Incidence and natural history of gastric high-grade dysplasia in patients with familial adenomatous polyposis syndrome.

BACKGROUND AND AIMS: Familial adenomatous polyposis (FAP) is characterized by high risks of colonic and extracolonic tumors. Recent studies have suggested a rising risk for gastric cancer (GC). We sought to define the spectrum of premalignant gastric polyps in FAP, focusing on high-grade dysplasia (HGD). METHODS: The gastric phenotypes of 118 patients diagnosed with FAP or attenuated FAP in our Hereditary Gastrointestinal Cancer Registry were retrospectively reviewed. To analyze the clinical features associated with the diagnosis of HGD, we established an age- and sex-matched control group of FAP patients from our cohort without gastric HGD in a 4:1 ratio. RESULTS: The spectrum and frequency of gastric polyps in individuals with FAP included fundic gland polyps (67.9%), hyperplastic polyps/foveolar hyperplasia (19.6%), tubular adenomas (15.2%), foveolar adenomas (10.7%), and pyloric gland adenomas (6.3%). Ten patients (8.9%) exhibited gastric HGD at a mean age of 55 ± 13 years, and HGD was seen in all polyp types. When compared with control subjects, HGD was associated with a high diversity of gastric polyp histology, prior low-grade dysplasia, severe gastric polyposis, and prior Whipple surgery (P = 2.0E-5, .003, .024, and .04, respectively). Two patients (1.7%) with HGD were diagnosed with GC. However, the remaining 8 patients with HGD have been under surveillance for an average of 5.8 ± 4.5 years without progression to GC. CONCLUSIONS: Gastric HGD in FAP may be more common than previously appreciated. The natural history of HGD is variable, and most patients with HGD do not appear to progress to GC.

BAP1 and Claudin-4, But Not MTAP, Reliably Distinguish Borderline and Low-grade Serous Ovarian Tumors From Peritoneal Mesothelioma.

Peritoneal mesothelioma (PM) and serous neoplasms can be difficult to differentiate, particularly in small biopsies. BRCA1-associated protein 1 (BAP1) is expressed in benign tissues, but over 50% of PMs demonstrate complete loss of nuclear expression. Claudin-4, a tight junction protein, is expressed in most epithelial tumors but not in mesotheliomas. Methylthioadenosine phosphorylase (MTAP) is frequently co-deleted with cyclin-dependent kinase inhibitor 2a in mesotheliomas. These markers have proven useful in separating mesothelioma from its mimics, particularly when tumors are pleural based. In the peritoneum, BAP1 loss has been rarely reported in high-grade serous carcinomas, but overall, these markers have been minimally evaluated in ovarian serous borderline tumors and low-grade serous carcinomas. Thus, we assessed the utility of BAP1, claudin-4, and MTAP in the differential diagnosis of PM and low-grade serous neoplasms. Eighteen PM (16 epithelioid, 1 biphasic, and 1 sarcomatous), 24 low-grade serous carcinomas, and 25 serous borderline tumors were stained for BAP1, claudin-4, and MTAP. Loss of BAP1 nuclear expression was observed in 12 (67%) PM (11 epithelioid, 1 biphasic) but was retained in all serous tumors. Claudin-4 was positive in all serous tumors and negative in all PM. Complete loss of cytoplasmic MTAP was noted in 3 (17%) PMs and 1 (4%) serous borderline tumor, while all low-grade serous carcinomas showed retained expression. BAP1 loss reliably distinguishes PM from serous tumors, although it lacks sensitivity. Claudin-4 is a reliable marker to exclude PM. MTAP loss may occur in both PM and serous tumors, and thus is not useful in distinguishing these entities.

Histiocytic and Dendritic Cell Sarcomas of Hematopoietic Origin Share Targetable Genomic Alterations Distinct from Follicular Dendritic Cell Sarcoma.

BACKGROUND: Histiocytic and dendritic cell neoplasms are a diverse group of tumors arising from monocytic or dendritic cell lineage. Whereas the genomic features for Langerhans cell histiocytosis and Erdheim-Chester disease have been well described, other less common and often aggressive tumors in this broad category remain poorly characterized, and comparison studies across the World Health Organization diagnostic categories are lacking. METHODS: Tumor samples from a total of 102 patient cases within four major subtypes of malignant histiocytic and dendritic cell neoplasms, including 44 follicular dendritic cell sarcomas (FDCSs), 41 histiocytic sarcomas (HSs), 7 interdigitating dendritic cell sarcomas (IDCSs), and 10 Langerhans cell sarcomas (LCSs), underwent hybridization capture with analysis of up to 406 cancer-related genes. RESULTS: Among the entire cohort of 102 patients, CDKN2A mutations were most frequent across subtypes and made up 32% of cases, followed by TP53 mutations (22%). Mitogen-activated protein kinase (MAPK) pathway mutations were present and enriched among the malignant histiocytosis (M) group (HS, IDCS, and LCS) but absent in FDCS (72% vs. 0%; p < .0001). In contrast, NF-κB pathway mutations were frequent in FDCSs but rare in M group histiocytoses (61% vs. 12%; p < .0001). Tumor mutational burden was significantly higher in M group histiocytoses as compared with FDCSs (median 4.0/Mb vs. 2.4/Mb; p = .012). We also describe a pediatric patient with recurrent secondary histiocytic sarcoma treated with targeted therapy and interrogated by molecular analysis to identify mechanisms of therapeutic resistance. CONCLUSION: A total of 42 patient tumors (41%) harbored pathogenic mutations that were potentially targetable by approved and/or investigative therapies. Our findings highlight the potential value of molecular testing to enable precise tumor classification, identify candidate oncogenic drivers, and define personalized therapeutic options for patients with these aggressive tumors. IMPLICATIONS FOR PRACTICE: This study presents comprehensive genomic profiling results on 102 patient cases within four major subtypes of malignant histiocytic and dendritic cell neoplasms, including 44 follicular dendritic cell sarcomas (FDCSs), 41 histiocytic sarcomas (HSs), 7 interdigitating dendritic cell sarcomas (IDCSs), and 10 Langerhans cell sarcomas (LCSs). MAPK pathway mutations were present and enriched among the malignant histiocytosis (M) group (HS, IDCS, and LCS) but absent in FDCSs. In contrast, NF-κB pathway mutations were frequent in FDCSs but rare in M group histiocytosis. A total of 42 patient tumors (41%) harbored pathogenic mutations that were potentially targetable by approved and/or investigative therapies.

Pan-sarcoma genomic analysis of KMT2A rearrangements reveals distinct subtypes defined by YAP1-KMT2A-YAP1 and VIM-KMT2A fusions.

Sarcomas are driven by diverse pathogenic mechanisms, including gene rearrangements in a subset of cases. Rare soft tissue sarcomas containing KMT2A fusions have recently been reported, characterized by a predilection for young adults, sclerosing epithelioid fibrosarcoma-like morphology, and an often aggressive course. Nonetheless, clinicopathologic and molecular descriptions of KMT2A-rearranged sarcomas remain limited. In this study, we identified by targeted next-generation RNA sequencing an index patient with KMT2A fusion-positive soft tissue sarcoma. In addition, we systematically searched for KMT2A structural variants in a comprehensive genomic profiling database of 14,680 sarcomas interrogated by targeted next-generation DNA and/or RNA sequencing. We characterized the clinicopathologic and molecular features of KMT2A fusion-positive sarcomas, including KMT2A breakpoints, rearrangement partners, and concurrent genetic alterations. Collectively, we identified a cohort of 34 sarcomas with KMT2A fusions (0.2%), and YAP1 was the predominant partner (n = 16 [47%]). Notably, a complex rearrangement with YAP1 consistent with YAP1-KMT2A-YAP1 fusion was detected in most cases, with preservation of KMT2A CxxC-binding domain in the YAP1-KMT2A-YAP1 fusion and concurrent deletions of corresponding exons in KMT2A. The tumors often affected younger adults (age 20-66 [median 40] years) and histologically showed variably monomorphic epithelioid-to-spindle shaped cells embedded in a dense collagenous stroma. Ultrastructural evidence of fibroblastic differentiation was noted in one tumor examined. Our cohort also included two sarcomas with VIM-KMT2A fusions, each harboring concurrent mutations in CTNNB1, SMARCB1, and ARID1A and characterized histologically by sheets of spindle-to-round blue cells. The remaining 16 KMT2A-rearranged sarcomas in our cohort exhibited diverse histologic subtypes, each with unique novel fusion partners. In summary, KMT2A-fusion-positive sarcomas most commonly exhibit sclerosing epithelioid fibrosarcoma-like morphology and complex YAP1-KMT2A-YAP1 fusions. Cases also include rare spindle-to-round cell sarcomas with VIM-KMT2A fusions and tumors of diverse histologic subtypes with unique KMT2A fusions to non-YAP1 non-VIM partners.

EMR is superior to rectal suction biopsy for analysis of enteric ganglia in constipation and dysmotility.

BACKGROUND AND AIMS: Patients with chronic constipation or motility disorders may be referred for rectal suction biopsy (RSB) to rule out Hirschsprung's disease (HD). RSB may not be successful beyond infancy because of the increased thickness of the rectal mucosa. EMR could improve the diagnostic yield for HD when compared with traditional RSB because larger and deeper samples are acquired for analysis. METHODS: In this prospective, single-center study, patients referred for RSB were offered enrollment for concurrent EMR. Specimens were analyzed pathologically for size, submucosal ganglionic tissue, and acetylcholinesterase or calretinin staining. Biopsy results were compared with transit studies, anorectal manometry, and constipation severity through validated questionnaires. RESULTS: Seventeen patients (2 male, 15 female; mean age, 35.8 years; range, 22-61 years) were enrolled in the study from 2008 to 2014. All patients underwent anorectal manometry (88% with anorectal dysfunction, 68% with outlet obstruction) and transit studies (41% with delayed transit). There were no reports of adverse events from the RSB and EMR procedures. The RSB sample volumes were significantly lower than the EMR sample volumes (0.023 cm3 vs 0.26 cm3, P = .001). There was diagnostic tissue for submucosal visualization by RSB in 53% (9/17) of cases compared with 100% (17/17) with EMR (P = .003). No cases of HD were diagnosed by RSB; one patient had rare ganglions observed by EMR. CONCLUSIONS: EMR provides greater tissue volume and can improve the characterization of ganglion cells in rectal tissue compared with RSB in patients with moderate to severe constipation with suspected HD.

mTORC1 in the Paneth cell niche couples intestinal stem-cell function to calorie intake.

How adult tissue stem and niche cells respond to the nutritional state of an organism is not well understood. Here we find that Paneth cells, a key constituent of the mammalian intestinal stem-cell (ISC) niche, augment stem-cell function in response to calorie restriction. Calorie restriction acts by reducing mechanistic target of rapamycin complex 1 (mTORC1) signalling in Paneth cells, and the ISC-enhancing effects of calorie restriction can be mimicked by rapamycin. Calorie intake regulates mTORC1 in Paneth cells, but not ISCs, and forced activation of mTORC1 in Paneth cells during calorie restriction abolishes the ISC-augmenting effects of the niche. Finally, increased expression of bone stromal antigen 1 (Bst1) in Paneth cells­an ectoenzyme that produces the paracrine factor cyclic ADP ribose­mediates the effects of calorie restriction and rapamycin on ISC function. Our findings establish that mTORC1 non-cell-autonomously regulates stem-cell self-renewal, and highlight a significant role of the mammalian intestinal niche in coupling stem-cell function to organismal physiology.

Clinicopathological characteristics of systemic mastocytosis in the intestine.

AIMS: Gastrointestinal (GI) involvement by systemic mastocytosis (SM) presents with non-specific symptoms, and pathological diagnosis can be difficult when a subtle mast cell infiltrate is present. The aim of this study was to characterize the clinicopathological features in diagnostically challenging cases. METHODS AND RESULTS: Seven patients with GI biopsies showing an atypical mast cell infiltrate were identified, including three consultation cases in which mast cells were initially overlooked. Clinicopathological characteristics were evaluated. Biopsies showed involvement of the large bowel (n = 5), small bowel (n = 1) or both (n = 1) by a wide morphological spectrum of mast cells, including: bland spindle cells; small cells with irregular nuclei; and medium-sized monotonous cells with abundant pale cytoplasm. The patterns of mucosal involvement included: a polypoid mast cell aggregate (n = 1); a confluent subepithelial band of mast cells (n = 3); and multifocal aggregates of mast cells (n = 3). There were admixed eosinophils with a noticeable lack of plasma cells. Mast cells in all cases showed strong positive staining for CD117 and CD25. All patients fulfilled the World Health Organization (WHO) criteria for SM. On follow-up in four cases, none had progression of disease. CONCLUSIONS: Atypical mast cell infiltrates in the intestine are often subtle and can easily be overlooked. Clues to diagnosis include lamina propria expansion by monotonous cells with pale cytoplasm, admixed eosinophils, and the absence of crypt distortion or significant plasmacytic infiltrate. Although most patients with GI involvement by SM are symptomatic, a subset remain asymptomatic, and the absence of clinical suspicion of mast cell disease adds to the difficulty in making a diagnosis of SM.

Oesophageal intrasquamous IgG4 deposits: an adjunctive marker to distinguish eosinophilic oesophagitis from reflux oesophagitis.

AIMS: To explore the utility of an IgG4 immunohistochemical stain to help distinguish eosinophilic oesophagitis from gastroesophageal reflux disease. METHODS AND RESULTS: We examined 21 cases of eosinophilic oesophagitis and 25 cases of gastroesophageal reflux disease. The diagnosis of eosinophilic oesophagitis was based on the presence of oesophageal dysfunction, >15 eosinophils per high-power field, and a lack of response to proton pump inhibitors. Gastroesophageal reflux disease showed intraepithelial eosinophils, but a clinical and/or histological response to proton pump inhibitor therapy. We also evaluated an additional cohort of 22 cases with intraepithelial eosinophils. Immunohistochemical staining for IgG4 was performed. Sixteen of 21 (76%) eosinophilic oesophagitis cases showed intrasquamous extracellular IgG4 deposits, whereas all 25 gastroesophageal reflux disease cases were negative. Mucosal IgG4-positive plasma cells were identified in eosinophilic oesophagitis and gastroesophageal reflux disease cases in 58% and 40% of cases, respectively. Eosinophilic oesophagitis patients receiving treatment were less likely to be positive for intraepithelial IgG4 deposits (88% versus 53%). In the validation cohort, the sensitivity and specificity for eosinophilic oesophagitis were 88% and 100%, respectively. CONCLUSIONS: The presence of intrasquamous IgG4 deposits is a useful adjunctive marker in the distinction between eosinophilic oesophagitis and gastroesophageal reflux disease.

Small-cell predominant extranodal NK/T cell lymphoma, nasal type: clinicopathological analysis of a series of cases diagnosed in a Western population.

AIMS: Extranodal NK/T cell lymphoma, nasal type (ENKTCL) is usually composed of medium- to large-sized lymphoid cells showing prominent angiotrophism and tumour cell necrosis. We report 13 cases composed predominantly of small lymphocytes diagnosed in the United States and Western Europe. METHODS AND RESULTS: Patients included seven females and six males aged 17-75 years. Ten presented with sinonasal and three with buccal disease. Nine had stage IE/IIE and four had stage IV disease. In five of seven patients with multiple biopsies at different time-intervals, the lymphoma was misinterpreted as representing chronic inflammation on an earlier biopsy. In all cases morphology showed a dense infiltrate of small lymphoid cells with minimal cytological atypia. Necrosis, angioinvasion and angiodestruction were each seen in 17%, 22% and 17% of biopsies. Median Ki67 was 5%. Four patients died of lymphoma 4-16 months after diagnosis, including three of four patients with stage IV disease; seven (54%) are alive with no evidence of disease at a median of 39 months; one patient with stage IV disease is alive at 10 months and one recurred at 17 months. CONCLUSIONS: In sinonasal biopsies with predominantly small lymphocytic infiltrates with admixed chronic inflammation, focal hypercellularity, focal surface ulceration or microscopic bone invasion by small lymphoid cells should alert pathologists to the possibility of small-cell predominant ENKTCL. Awareness of the full histological spectrum of ENKTCL, particularly in non-endemic areas, is important in avoiding a delay in diagnosis and ensuring timely initiation of therapy.

MicroRNA-15b regulates reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expression in human uterine leiomyoma.

BACKGROUND: Human uterine leiomyoma (fibroids; LYO) are the most common benign neoplasms in reproductive-aged women. Dysregulated extracellular matrix and irregular LYO reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expression are thought to be mediated by aberrant microRNA (miR) expression. The relationship of miR-15b and RECK expression in LYO has not been studied. METHODS: The expression levels of miR-15b and RECK were determined by quantitative RT-PCR, Western blot, and immunohistochemistry in cultures derived from commercial primary leiomyoma (cpLYO) and myometrial (cpMYO) cell lines and leiomyoma (pLYO) and myometrium (pMYO) tissue from surgical samples respectively. The relationship between miR-15b and RECK expression in cpLYO and pLYO (compared to their respective myometrial controls) was evaluated following transfection of cell cultures with either miR-15b mimic or inhibitor. RESULTS: Elevated levels of miR-15b were observed in cpLYO (2.82-fold; p = 0.04) and pLYO cell (1.30-fold; p = 0.0001) cultures respectively compared to corresponding MYO cell controls. Following transfection with miR-15b mimic, cpLYO cells (0.62-fold; p < 0.0001) and pLYO cells (0.68-fold; p < 0.0001) demonstrated reduced RECK protein expression. Following transfection with miR-15b inhibitor, cpLYO cells (1.20-fold; p < 0.0001) and pLYO cells (1.31-fold; p = 0.0007) demonstrated elevated RECK protein expression. RECK protein expression was reduced in pLYO tissues (0.73-fold; p < 0.0001) and pLYO (0.47-fold; p = 0.047) cells when compared to the corresponding MYO tissue controls. CONCLUSION: Our findings suggest that miR-15b negatively regulates RECK expression in LYO, and increased miR-15b and decreased RECK expression may contribute to the pathobiology of LYO. The functional significance of miR-15b and RECK expression warrants further investigation as potential therapeutic targets for the treatment of human LYO.

The immunophenotypic spectrum of primary mediastinal large B-cell lymphoma reveals prognostic biomarkers associated with outcome.

Primary mediastinal large B-cell lymphoma (PMBL) is a distinct subtype of diffuse large B-cell lymphoma (DLBCL) that shows overlap with classical Hodgkin lymphoma (CHL) and a favorable prognosis compared to mediastinal gray-zone lymphoma (MGZL). We performed immunohistochemistry on initial diagnostic specimens of 49 cases of uniformly treated PMBL to determine the frequency and clinical significance of expression of antigens commonly seen in CHL and MGZL, along with markers previously shown to be prognostic in DLBCL, not otherwise specified. The median age was 37 years with a female:male ratio of 2.3. After a median follow-up of 78 months, 24% of patients had relapsed or refractory disease and 22% had died; the 5-year PFS was 70%. Variable CD15 expression was seen in 31% of cases, but was not associated with adverse outcome. Hans cell-of-origin, proliferation index, and MYC/BCL2 coexpression were not associated with outcome, while low PDL1 (P = 0.011) and high MUM1 (P = 0.065) staining were each associated with shorter PFS. A biologic risk score (one point each for low PDL1 and high MUM1) stratified patients into three prognostic risk groups for PFS (P = 0.001) and OS (P = 0.032). On separate multivariate models, low PDL1 was independent of R-IPI risk group for PFS (HR 6.0, P = 0.023), as was a biologic risk score of 2 (HR 5.6, P = 0.011). Incorporation of the biologic risk score sub-stratified patients within R-IPI groups for both PFS (P < 0.001) and OS (P < 0.001). In summary, we characterize the immunophenotypic spectrum of PMBL and identify PDL1 and MUM1 as prognostic biomarkers for high-risk disease. Am. J. Hematol. 91:E436-E441, 2016. © 2016 Wiley Periodicals, Inc.

Genome-wide analysis of immune system genes by expressed sequence Tag profiling.

Profiling studies of mRNA and microRNA, particularly microarray-based studies, have been extensively used to create compendia of genes that are preferentially expressed in the immune system. In some instances, functional studies have been subsequently pursued. Recent efforts such as the Encyclopedia of DNA Elements have demonstrated the benefit of coupling RNA sequencing analysis with information from expressed sequence tags (ESTs) for transcriptomic analysis. However, the full characterization and identification of transcripts that function as modulators of human immune responses remains incomplete. In this study, we demonstrate that an integrated analysis of human ESTs provides a robust platform to identify the immune transcriptome. Beyond recovering a reference set of immune-enriched genes and providing large-scale cross-validation of previous microarray studies, we discovered hundreds of novel genes preferentially expressed in the immune system, including noncoding RNAs. As a result, we have established the Immunogene database, representing an integrated EST road map of gene expression in human immune cells, which can be used to further investigate the function of coding and noncoding genes in the immune system. Using this approach, we have uncovered a unique metabolic gene signature of human macrophages and identified PRDM15 as a novel overexpressed gene in human lymphomas. Thus, we demonstrate the utility of EST profiling as a basis for further deconstruction of physiologic and pathologic immune processes.

Adrenomedullin is a therapeutic target in colorectal cancer.

The KRAS oncogene influences angiogenesis, metastasis and chemoresistance in colorectal cancers (CRCs), and these processes are all enhanced in hypoxic conditions. To define functional activities of mutant KRAS in a hypoxic microenvironment, we first performed cDNA microarray experiments in isogenic DKs5 and DKO3 colon cancer cell lines that differ only by their expression of mutant KRAS (K-ras(D13)). Adrenomedullin (ADM) was identified as one of the most significantly upregulated genes in DKs5 cells that express the KRAS oncogene in hypoxia (3.2-fold, p = 1.47 × 10(-5)). Ectopic expression of mutant KRAS (K-ras(V12)) in Caco-2 cells (K-ras(WT)) induced ADM, whereas selective knockdown of mutant KRAS alleles (K-ras(D13) or K-ras(V12)) in HCT116, DLD1 and SW480 colon cancer cells suppressed the expression of ADM in hypoxia. Knockdown of ADM in colon tumor xenografts blocked angiogenesis and stimulated apoptosis, resulting in tumor suppression. Furthermore, ADM also regulated colon cancer cell invasion in vitro. Among 56 patients with CRC, significantly higher expression levels of ADM were observed in samples harboring a KRAS mutation. Collectively, ADM is a new target of oncogenic KRAS in the setting of hypoxia. This observation suggests that therapeutic targets may differ depending upon the specific tumor microenvironment.