Morphological subtypes of colorectal low-grade intraepithelial neoplasia: diagnostic reproducibility, frequency and clinical impact.

AIMS: Special histomorphological subtypes of colorectal low-grade intraepithelial neoplasia (LGIN) with variable prognostic impact were recently described in patients with inflammatory bowel disease (IBD) referred to as non-conventional dysplasia. However, they can also be found in patients without IBD. We aimed to analyse the reproducibility, frequency and prognostic impact of non-conventional colorectal LGIN in patients with and without IBD. METHODS: Six pathologists evaluated 500 specimens of five different LGIN-cohorts from patients with and without IBD. Non-conventional LGIN included hypermucinous, goblet cell-deficient, Paneth cell-rich and crypt cell dysplasia. A goblet cell-rich type and non-conventional LGIN, not otherwise specified were added. Results were compared with the original expert-consented diagnosis from archived pathology records. RESULTS: Four or more pathologists agreed in 86.0% of all cases. Non-conventional LGIN was seen in 44.4%, more frequently in patients with IBD (52%; non-IBD: 39.3%, p=0.005). In patients with IBD non-conventional LGIN associated with more frequent and earlier LGIN relapse (p=0.006, p=0.025), high-grade intraepithelial neoplasia (p=0.003), larger lesion size (p=0.001), non-polypoid lesions (p=0.019) and additional risk factors (p=0.034). Results were highly comparable with expert-consented diagnoses. In patients without IBD, non-conventional LGIN may indicate a higher risk for concurrent or subsequent colorectal carcinoma (CRC, p=0.056 and p=0.061, respectively). Frequencies and association with high-grade intraepithelial neoplasia or CRC varied between the different LGIN subtypes. CONCLUSIONS: Non-conventional histomorphology in colorectal LGIN is frequent and highly reproducible. Our results indicate an increased risk for CRC in patients with non-conventional LGIN, probably independent of IBD. We recommend reporting non-conventional LGIN in routine pathology reports.

MET Amplification in Non-Small Cell Lung Cancer (NSCLC)-A Consecutive Evaluation Using Next-Generation Sequencing (NGS) in a Real-World Setting.

In non-small cell lung cancer (NSCLC), approximately 1-3% of cases harbor an increased gene copy number (GCN) of the MET gene. This alteration can be due to de novo amplification of the MET gene or can represent a secondary resistance mechanism in response to targeted therapies. To date, the gold standard method to evaluate the GCN of MET is fluorescence in situ hybridization (FISH). However, next-generation sequencing (NGS) is becoming more relevant to optimize therapy by revealing the mutational profile of each NSCLC. Using evaluable n = 205 NSCLC cases of a consecutive cohort, this study addressed the question of whether an amplicon based NGS assay can completely replace the FISH method regarding the classification of MET GCN status. Out of the 205 evaluable cases, only n = 9 cases (43.7%) of n = 16 high-level MET amplified cases assessed by FISH were classified as amplified by NGS. Cases harboring a MET GCN > 10 showed the best concordance when comparing FISH versus NGS (80%). This study confirms that an amplicon-based NGS assessment of the MET GCN detects high-level MET amplified cases harboring a MET GCN > 10 but fails to detect the various facets of MET gene amplification in the context of a therapy-induced resistance mechanism.

[A rare case of renal ectopic thyroid tissue]. / Ein seltener Fall eines renalen ektopen Schilddrüsengewebes.

We present a rare case of ectopic thyroid tissue found during robotic nephrectomy of a kidney with a suspected malignant tumour. Such cases of ectopic thyroid tissue are extremely rare in the literature. If ectopic thyroid tissue occurs, it is usually found in the neck region or in the upper mediastinum. Clinical symptoms depend on size, localisation and hormonal function of the ectopic tissue. Surgical resection remains the treatment of choice; in individual cases, conservative treatment can be an option. This case report aims to emphasise that renal tumours of unknown origin might be paraneoplastic or ectopic tissue of other organs.

Sporadic adenoma or ulcerative colitis associated neoplasia? The endoscopist's information has an impact on diagnosis and patient management.

BACKGROUND: Diagnosing low grade intraepithelial neoplasia (LGIN) in patients with ulcerative colitis (UC) is difficult. Distinguishing between sporadic adenoma (SA) and UC associated LGIN is even more challenging but has clinical impact. We aimed to examine, if the morphological distinction between both entities is reliably possible, how it influences patient's outcome and the role of the endoscopist in this decision with respect to current endoscopy classification schemes. METHODS: Seven pathologists retrospectively reevaluated 425 cases of LGIN in UC patients, diagnosed between 2009 and 2017 with preceding expert consensus and follow up in two separate readings, based on published morphological differentiation criteria. In the first evaluation, the observers were blinded to any clinical data. In the second evaluation, they knew patients' age as well as endoscopic features. They also rated their subjective diagnostic certainty. RESULTS: Diagnostic correctness improved significantly in the second assessment as did the pathologists' confidence in their diagnoses (p < 0.001 - p = 0.019). Knowledge of clinical and endoscopical data led to a higher percentage of SA (71.8% vs. 85.6%). UC associated LGIN showed significant earlier LGIN relapse as well as more high grade intraepithelial neoplasia and carcinoma during follow up (p < 0.001, p < 0.001, p = 0.005). CONCLUSIONS: Distinction between SA and UC associated LGIN is important as it has an impact on patients' follow up and treatment. Morphological distinction remains difficult with moderate interobserver variability. Adequate clinical information significantly improves pathologists' diagnoses as well as their confidence in their diagnoses.

An international study comparing conventional versus mRNA level testing (TargetPrint) for ER, PR, and HER2 status of breast cancer.

To compare results from messenger RNA (mRNA)-based TargetPrint testing with those from immunohistochemistry (IHC) and in situ hybridization (ISH) conducted according to local standard procedures at hospitals worldwide. Tumor samples were prospectively obtained from 806 patients at 22 hospitals. The mRNA level of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was assessed by TargetPrint quantitative gene expression readouts. IHC/ISH assessments were performed according to local standards at the participating hospitals. TargetPrint readout showed a high concordance with IHC/ISH of 95 % (kappa 0.81) for ER, 81 % (kappa 0.56) for PR, and 94 % (kappa 0.76) for HER2. The positive/negative agreement between TargetPrint and IHC for ER, PR, and HER2 was 96 %/87 %, 84 %/74 %, and 74 %/98 %, respectively. The concordance rate in IHC/ISH results between hospitals varied: 88-100 % for ER (kappa 0.50-1.00); 50-100 % for PR (kappa 0.20-1.00); and 90-100 % for HER2 (kappa 0.59-1.00). mRNA readout of ER, PR, and HER2 status by TargetPrint was largely comparable to local IHC/ISH analysis. However, there was substantial discordance in IHC/ISH results between different hospitals. When results are discordant, the use of TargetPrint would improve the reliability of hormone receptor and HER2 results by prompting retesting in a reference laboratory.

Intraductal carcinoma of prostate reporting practice: a survey of expert European uropathologists.

BACKGROUND: It is unclear whether the reported variation in the diagnosis of intraductal carcinoma of the prostate (IDC-P) is due to variable interpretation of borderline morphology, use of different diagnostic criteria or both. AIMS: We sought to determine the degree of variation in the diagnostic criteria and reporting rules for IDC-P in prostate biopsies employed by expert uropathologists. METHODS: A questionnaire survey was circulated to 23 expert uropathologists from 11 European countries. RESULTS: Criteria used for diagnosis of IDC-P included solid intraductal growth (100%), dense cribriform (96%), loose cribriform/micropapillary with nuclear size >6× normal (83%) or comedonecrosis (74%) and dilated ducts >2× normal (39%). 'Nuclear size' was interpreted as nuclear area by 74% and nuclear diameter by 21%. Pure IDC-P in needle biopsies was reported by 100% and Gleason graded by 30%. All would perform immunohistochemistry in such cases to rule out invasive cancer. An IDC-P component associated with invasive cancer would be included in the determination of tumour extent and number of cores involved by 74% and 83%, respectively. 52% would include IDC-P component when grading invasive cancer. 48% would perform immunohistochemistry in solid or cribriform nests with comedonecrosis to exclude IDC-P (17% routinely, 30% if the focus appeared to have basal cells on H&E). 48% graded such foci as Gleason pattern 5 even if immunohistochemistry demonstrated the presence of basal cells. CONCLUSIONS: There is a need for more clarity in the definition of some of the diagnostic criteria for IDC-P as well as for greater standardisation of IDC-P reporting.

Molecular patterns in the evolution of serrated lesion of the colorectum.

Colorectal cancer (CRC) mostly develops from a variety of polyps following mainly three different molecular pathways: chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylation (CIMP). Polyps are classified histologically as conventional adenomas, hyperplastic polyps, sessile serrated adenomas/polyps (SSA/P) and traditional serrated adenomas (TSA). However, the association of these polyps with the different types of CRCs and the underlying genetic and epigenetic aberrations has yet to be resolved. In order to address this question we analyzed 140 tumors and 20 matched mucosae by array comparative genomic hybridization, by sequence analysis of the oncogenes BRAF, KRAS, PI3K3CA and by methylation arrays. MSI was tested indirectly by immunohistochemistry (IHC) and a loss of MLH1, MSH2, MSH6 or PMS2 was assigned as high microsatellite instability (MSI-H), while low microsatellite instability (MSI-L) was defined as MGMT IHC negativity only. CIN was detected in 78% of all MSI-H CRCs, most commonly as a gain of chromosome 8. Methylation data analyses allowed classification of samples into four groups and detected similar methylation profiles in SSA/P and MSI-H CRC. TSA also revealed aberrant methylation pattern, but clustered more heterogeneously and closer to microsatellite stable (MSS) CRCs. SSA/P, TSA and MSI-H CRCs had the highest degree of promotor methylation (CIMP pathway). Chromosomal instability, in contrast to the established doctrine, is a common phenomenon in MSI CRCs, yet to a lower extent and at later stages than in MSS CRCs. Methylation analyses suggest that SSA/P are precursors for MSI-H CRCs and follow the CIMP pathway.

Claudin-18 gene structure, regulation, and expression is evolutionary conserved in mammals.

Claudin-18 isoform 2 (CLDN18.2) is one of the few members of the human claudin family of tight junction molecules with strict restriction to one cell lineage. The objective of the current study was to compare molecular structure and tissue distribution of this gastrocyte specific molecule in mammals. We show here that the CLDN18.2 protein sequence is highly conserved, in particular with regard to functionally relevant domains in mouse, rat, rabbit, dog, monkey and human and also in lizards. Moreover, promoter regions of orthologs are highly homologous, including the binding site of the transcription factor cyclic AMP-responsive element binding protein (CREB), which is known to regulate activation of human CLDN18.2. Employing RT-PCR and immunohistochemistry, we found that, analogous to the human gene, all orthologous CLDN18.2 transcripts and proteins are exclusively expressed in differentiated gastric cells. Gene structure, promoter elements and RNA expression pattern of the lung-tissue specific Claudin-18 isoform 1 (CLDN18.1) as well, are homologous across species. These findings exemplify phylogenetic conservation of lineage-specific members of a multigene family. Given that CLDN18.2 is a novel drug target candidate, our data is also relevant for drug development as it reveals all six investigated mammalian species as suitable models for testing safety of CLDN18.2 targeting regimen.

Primary follicular lymphoma of the duodenum is a distinct mucosal/submucosal variant of follicular lymphoma: a retrospective study of 63 cases.

PURPOSE: Small series with limited follow-up have suggested primary follicular lymphoma of the duodenum (FL-D) to be an indolent disease. We report our experience on a large series of patients followed for a median time period of longer than 6 years. PATIENTS AND METHODS: The study comprised 63 patients with primary FL-D defined as stage I disease. Endoscopy and detailed pathologic work-up was performed at diagnosis and at restaging to monitor the behavior of the neoplastic process. RESULTS: Histologically, all 63 patients had FL, low grade (1 to 2). Duodenal endosonography demonstrated lesions confined to mucosa/submucosa in 19 of 20 patients. At an overall median follow-up of 77 months (range, 12 to 177 months), only two untreated patients had developed nodal disease, the remaining 61 patients never experienced extrasmall intestinal disease and large cell transformation did not occur at all. Among 24 patients followed by watch and wait strategy, seven showed spontaneous complete regression and 17 had stable disease; radiotherapy resulted in complete regression in all 19 patients; anti-CD20 antibody monotherapy achieved complete regression in four patients and stable disease in one patient. Various chemotherapy protocols in eight patients caused complete regression in all of them, but local relapses occurred in three. No patients required surgery or died of disease. CONCLUSION: These findings characterize primary FL-D as a remarkably indolent FL variant, which, even left untreated, does not develop tumorous growth, very rarely disseminates (two of 63 patients) and does not transform to high grade disease. A watch and wait approach appears to be the most sensible strategy.

ERG rearrangement in small cell prostatic and lung cancer.

AIMS: Small cell prostatic cancer is a rare but aggressive disease. Currently, its histogenetic origin is unclear and its distinction from metastatic small cell lung cancer is challenging. The aim of our study was to determine whether the ERG rearrangement commonly observed in acinar prostatic cancer can distinguish small cell prostatic cancer from small cell lung cancer samples. METHODS AND RESULTS: We assessed 15 small cell prostatic cancers and 22 small cell lung cancers for ERG rearrangement using fluorescence in situ hybridization. Commonly used and novel immunohistochemical markers (i.e. androgen receptor, calcium activated nucleotidase 1, Golgi phosphoprotein 2, prostate-specific antigen, prostate-specific membrane antigen, CD56, epithelial membrane antigen, thyroid transcription factor 1, chromogranin A, synaptophysin and Ki67) were further studied. ERG rearrangement occurred in 86% of small cell prostatic cancers but in none of the small cell lung cancers and was the best marker to differentiate between both tumours (P < 0.0001). CONCLUSIONS: The ERG rearrangement is commonly observed in small cell prostatic cancer, supporting the hypothesis that ERG rearrangement occurs in aggressive prostatic cancers. Furthermore, the ERG rearrangement is the most significant marker to differentiate between small cell prostatic cancer and small cell lung cancer. Moreover, our data suggest that small cell prostatic cancer is not a tumour entity on its own, but a dedifferentiated variant of common acinar prostatic cancer.

Selective activation of trophoblast-specific PLAC1 in breast cancer by CCAAT/enhancer-binding protein beta (C/EBPbeta) isoform 2.

The trophoblast-specific gene PLAC1 (placenta-specific 1) is ectopically expressed in a wide range of human malignancies, most frequently in breast cancer, and is essentially involved in cancer cell proliferation, migration, and invasion. Here we show that basal activity of the PLAC1 promoter is selectively controlled by ubiquitous transcription factor SP1 and isoform 2 of CCAAT/enhancer-binding protein beta that we found to be selectively expressed in placental tissue and cancer cells. Binding of both factors to their respective elements within the PLAC1 promoter was essential to attain full promoter activity. Estrogen receptor alpha (ERalpha) signaling further augmented transcription and translation of PLAC1 and most likely accounts for the positive correlation between PLAC1 expression levels and the ERalpha status we observed in primary breast cancer specimens. DNA affinity precipitation and chromatin immunoprecipitation assays revealed that transactivation of the PLAC1 promoter by ligand-activated ERalpha is based on a nonclassical pathway independent of estrogen-response elements, by tethering of ERalpha to DNA-bound CCAAT/enhancer-binding protein beta-2, and SP1. Our findings provide first insight into a novel and hitherto unknown regulatory mechanism governing selective activation of trophoblast-specific gene expression in breast cancer.

Budesonide is effective in treating lymphocytic colitis: a randomized double-blind placebo-controlled study.

BACKGROUND & AIMS: Budesonide is effective in treating collagenous colitis, but no treatment is established for lymphocytic colitis. We performed a randomized, double-blind, placebo-controlled study to evaluate the effects of budesonide in patients with lymphocytic colitis. METHODS: Forty-two patients (median age, 61 years) with lymphocytic colitis and chronic diarrhea were randomly assigned to groups that were given oral doses of budesonide (9 mg/d) or placebo for 6 weeks. Nonresponders at week 6 were given open-label budesonide (9 mg/d) for 6 additional weeks. A complete colonoscopy and histologic and quality-of-life analyses were performed at baseline and at week 6. The primary end point was clinical remission at 6 weeks, with last observation carried forward (LOCF). All patients who left the study in clinical remission were followed for relapse. RESULTS: At week 6, 86% of patients given budesonide were in clinical remission (with LOCF) compared with 48% of patients given placebo (P = .010). Furthermore, open-label budesonide therapy induced clinical remission in 7 of 8 patients given placebo. Histologic remission was observed in 73% of patients given budesonide compared with 31% given placebo (P = .030). Only 1 patient discontinued budesonide therapy prematurely. During a mean follow-up period of 14 months, 15 patients (44.1%) experienced a clinical relapse (after a mean of 2 months); 8 of the relapsing patients were retreated with and responded again to budesonide. CONCLUSIONS: Budesonide effectively induces clinical remission in patients with lymphocytic colitis and significantly improves histology results after 6 weeks. Clinical relapses occur but can be treated again with budesonide.

Claudin-18 splice variant 2 is a pan-cancer target suitable for therapeutic antibody development.

PURPOSE: Antibody-based cancer therapies have emerged as the most promising therapeutics in oncology. The purpose of this study was to discover novel targets for therapeutic antibodies in solid cancer. EXPERIMENTAL DESIGN: We combined data mining and wet-bench experiments to identify strictly gastrocyte lineage-specific cell surface molecules and to validate them as therapeutic antibody targets. RESULTS: We identified isoform 2 of the tight junction molecule claudin-18 (CLDN18.2) as a highly selective cell lineage marker. Its expression in normal tissues is strictly confined to differentiated epithelial cells of the gastric mucosa, but it is absent from the gastric stem cell zone. CLDN18.2 is retained on malignant transformation and is expressed in a significant proportion of primary gastric cancers and the metastases thereof. In addition to its orthotopic expression, we found frequent ectopic activation of CLDN18.2 in pancreatic, esophageal, ovarian, and lung tumors, correlating with distinct histologic subtypes. The activation of CLDN18.2 depends on the binding of the transcription factor cyclic AMP-responsive element binding protein to its unmethylated consensus site. Most importantly, we were able to raise monoclonal antibodies that bind to CLDN18.2 but not to its lung-specific splice variant and recognize the antigen on the surface of cancer cells. CONCLUSIONS: Its highly restricted expression pattern in normal tissues, its frequent ectopic activation in a diversity of human cancers, and the ability to specifically target this molecule at the cell surface of tumor cells qualify CLDN18.2 as a novel, highly attractive pan-cancer target for the antibody therapy of epithelial tumors.

Persistent diarrhea.

A 63-year-old man presented with massive diarrhea and weight loss. This was preceded by nonspecific symptoms for three years, which resembled sarcoidosis. By duodenal biopsy, the diagnosis of Whipples disease was confirmed. Antibiotic treatment resulted in rapid and complete disappearance of signs and symptoms.

In silico strategy for detection of target candidates for antibody therapy of solid tumors.

In contrast to earlier attempts for the identification of target candidates suitable for monoclonal antibody (mAb) based cancer therapies we concentrated on highly selective lineage-specific genes additionally preserved or even overexpressed in orthotopic cancers. In a script aided workflow we reduced all human entries of the RefSeq mRNA database to those encoding transmembrane domain bearing gene products and subjected them to BLAST analysis against the human EST database. All BLAST results were validated in a gene centric way allowing two types of data curation prior to expression profiling of matching ESTs in selected healthy tissues: (i) exclusion of questionable ESTs arising e.g. from genomic contamination and (ii) elimination of erroneously predicted mRNAs as well as transcripts with only weak EST coverage. The impact of such stringent input control on accuracy of prediction is underlined by RT-PCR confirmation of predicted tissue distribution patterns for a number of selected candidates.

A placenta-specific gene ectopically activated in many human cancers is essentially involved in malignant cell processes.

The identification and functional characterization of tumor-specific genes is a prerequisite for the development of targeted cancer therapies. Using an integrated data mining and experimental validation approach for the discovery of new targets for antibody therapy of cancer, we identified PLAC1. PLAC1 is a placenta-specific gene with no detectable expression in any other normal human tissue. However, it is frequently aberrantly activated and highly expressed in a variety of tumor types, in particular breast cancer. RNAi-mediated silencing of PLAC1 in MCF-7 and BT-549 breast cancer cells profoundly impairs motility, migration, and invasion and induces a G1-S cell cycle block with nearly complete abrogation of proliferation. Knockdown of PLAC1 is associated with decreased expression of cyclin D1 and reduced phosphorylation of AKT kinase. Moreover, PLAC1 is localized on the surface of cancer cells and is accessible for antibodies which antagonize biological functions of this molecule. These features, in summary, make PLAC1 an attractive candidate for targeted immunotherapeutic approaches.