diet intake and reduced quality of life. Laparoscopic endoscopic cooperative surgery has been developed to overcome these problems. This is the first report to describe a case of gastric plexiform fibromyxoma, a rare gastric submucosal tumor, that was successfully resected by laparoscopic endoscopic cooperative surgery. CASE PRESENTATION: A 36-year-old Japanese woman presented with epigastric pain and anemia. Gastrointestinal endoscopy revealed a submucosal tumor in the gastric antrum. Because a definitive diagnosis could not be obtained and the tumor was located near the pylorus, we performed laparoscopic endoscopic cooperative surgery as diagnostic therapy. The postoperative course was favorable with no complications, such as delayed gastric emptying or outlet obstruction. The tumor was pathologically diagnosed as gastric plexiform fibromyxoma. CONCLUSIONS: Laparoscopic endoscopic cooperative surgery is a useful approach for diagnostic therapy for rare submucosal tumors to avoid the deformation of the stomach, especially when the tumor is located near the pylorus.

[Hepatic resection for local recurrence after radiofrequency ablation therapy for colorectal liver metastases].

Patients who underwent hepatic resection of locally recurrent tumors after radiofrequency ablation(RFA)for colorectal liver metastases (CRLM) were retrospectively investigated. Among 12 patients who underwent RFA as first-line treatment for CRLM, 7 experienced local recurrence, 5 of whom (6 nodules) underwent hepatic resection. The mean diameter (range) of the tumors was 9.5(5-16) mm, and they were located at S2, S7 (adjacent to the right hepatic vein), S5/6 (between the root of the anterior and the posterior Glisson's pedicle), S1r (right paracaval portion), S6, and S3. No local recurrence was observed after hepatic resection. In conclusion, hepatic resection must be the initial therapeutic strategy for CRLM, and the indication for RFA must be considered carefully.

[A case of lung metastases of carcinoma of the ampulla of vater effectively treated with S-1].

A 70-year-old female patient underwent pylorus-preserving pancreaticoduodenectomy for carcinoma of the ampulla of Vater in March 2007. In April 2009, multiple lung metastases were detected by CT scanning. The patient was treated with S-1 (80mg/day, day 1-28, followed by 2-weeks withdrawal)from April 2009. The shrinkage of lung metastases was diagnosed as a complete response based on the Response Evaluation Criteria in Solid Tumors(RECIST). No severe toxicities were observed. S-1 is an effective and safe anti-cancer agent available for lung metastases of carcinoma of the ampulla of Vater.