[Intramural esophageal abscess as a complication of an eosinophilic esophagitis]. / Intramurale ösophageale Abszedierung als Komplikation einer eosinophilen Ösophagitis.

Eosinophilic esophagitis is an important differential diagnosis in the presence of dysphagia or bolus obstruction of the esophagus. Delayed diagnosis of eosinophilic esophagitis can lead to strictures of the esophagus.We report on a young patient who presented with initially unclear retrosternal symptoms to our department. The diagnosis of eosinophilic esophagitis, complicated by an intramural abscess of the esophagus, was established. After spontaneous drainage of the abscess, antibiotic therapy and subsequent remission induction of eosinophilic esophagitis with orodispersible budesonide resulted in a good therapeutic outcome.

The expression of hematopoietic progenitor cell antigen CD34 is regulated by DNA methylation in a site-dependent manner in gastrointestinal stromal tumours.

The anatomic site-dependent expression of hematopoietic progenitor cell antigen CD34 is a feature of gastrointestinal stromal tumours (GISTs). The basis for the differential CD34 expression is only incompletely understood. This study aimed at understanding the regulation of CD34 in GISTs and clarification of its site-dependent expression. Two sample sets of primary GISTs were interrogated including 52 fresh-frozen and 134 paraffin-embedded and formalin-fixed specimens. DNA methylation analysis was performed by HumanMethylation450 BeadChip array in three cell lines derived from gastric and intestinal GISTs, and differentially methylated CpG sites were established upstream of CD34. The methylation degree was further quantified by pyrosequencing, and inverse correlation with CD34 mRNA and protein abundance was revealed. The gene's expression could be activated upon induction of DNA hypomethylation with 5-aza-2'-deoxycytidine in GIST-T1 cells. In patient samples, a strong inverse correlation of DNA methylation degree with immunohistochemically evaluated CD34 expression was documented. Both CD34 expression and DNA methylation levels were specific to the tumours' anatomic location and mutation status. A constant decrease in methylation levels was observed ranging from almost 100% hypermethylation in intestinal GISTs from duodenum to hypomethylation in rectum. CD34 was heavily methylated in gastric PDGFRA-mutant GISTs in comparison to hypomethylated KIT-mutant counterparts. Next to CD34 hypermethylation, miR-665 was predicted and experimentally confirmed to target CD34 mRNA in GIST-T1 cells. Our results suggest that CD34 expression in GISTs may undergo a complex control by DNA methylation and miR-665. Differential methylation and expression of CD34 in GISTs along the gastrointestinal tract axis and in tumours that harbour different gain-of-function mutations suggest the origin from different cell populations in the gastrointestinal tract.

Epigenetic Regulation of CD133 in Gastrointestinal Stromal Tumors.

OBJECTIVES: This study ascertained the regulation of the stem cell marker CD133 and its potential applicability for prognostication of gastrointestinal stromal tumors (GISTs). METHODS: A total of 95 resected GISTs were included in the study. CD133 protein expression was assessed immunohistochemically on tissue microarrays. Methylation percentage was quantified by pyrosequencing. Gene expression in cell lines GIST48b and GIST882 upon treatment with DNA demethylation agent 5-aza-2'-deoxycytidine was analyzed by quantitative polymerase chain reaction. RESULTS: The expression of hypermethylated CD133 could be reactivated in the GIST cell line upon hypomethylation with the drug. Similarly, in patient material, CD133 methylation percentage correlated inversely with the protein expression and reflected tumor size with hypermethylation in small (<2 cm) tumors and virtually no methylation in large (>10 cm) GISTs. The gene's methylation percentage and expression level were clearly specific to anatomic sites and distinct driver mutations. KIT -mutant gastric GISTs exhibited significantly lower methylation degrees and concomitant high CD133 protein abundance compared with KIT -mutant GISTs from the small intestine. CD133 hypermethylation was documented in PDGFRA -mutant gastric GISTs along with low CD133 expression compared with KIT -mutant gastric GISTs. High CD133 expression was a prognosticator of shorter disease-free survival in all patients. In a subgroup of KIT -mutant gastric GISTs, low CD133 methylation degree was correlated with a shorter disease-free survival. CONCLUSIONS: Our results strongly suggest epigenetic regulation of CD133 expression by promoter methylation in GISTs. Pending further validation studies, high abundance of the protein can serve as a marker for malignant GISTs.

SMARCB1 (INI-1)-deficient Sinonasal Carcinoma: A Series of 39 Cases Expanding the Morphologic and Clinicopathologic Spectrum of a Recently Described Entity.

To more fully characterize the clinical and pathologic spectrum of a recently described tumor entity of the sinonasal tract characterized by loss of nuclear expression of SMARCB1 (INI1), we analyzed 39 SMARCB1-deficient sinonasal carcinomas collected from multiple medical centers. The tumors affected 23 males and 16 females with an age range of 19 to 89 years (median, 52). All patients presented with locally advanced disease (T3, n=5; T4, n=27) involving the sinuses (mainly ethmoid) with variable involvement of the nasal cavity. Thirty patients received surgery and/or radiochemotherapy with curative intent. At last follow-up, 56% of patients died of disease 0 to 102 months after diagnosis (median, 15), 2 were alive with disease, and 1 died of an unrelated cause. Only 9 patients (30%) were alive without disease at last follow-up (range, 11 to 115 mo; median, 26). The original diagnosis of retrospectively identified cases was most often sinonasal undifferentiated carcinoma (n=14) and nonkeratinizing/basaloid squamous cell carcinoma (n=5). Histologically, most tumors displayed either a predominantly basaloid (61%) or plasmacytoid/rhabdoid morphology (36%). The plasmacytoid/rhabdoid form consisted of sheets of tumor cells with abundant, eccentrically placed eosinophilic cytoplasm, whereas similar cells were typically rare and singly distributed in the basaloid variant. Glandular differentiation was seen in a few tumors. None of the cases showed squamous differentiation or surface dysplasia. By immunohistochemistry, the tumors were positive for pancytokeratin (97%), CK5 (64%), p63 (55%), and CK7 (48%); and they were negative for NUT (0%). Epstein-Barr virus and high-risk human papillomavirus was not detected by in situ hybridization. Immunohistochemical loss of SMARCB1 (INI1) expression was confirmed for all 39 tumors. Investigation of other proteins in the SWI/SNF complex revealed co-loss of SMARCA2 in 4 cases, but none were SMARCA4 deficient or ARID1A deficient. Of 27 tumors with SMARCB1 fluorescence in situ hybridization analysis, 14 showed homozygous (biallelic) deletions and 7 showed heterozygous (monoallelic) deletions. SMARCB1-deficient sinonasal carcinoma represents an emerging poorly differentiated/undifferentiated sinonasal carcinoma that (1) cannot be better classified as another specific tumor type, (2) has consistent histopathologic findings (albeit with some variability) with varying proportions of plasmacytoid/rhabdoid cells, and (3) demonstrates an aggressive clinical course. This entity should be considered in any difficult-to-classify sinonasal carcinoma, as correct diagnosis will be mandatory for optimizing therapy and for further delineation of this likely underdiagnosed disease.

Molecular analysis of BRAF V600E mutation in multiple nodules of pulmonary Langerhans cell histiocytosis.

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare, smoking-related histiocytic disorder with variable clinical symptoms. Like in other non-pulmonary Langerhans cell proliferations, PLCH has recently been shown to harbour BRAF V600E mutations in a significant subset of cases, thus challenging the concept of PLCH being a reactive disorder. Here, we analysed 38 formalin-fixed and paraffin-embedded PLCH nodules of nine patients for BRAF mutation using two different molecular methods. Using pyrosequencing and allele-specific quantitative PCR (AS-PCR), BRAF V600E mutations were found in 16/38 (42%) and 31/37 (84%) nodules, respectively. Analysing different nodules of the same patients with pyrosequencing 3/6 patients showed a concordant BRAF mutation status. When allele-specific quantitative PCR was used, condordant results were found in 5/6 patients. Our findings clearly indicate that (a) the sensitivity of the method used is crucial in analysing BRAF mutation status, (b) AS-PCR is more sensitive in detecting BRAF V600E mutations than pyrosequencing,

In-depth mutational analyses of colorectal neuroendocrine carcinomas with adenoma or adenocarcinoma components.

Neuroendocrine carcinomas (NECs) of the colorectum are rare but highly aggressive neoplasms. These tumors show some shared genetic alterations with colorectal adenocarcinomas, and most of them have adjacent glandular adenoma or adenocarcinoma components. However, genetic data on colorectal NECs still are sparse and insufficient for definite conclusions regarding their molecular origin. Based on morphological characterization, panel and whole-exome sequencing, we here present results from an in-depth analysis of a collection of 15 colorectal NECs with glandular components, 10 of which by definition were mixed adenoneuroendocrine carcinomas (MANECs). Among shared genetic alterations of both tumor components, we most frequently found TP53, KRAS and APC mutations that also had highest allele frequencies. Mutations exclusive to glandular or neuroendocrine components outnumbered shared mutations but occurred at lower allele frequencies. Our findings not only provide additional evidence for a common clonal origin of colorectal NECs and adjacent glandular tumor components, but strongly suggest their development through the classical adenoma-carcinoma sequence. Moreover, our data imply early separation of glandular and neuroendocrine components during malignant transformation with subsequent independent mutational evolution.

Recurrent Somatic PDGFRB Mutations in Sporadic Infantile/Solitary Adult Myofibromas But Not in Angioleiomyomas and Myopericytomas.

Infantile myofibroma (MF) is an uncommon benign myofibroblastic tumor of infancy and childhood. Solitary adult MF shares similar features with infantile MF. The lesions occur in 3 clinicopathologic settings: solitary, multicentric, and generalized and can be either sporadic or familial. Traditionally, infantile MF has been included in the spectrum of infantile hemangiopericytoma. The recent World Health Organization classification listed MF, angioleiomyoma, and myopericytoma under the general heading of perivascular tumors in the sense of a morphologic spectrum of perivascular myoid cell neoplasms. Although activating germline PDGFRB mutations have recently been linked to familial infantile MF, the molecular pathogenesis of sporadic infantile and adult solitary MF remained unclear. In this study, we analyzed 25 solitary MFs without evidence of familial disease (9 infantile and 16 adult MFs) to address the question whether somatic PDGFRB mutations might be responsible for the sporadic form of the disease. Given the presumed histogenetic link of MF to myopericytoma and angioleiomyoma, we additionally analyzed a control group of 6 myopericytomas and 9 angioleiomyomas for PDGFRB mutations. We detected PDGFRB mutations in 6/8 (75%) analyzable infantile and in 11/16 (69%) adult MFs but in none of the angioleiomyomas or myopericytomas. In 2 infantile MFs, additional sequencing of the germline confirmed the somatic nature of PDGFRB mutations. To our knowledge, this is the first study reporting apparently somatic recurrent PDGFRB mutations as molecular driver events in the majority of sporadic infantile and adult solitary MFs. Our results suggest molecular distinctness of MF as compared with angioleiomyoma/myopericytoma. Investigation of more cases including those with atypical and worrisome features, as well as other mimickers in the heterogenous morphologic spectrum of MF, is mandatory for validating the potential diagnostic value of PDGFRB mutation testing as a possible surrogate in difficult-to-classify lesions.

Inactivating Mutations of RB1 and TP53 Correlate With Sarcomatous Histomorphology and Metastasis/Recurrence in Gastrointestinal Stromal Tumors.

OBJECTIVES: Loss-of-function mutations in TP53 and CDKN2A have been found at varying frequencies in gastrointestinal stromal tumors (GISTs), while no mutations of RB1 have been reported to date. The aim of the current study was to determine the mutation frequency of TP53, RB1, and CDKN2A in GISTs. METHODS: A cohort of 83 primary untreated GISTs was analyzed for mutations in TP53, RB1, and CDKN2A by massive parallel sequencing. Tumors with mutations in TP53 and RB1 were analyzed by fluorescence in situ hybridization for the corresponding gene loci. RESULTS: Two GISTs harbored inactivating mutations in RB1, and two other GISTs displayed inactivating mutations in TP53 All four tumors were KIT mutant high-risk tumors with highly cellular sarcomatous histomorphology and variable combinations of plump spindle cells to epithelioid highly atypical cells and high mitotic activity. Three of these patients developed recurrent or metastatic disease, while the fourth patient showed tumor rupture intraoperatively. The combined overall frequency of TP53 and RB1 mutations was 13% considering high-risk or malignant GISTs. CONCLUSIONS: TP53 and RB1 mutations seem to be restricted to high-risk/malignant GISTs and occur at an equal although relatively low frequency.

Combined DNA methylation and gene expression profiling in gastrointestinal stromal tumors reveals hypomethylation of SPP1 as an independent prognostic factor.

Gastrointestinal stromal tumors (GISTs) have distinct gene expression patterns according to localization, genotype and aggressiveness. DNA methylation at CpG dinucleotides is an important mechanism for regulation of gene expression. We performed targeted DNA methylation analysis of 1.505 CpG loci in 807 cancer-related genes in a cohort of 76 GISTs, combined with genome-wide mRNA expression analysis in 22 GISTs, to identify signatures associated with clinicopathological parameters and prognosis. Principal component analysis revealed distinct DNA methylation patterns associated with anatomical localization, genotype, mitotic counts and clinical follow-up. Methylation of a single CpG dinucleotide in the non-CpG island promoter of SPP1 was significantly correlated with shorter disease-free survival. Hypomethylation of this CpG was an independent prognostic parameter in a multivariate analysis compared to anatomical localization, genotype, tumor size and mitotic counts in a cohort of 141 GISTs with clinical follow-up. The epigenetic regulation of SPP1 was confirmed in vitro, and the functional impact of SPP1 protein on tumorigenesis-related signaling pathways was demonstrated. In summary, SPP1 promoter methylation is a novel and independent prognostic parameter in GISTs, and might be helpful in estimating the aggressiveness of GISTs from the intermediate-risk category.

Recurrent mutations within the amino-terminal region of ß-catenin are probable key molecular driver events in sinonasal hemangiopericytoma.

Sinonasal hemangiopericytoma (SN-HPC) is an uncommon, site-specific, low-grade mesenchymal neoplasm of probable perivascular myoid cell origin. In contrast to solitary fibrous tumors of soft tissue and sinonasal tract origin, SN-HPCs were recently shown to lack recurrent NAB2-STAT6 fusion variants. Other molecular alterations known to occur in some of soft tissue perivascular myoid cell neoplasms were also absent in SN-HPC; thus, the molecular pathogenesis of SN-HPCs remained unknown. Guided by whole-genome sequencing combined with RNA sequencing of an index case, we analyzed a total of six SN-HPCs for mutations within the amino-terminal region of the gene CTNNB1 (cadherin-associated protein), ß 1, 88 kDa, encoding ß-catenin. All six cases showed missense mutations, with amino acid substitutions clustering at positions 33 to 45, corresponding to the recognition site of the ß-catenin destruction complex. Similar CTNNB1 mutations have been described in a variety of epithelial and mesenchymal neoplasms. These mutations prevent ß-catenin phosphorylation and proteasomal degradation but promote its nuclear accumulation and subsequent increased transcription of Wingless-related integration site target genes. Consistent with these molecular findings, ß-catenin IHC showed consistent diffuse and strong nuclear staining of the tumor cells in all six SN-HPCs. Our results highlight, for the first time, CTNNB1 mutations as the likely initiating molecular events driving SN-HPC tumorigenesis, which places SN-HPC among the growing family of ß-catenin-driven mesenchymal neoplasms.

Pattern of TGFbeta receptor 1 expression differs between kras-mutated keratoacanthomas and squamous cell carcinomas of the skin.

PURPOSE: Increasing evidence indicates that TGFbeta- and EGFR-signaling is involved in the pathogenesis of keratoacanthoma (KA) and squamous cell carcinoma (SCC) of the skin. We analyzed the expression pattern of TGFbeta-signaling components and screened for mutations in tgfbetaR1, egfr, kras and braf in KAs and SCCs. METHODS: Immunohistochemical analysis of TGFbeta1, TGFbetaR1, TGFbetaR2 and phospho-SMAD2/3 was performed on skin tumors (29 KAs, 30 well and 31 moderately differentiated SCCs). Mutation screening in hotspot regions of tgfbetaR1, egfr, kras and braf was performed through pyrosequencing of tumor DNA. FINDINGS: Expression of TGFbeta1, TGFbetaR1 and p-SMAD2/3 was increased in tumors as compared to surrounding skin. In KAs characteristic strong discontinuous membranous TGFbetaR1 expression pattern frequently associated with kras mutation was noted. SCCs showed continuous TGFbetaR1 expression, stronger p-SMAD2/3 expression and less frequent kras mutations. In tumors at sun-exposed sites stronger TGFbetaR1 expression was noted. One SCC showed tgfbetaR1 mutation, but no other mutations were found. CONCLUSION: Although tgfbetaR1 germline mutations cause inherited KAs and our finding of strong discontinuous membranous expression in KAs suggests accumulation of functionally altered protein, we found no tgfbetaR1 mutations or influence on TGFbeta-signaling, but frequent kras mutations in this subgroup of KAs. Characteristic TGFbetaR1 expression pattern in KA can facilitate histopathologic distinction from SCC.

Phenotypical and molecular distinctness of sinonasal haemangiopericytoma compared to solitary fibrous tumour of the sinonasal tract.

AIMS: Sinonasal haemangiopericytoma (SN-HPC) is a rare sinonasal mesenchymal neoplasm of perivascular myoid cell origin. Solitary fibrous tumour (SFT) occurs only very rarely in the sinonasal tract. SFT and soft tissue HPC have been considered a single entity. Recently, recurrent gene fusions involving NAB2-STAT6 resulting in differential expression of STAT6 were characterized as central molecular events in SFT. However, no data exist for NAB2-STAT6 status or STAT6 expression in SN-HPC. METHODS AND RESULTS: We examined six SN-HPCs and two sinonasal SFTs by immunohistochemistry and RT-PCR for NAB2-STAT6 fusions. SN-HPC affected three females and three males (mean age: 72 years). They expressed smooth muscle actin, lacked strong CD34 reactivity and were negative for nuclear STAT6 expression. RT-PCR analysis confirmed the absence of NAB2-STAT6 fusions in all cases. Conversely, both sinonasal SFTs (in males aged 39 and 52 years) displayed classical features of pleuropulmonary and soft-tissue SFTs (uniformly CD34-positive with strong nuclear expression of STAT6). RT-PCR revealed NAB2-STAT6 fusions in both cases. CONCLUSIONS: These findings confirm the molecular and phenotypical distinctness of these two entities. While SN-HPC is a site-specific sinonasal neoplasm of as yet unknown molecular pathogenesis, sinonasal SFTs show phenotypical and molecular identity to their pleural/extrapleural counterparts.

Solitary fibrous tumors/hemangiopericytomas with different variants of the NAB2-STAT6 gene fusion are characterized by specific histomorphology and distinct clinicopathological features.

Recurrent somatic fusions of the two genes, NGFI-A-binding protein 2 (NAB2) and STAT6, located at chromosomal region 12q13, have been recently identified to be presumable tumor-initiating events in solitary fibrous tumors (SFT). Herein, we evaluated a cohort of 52 SFTs/hemangiopericytomas (HPCs) by whole-exome sequencing (one case) and multiplex RT-PCR (all 52 cases), and identified 12 different NAB2-STAT6 fusion variants in 48 cases (92%). All 52 cases showed strong and diffuse nuclear positivity for STAT6 by IHC. We categorized the fusion variants according to their potential functional effects within the predicted fusion protein and found strong correlations with relevant clinicopathological features. Tumors with the most common fusion variant, NAB2ex4-STAT6ex2/3, corresponded to classic pleuropulmonary SFTs with diffuse fibrosis and mostly benign behavior and occurred in older patients (median age, 69 years). In contrast, tumors with the second most common fusion variant, NAB2ex6-STAT6ex16/17, were found in much younger patients (median age, 47 years) and represented typical HPCs from deep soft tissue with a more aggressive phenotype and clinical behavior. In summary, these molecular genetic findings support the concept that classic pleuropulmonary SFT and deep-seated HPC are separate entities that share common features but correlate to different clinical outcome.

EGFR, KRAS, BRAF-mutations and microsatellite instability are absent in goblet cell carcinoids of the appendix.

Goblet cell carcinoid (GCC) is a rare type of mixed endocrine-exocrine tumor of the appendix often showing a clinically aggressive behavior. On a molecular basis, this tumor is only poorly understood. To analyze possible molecular similarities between GCC and colorectal cancer, we examined 14 cases of GCC for mutations in exons 18, 19 and 21 of the EGFR-gene, exon 2 in the KRAS gene and for V600E mutations of the BRAF gene. Although the sensitive pyrosequencing method was used, no EGFR, KRAS or BRAF mutations could be found. Furthermore, using immunohistochemistry, no evidence for microsatellite instabillity (MSI) could be found. Despite the partial intestinal differentiation of GCC, our study indicates that the molecular pathogenesis of GCC significantly differs from conventional colorectal adenocarcinoma. This finding might also have implications in adjuvant chemotherapeutic treatment of advanced GCC.

EGFR, HER2 and HER3 dimerization patterns guide targeted inhibition in two histotypes of esophageal cancer.

Receptor tyrosine kinases (RTKs) are in the focus of targeted therapy for epithelial tumors. Our study addressed the role of EGFR, HER2 and HER3 expression and dimerization in esophageal cancers in situ and in vitro in the context of therapeutic EGFR and HER2 inhibitors. In archival pretreatment biopsies of esophageal carcinomas (n = 110), EGFR was preferentially expressed in esophageal squamous cell carcinomas (ESCCs) (22.4%; p = 0.088) and HER2 (34.4%; p < 0.001) with HER3 (91.5%; p < 0.001) in esophageal (Barrett's) adenocarcinomas (EACs). In situ proximity ligation assays revealed mainly EGFR and HER2 homodimers in ESCC and EAC cases, respectively. However, EAC cases also exhibited HER2/HER3 heterodimers. In vitro ESCC (OE21) cells displayed a significant response to erlotinib, gefitinib and lapatinib, with loss of AKT phosphorylation, G0/G1 cell cycle arrest and induction of apoptosis. In EAC cells (OE19, OE33 and SK-GT-4), lapatinib was similarly effective in strongly HER2-positive (mainly HER2 homodimers and some HER2/EGFR heterodimers) OE19 and OE33 cells. The HER2-targeting antibodies (trastuzumab and pertuzumab) given alone were largely ineffective in ESCC and EAC cells. However, both antibodies significantly induced antibody-dependent cellular cytotoxicity in EAC (OE19 and OE33) cells upon co-culture with peripheral blood mononuclear cells. The study reveals that overexpression of EGFR and HER2 predominantly results in homodimers in ESCCs and EACs, respectively. Still, some EACs also show HER2 dimerization plasticity, e.g., with HER3. Such RTK dimerization patterns affect responses to EGFR and HER2 targeting inhibitors in ESCC and EAC cells in vitro and hence may influence future prediction for particularly HER2-targeting inhibitors in EACs.

Value of epithelioid morphology and PDGFRA immunostaining pattern for prediction of PDGFRA mutated genotype in gastrointestinal stromal tumors (GISTs).

AIMS: Genotyping is a prerequisite for tyrosine kinase inhibitor therapy in high risk and malignant GIST. About 10% of GISTs are wild-type for KIT but carry PDGFRA mutations. Applying the traditional approach, mutation analysis of these cases is associated with higher costs if all hotspots regions in KIT (exon 9, 11, 13, 17) are performed at first. Our aim was to evaluate the predictive value of a combined histomorphological-immunohistochemical pattern analysis of PDGFRA-mutated GISTs to efficiently direct KIT and PDGFRA mutation analysis. METHODS: The histomorphology and PDGFRA immunostaining pattern was studied in a test cohort of 26 PDGFRA mutants. This was then validated on a cohort of 94 surgically resected GISTs with mutations in KIT (n=72), PDGFRA (n=15) or with wild-type status (n=7) on a tissue microarray. The histological subtype (spindled, epithelioid, mixed), PDGFRA staining pattern (paranuclear dot-like/Golgi, cytoplasmic and/or membranous), and extent of staining were determined without knowledge of the genotype. The combination of histomorphology and immunophenotype were used to classify tumors either as PDGFRA- or non-PDGFRA phenotype. RESULTS: PDGFRA-mutated GISTs were significantly more often epithelioid (p<0.001) and had a higher PDGFRA expression, compared to KIT-mutants (p<0.001). Paranuclear PDGFRA immunostaining was almost exclusively observed in PDGFRA mutants (p<0.001). The sensitivity and specificity of this combined histological-immunohistochemical approach to predict the PDGFRA-genotype was 100% and 99%, respectively (p=6x10(-16)). CONCLUSION: A combination of histomorphology and PDGFRA immunostaining is a reliable predictor of PDGFRA genotype in GIST. This approach allows direct selection of the "gene/exons of relevance" to be analyzed and may help to reduce costs and work load and shorten processing time of GIST genotyping by mutation analysis.

High EpCAM expression is linked to proliferation and lauren classification in gastric cancer.

BACKGROUND: The association of EpCAM expression with the progression of gastric cancer remains unclear. Here, we investigated the expression of EpCAM in gastric cancer subtypes and correlated the data to tumor cell proliferation and clinicopathologic factors. METHODS: The intratumoral expression of EpCAM was assessed in 163 primary gastric cancers (61 diffuse-, 62 intestinal-, 32 mixed-type and 8 unclassified tumors) by immunohistochemistry, using the monoclonal antibody Ber-EP4. Intensity of staining was classified according the HercepTest-score using a standardized scoring system. Ki-67 was used to examine the proliferation in tumor tissue. RESULTS: Strong EpCAM expression was observed in 77% of the tumors and in 85% of the corresponding lymph nodes. Of the primary tumors, 58% (n=74) presented a homogeneous intratumoral EpCAM expression while 42% were characterised by a heterogenous expression pattern. Tumors with high EpCAM expression at the invasive front were associated with significantly (p=0.03) higher proportion of lymph node metastases and lower median overall survival (p=0.001). Diffuse type tumors presented a significantly higher EpCAM expression at the invasion front compared with the tumor centre (p=0.036). Multivariate survival analysis identified high EpCAM expression at the invasive front as an independent prognostic factor.We observed a significant (p=0.001) correlation between high EpCAM expression and higher tumor cell proliferation. CONCLUSION: High EpCAM expression associates with proliferation and progression of gastric cancer, especially in the diffuse type. Considering the discontenting results of the current adjuvant concepts for gastric cancer patients, EpCAM might be target in the adjuvant therapy of this malignant disease.

Training increases concordance in classifying pulmonary adenocarcinomas according to the novel IASLC/ATS/ERS classification.

The International Association for the Study of Lung Cancer (IASLC), the American Thoracic Society (ATS), and the European Respiratory Society (ERS) proposed a classification for lung adenocarcinomas (ADC) based on the predominant growth pattern. This classification has been shown to have prognostic and maybe even predictive impact. However, until now, the reproducibility of this classification has not been sufficiently demonstrated. Digital images of 40 selected ADC cases were shown twice to members of the Pulmonary Pathology Working Group of the German Society of Pathology. Each time a teledialogue-based survey on the classification was performed. Between the voting procedures, salient features of the novel classification were presented and discussed in detail by its members. The mean percentages of consensual votes per pattern ranged between 59.6 and 75 %, with lepidic and solid being the pattern with the most discordant and concordant votes, respectively. The other patterns ranged in between (papillary 65.8 %; acinar 67.8 %; micropapillary 74.2 %). The extent of disagreement decreased after the educational session. This decrease, however, was heterogeneous for the different patterns with acinar being the pattern with the strongest improvement. The overall number of abstentions decreased significantly after the educational session (p < 0.001) as well. The IASLC/ATS/ERS classification of lung ADC can be applied with reasonable consensus even for difficult cases in a nationwide context. The reproducibility evidently improves following educational sessions, even among experienced lung pathologists. Worldwide harmonization is clearly the next step on the way to a clinically meaningful, internationally accepted use of this novel prognostic and potentially predictive tool in lung pathology.

EBV-infection in cardiac and non-cardiac gastric adenocarcinomas is associated with promoter methylation of p16, p14 and APC, but not hMLH1.

BACKGROUND: Epstein-Barr virus (EBV)-associated gastric carcinomas (GC) constitute a distinct clinicopathological entity of gastric cancer. In order to determine underlying distinct aberrant promoter methylation we tested cardiac and non-cardiac GC with regard to the presence of EBV. METHODS: One hundred GC were tested by RNA- in situ hybridization for the presence of EBV by EBV-encoded small RNA (EBER). Aberrant promoter methylation was investigated by methylation-specific real-time PCR for p16, p14, APC and hMLH1. P16 protein expression was assessed by immunohistochemistry. RESULTS: In our selected study cohort, EBER-transcripts were detected in 19.6% (18/92) of GC. EBV-positive GC revealed significantly more often gene hypermethylation of p16, p14 and APC (p < 0.0001, p < 0.0001, and p = 0.02, respectively) than EBV-negative GC. The majority of GC with p16 hypermethylation showed a p16 protein loss (22/28). In contrast, no correlation between the presence of EBV and hMLH1 hypermethylation was found (p = 0.7). EBV-positive GC showed a trend towards non-cardiac location (p = 0.06) and lower stages (I/II) according to the WHO (p = 0.05). CONCLUSIONS: Hypermethylation of tumor suppressor genes is significantly more frequent in EBV-associated GC compared to EBV-negative GC. Our data add new insights to the role of EBV in gastric carcinogenesis and underline that EBV associated GC comprise a distinct molecular-pathologic as well as a distinct clinicopathological entity of GC.