Morphological, clinical and molecular characteristics in ARID1a­deficient microsatellite­stable oesophageal adenocarcinoma.

Publications describe the relevance of the AT-rich interactive domain-containing protein 1A (ARID1a) mutation in gastric adenocarcinoma, which occurs predominantly in the microsatellite instable (MSI)- and Epstein-Barr virus (EBV)-associated subtypes. It is unclear whether potential therapeutic, prognostic or morphologic descriptions are not epiphenomena of MSI (or EBV). Since personalised therapeutics are largely lacking for oesophageal adenocarcinoma (EAC), clinical trials investigating the efficacy of these therapeutics specifically in this subgroup are useful. To the best of our knowledge, this was the first study analysing the relevant tumour subset of microsatellite-stable (MSS) EAC with loss of function of ARID1a. A total of 875 patients with EAC and data from The Cancer Genome Atlas (TCGA) were analysed. Statistical analyses associating previously known molecular characteristics of the present tumour cohort, overall survival, morphological growth patterns and tumour heterogeneity issues were considered. Subsequently, 10% of EAC were ARID1a-deficient, the majority of which were MSS (7.5%). There was no characteristic growth pattern. Approximately 60% of tumours were PD-L1 positive to varying degrees. TP53 mutations occurred together with ARID1a defective EAC in the present cohort and in the TCGA collective. The extent of 7.5% MSS-EAC with ARID1a loss was unaffected by neoadjuvant therapy. ARID1a loss was often detected to be homogeneous (92%). ARID1a loss is not an epiphenomenon of MSI in EAC. The high homogeneity of ARID1a loss tumour clones could be considered an argument for the effectiveness of potential therapeutics. Since the majority of genomic ARID1a alterations result in protein loss, immunohistochemistry is a useful screening technique, especially in the absence of morphological characteristics.

FGFR2-amplified tumor clones are markedly heterogeneously distributed in carcinomas of the upper gastrointestinal tract.

BACKGROUND: FGFR2 is a therapy-relevant target in tumors of the upper gastrointestinal tract (GIT), and clinical trials are currently underway to test the efficacy of FGFR2 inhibitors. Tumor heterogeneity is one of the relevant causes of treatment failure. Almost nothing is known about the heterogeneous distribution of FGFR2-amplified clones in adenocarcinomas of the upper GIT. PATIENTS AND METHODS: To assess FGFR2 gene copy number alteration and intratumoral heterogeneity of upper GIT adenocarcinomas, we analyzed 893 patient-derived formalin-fixed paraffin-embedded tumor specimens, including primary operated and neoadjuvant-treated tumors (462 gastric carcinomas and 429 esophageal adenocarcinomas) as well as complementary lymph node and distant metastasis by fluorescence in situ hybridization. RESULTS: Twenty-six gastric tumors (5.6%) and 21 esophageal adenocarcinomas (4.9%) showed FGFR2 amplification. Overall, 93% of gastric carcinomas and 83% of esophageal carcinomas showed heterogeneous amplification. FGFR2 amplification was found in different histological growth patterns, including intestinal and diffuse type according to the Lauren classification. In the primary gastric carcinoma group, FGFR2 amplification was associated with poor prognosis (p = 0.005). CONCLUSION: Homogeneous FGFR2 amplification in tumors of the upper GIT is the exception. This has highly relevant implications in the nature of FGFR2 diagnostics (sufficient tumor cell number, determination of amplification at metastasis versus primary tumor, etc.) and on the response probability of appropriate inhibitors. It is relevant that the often poorly treatable and aggressive subtype of diffuse carcinomas (poorly cohesive carcinomas) also shows FGFR2 amplification and that an individualized therapy option with FGFR2 inhibitors could be an option in this group.

Occurrence of High Microsatellite-Instability/Mismatch Repair Deficiency in Nearly 2,000 Human Adenocarcinomas of the Gastrointestinal Tract, Pancreas, and Bile Ducts: A Study From a Large German Comprehensive Cancer Center.

INTRODUCTION: Knowledge of the high microsatellite-instability (MSI-H)/mismatch repair deficiency (MMRd) status is of increasing interest for personalized neoadjuvant or adjuvant therapy planning. Only a few studies are available on MSI-H distribution in the Northern European Caucasian patient population. In this study, we focused on a large cohort of tumors of the upper gastrointestinal tract. MATERIALS AND METHODS: Surgical material from a total of 1,965 patients was analyzed for MSI-H/MMRd status (including 1,267 carcinomas of the esophagus or stomach). All tumors were analyzed with an internationally recommended immunohistochemical panel consisting of four antibodies (MLH1, MSH2, PMS2, and MSH6). The results were molecularly objectified. RESULTS: Adenocarcinomas with MSI-H/MMRd were detected with the following distribution: esophagus (1.4%), stomach (8.3%), small intestine (18.2%), large intestine (8.5%), intrahepatic bile ducts (1.9%), and pancreas (0%). In case of gastric tumors with MSI-H/MMRd, neoadjuvant therapy did not influence the prognosis of patients (p = 0.94). Within all tumor entities with MSI-H/MMRd, patients with a UICC stage 4 were also represented. In this advanced stage, 11.7% of patients with MSS tumors were diagnosed compared to 0.5% of patients with MSI-H tumors relative to the entire tumor collective. DISCUSSION: In this study, the proportion of MSI-H/MMRd tumors in the stomach is smaller than would have been expected in knowledge of the data published by TCGA or AGRC. Negative prognostic effects regarding MSI-H status and neoadjuvant therapy as described by the MAGIC study group were not seen in our cohort. The extent to which the MSI-H/MMRd status should be known for neoadjuvant therapy planning must be clarified in prospective studies in the future. At present, there is no convincing data to dispense the neoadjuvant therapy for gastric carcinoma. Due to the very convincing, positive data regarding the response rates of MSI-H tumors to treatment with PD1/PD-L1 inhibitors, every metastatic carcinoma of the gastrointestinal tract should be tested for its MSI-H status.

Sex-specific prognostic effect of CD66b-positive tumor-infiltrating neutrophils (TANs) in gastric and esophageal adenocarcinoma.

BACKGROUND: Tumor-associated neutrophils (TANs) have recently been identified as a relevant component of the tumor microenvironment (TME) in solid tumors. Within the TME TANs mediate either tumor-promoting or tumor-inhibiting activities. So far, their prognostic relevance remains to be determined. This study aims to evaluate the prognostic relevance of TANs in different molecular subtypes of gastric and esophageal adenocarcinoma. METHODS: We analyzed a total of 1118 Caucasian patients divided into gastric adenocarcinoma (n = 458) and esophageal adenocarcinoma cohort (n = 660) of primarily resected and neoadjuvant-treated individuals. The amount of CD66b + TANs in the tumor stroma was determined using quantitative image analysis and correlated to both molecular, as well as clinical data. RESULTS: An accumulation of TANs in the tumor stroma of gastric carcinomas was associated to a significant favorable prognosis (p = 0.026). A subgroup analysis showed that this effect was primarily related to the molecular chromosomal instable subtype (CIN) of gastric carcinomas (p = 0.010). This was only observed in female patients (p = 0.014) but not in male patients (p = 0.315). The same sex-specific effect could be confirmed in adenocarcinomas of the esophagus (p = 0.027), as well as in female individuals after receiving neoadjuvant therapy (p = 0.034). CONCLUSIONS: Together, we show a sex-specific prognostic effect of TANs in gastric cancer within a Caucasian cohort. For the first time, we showed that this sex-specific prognostic effect of TANs can also be seen in esophageal cancer.

Amplification of KRAS and its heterogeneity in non-Asian gastric adenocarcinomas.

BACKGROUND: Gastric cancer is one of the deadliest cancer entities worldwide. While surgery is the only curative treatment option in early tumors, for locally advanced and metastatic patients further therapeutic targets are needed. Several studies not only reported mutations but also amplifications of the KRAS locus in different cancer entities. More recently, KRAS amplification was discussed as a new therapeutic target. Little is known about the (prognostic) relevance and (heterogenic) distribution of KRAS amplification in gastric adenocarcinomas, especially in Non-Asian patients. METHODS: Amplification of the KRAS locus and corresponding protein expression was analyzed in 582 gastric adenocarcinomas employing fluorescence in-situ hybridization (FISH) and immunohistochemistry. Amplification status was correlated with clinico-pathological features, clinical outcome and molecular tumor data including a correlation to the TCGA subtypes of gastric carcinoma. RESULTS: KRAS amplification was detected in 27 out of 470 analysable tumors (5.7%) and correlated with protein expression of KRAS in all amplified tumors. Within the KRAS amplified gastric tumors 14/27 (51.9%) showed a heterogeneous distribution with also KRAS non-amplified tumor parts. According to TCGA 24 tumors (88.8%) were related to chromosomal instable tumors (CIN). The survival analysis of the entire patient cohort did not show any difference in overall survival in dependence on the KRAS status. However, a significant survival difference with a worse outcome for patients with KRAS amplified tumors was identified when analysing patients without neoadjuvant pre-treatment. CONCLUSIONS: We confirm the unfavorable prognosis of KRAS amplified tumors reported by other studies in (Asian) patient groups, at least in patients without neoadjuvant pre-treatment. Within KRAS amplified tumors we revealed intratumoral heterogeneity that may define a (more aggressive) tumor cell population which is more frequently observed in patients with lymph node metastases. Despite the heterogeneous distribution of KRAS amplified tumor clones, KRAS amplified locally advanced or metastasized gastric adenocarcinomas represent a therapeutically highly relevant tumor subgroup.

The ambiguous role of microRNA-205 and its clinical potential in pancreatic ductal adenocarcinoma.

PURPOSE: Early treatment of pancreatic ductal adenocarcinoma (PDAC) is significantly delayed due to the lack of liquid biopsy markers for early diagnosis at surgically resectable tumor stages. Recent studies suggest that microRNA-205 (miR-205) is involved in PDAC progression by post-transcriptional regulation of epithelial-to-mesenchymal transition (EMT). However, the clinical potential of miR-205 as diagnostic and prognostic marker remains undefined and its exact role in PDAC is still ambiguous. This retrospective study is a substantial contribution to this on-going scientific discussion. METHODS: Expression analysis of miR-205 and its molecular targets in PDAC cell lines (n = 5), human tissue (n = 73), and blood serum samples (n = 85) by qRT-PCR, tissue microarray immunohistochemistry, and western blot. Descriptive and explorative statistical analysis of miR-205's clinical potential for diagnosis and prognosis of PDAC. RESULTS: The expression of miR-205 differs more than 2000-fold (p < 0.001) between epithelial and mesenchymal-like human PDAC cell lines correlating with EMT-marker expression of E-cadherin, vimentin, fibronectin, and ZEB-1. Expression of miR-205 is significantly upregulated in carcinoma tissue (eightfold, p = 0.028) and serum (2.3-fold, p = 0.023) of PDAC patients compared to age-matched healthy controls. In our patient collective circulating miR-205 in combination with CA.19-9 outperforms the diagnostic accuracy of CA.19-9 alone with an AUC of 0.890 (p < 0.001), sensitivity of 0.867, and specificity of 0.933. Though non-significant, low expression of circulating miR-205 is more frequent in advanced tumor stages combined with a worse overall survival (6.9 vs. 11.9 months, p = 0.176). CONCLUSION: Besides its controversial role in carcinogenesis, miR-205 shows high potential as a solid and liquid biopsy marker in PDAC. This result is an urgent call for larger confirmatory multi-center studies.

Clinical Impact of Epithelial-to-Mesenchymal Transition Regulating MicroRNAs in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive carcinoma entities worldwide with early and rapid dissemination. Recently, we discussed the role of microRNAs as epigenetic regulators of Epithelial-to-Mesenchymal Transition (EMT) in PDAC. In this study, we investigated their value as diagnostic and prognostic markers in tissue and blood samples of 185 patients including PDAC, non-malignant pancreatic disorders, and age-matched healthy controls. Expression of the microRNA-200-family (microRNAs -141, -200a, -200b, -200c, -429) and microRNA-148a was significantly downregulated in tissue of PDAC Union internationale contre le cancer (UICC) Stage II. Correspondingly, stromal PDAC tissue showed strong expression of Fibronectin, Vimentin, and ZEB-1 (Zinc finger E-box-binding homeobox) versus low expression of E-cadherin. Transient transfection of microRNA-200b and microRNA-200c mimics resulted in the downregulation of their key target ZEB-1. Inversely, blood serum analyses of patients with PDAC UICC Stages II, III, and IV showed a significant over-expression of microRNA-200-family members, microRNA-148a, microRNA-10b, and microRNA-34a. Correspondingly, Enzyme-linked Immunosorbent Assay (ELISA) analyses revealed a significant over-expression of soluble E-cadherin in serum samples of PDAC patients versus healthy controls. The best diagnostic accuracy to distinguish between PDAC and non-PDAC in this patient collective could be achieved in tissue by microRNA-148a with an area under the receiver-operating-characteristic (ROC) curve (AUC) of 0.885 and in blood serum by a panel of microRNA-141, -200b, -200c, and CA.19-9 with an AUC of 0.890. Both diagnostic tools outreach the diagnostic performance of the currently most common diagnostic biomarker CA.19-9 (AUC of 0.834). Kaplan Meier survival analysis of this patient collective revealed an improved overall survival in PDAC patients with high expression of tissue-related microRNA-34a, -141, -200b, -200c, and -429. In conclusion, EMT-regulating microRNAs have great potential as liquid and solid biopsy markers in PDAC patients. Their prognostic and therapeutic benefits remain important tasks for future studies.

Non-canonical WNT6/WNT10A signal factor expression in EBV+ post-transplant smooth muscle tumors.

Post-transplant smooth muscle tumors (PTSMTs) are rare mesenchymal neoplasms which occur after solid organ or haematopoietic stem cell transplantation. PTSMT typically consist of Epstein-Barr-virus (EBV)+ smooth muscle-like cells and show an intermediate malignancy. Their main occurrences are visceral organs, especially the liver, but intracranial appearances are described and associated with a poor prognosis. EBV drives the growth of PTSMT; however, the underlying molecular mechanisms still remain unclear. Gene expression analysis of a set of morphologically similar tumors (leiomyomas, leiomyosarcomas, angioleiomyomas and endothelial haemangiomas) from patients without immunosuppression or EBV-association was performed. Our findings indicate that PTSMT's growth is driven by two factors of the wingless-type protein family: WNT6 and WNT10A. We are first to report that in PTSMTs, a non-canonical activation of WNT, independent of beta-catenin, drives tumor cell proliferation via MTOR/AKT1, MYC and Cyclin D2.