[The two-in-one hit model of the short-cut carcinogenesis of colorectal carcinomas in MLH1-associated Lynch syndrome]. / Das Two-in-one-hit-Modell der beschleunigten Genese von kolorektalen Karzinomen beim MLH1-assoziierten Lynch-Syndrom.

In a recently published study a new genetic hypothesis was established that explained the existence of CTNNB1 mutations in Lynch syndrome-associated colorectal carcinomas (MLH1-LS-CRC). This hypothesis states that a mitotic recombination on chromosome 3p simultaneously leads to inactivation of the mismatch repair gene MLH1 and to the activation of CTNNB1. This explains the increased frequency of CTNNB1 mutations in MLH1-LS-CRC compared with other colon carcinomas. To test this hypothesis, various experiments were carried out that show that the first phase of recombination occurs in non-cancerous tissues, which favours the development of CTNNB1 mutations. This mechanism could explain the rapid tumour progression in MLH1-LS-CRC. The results highlight the importance of mitotic recombination in carcinogenesis and provide an insight into the genetic basis of colorectal carcinoma in the context of Lynch syndrome.

[Therapy of tumor recurrences or secondary carcinomas in pretreated area is not compatible with the primary therapy in non-previously treated tissue - an overview]. / Die Therapie von Tumorrezidiven bzw. Zweitkarzinomen in vorbehandeltem Gebiet ist nicht mit der Primärtherapie in nicht-vorbehandeltem Gewebe gleichzusetzen ­ eine Übersicht.

There are different initial situations in the treatment of local or locoregional recurrences, secondary carcinomas or residual squamous cell carcinomas of the head and neck region after primary therapy. The majority of patients with locoregional recurrences have had prior treatment consisting of surgery and/or postoperative radiotherapy or radiochemotherapy or primary radiotherapy or radiochemotherapy. In any case, it is a matter of new tumor growth in a previously treated area, which must be taken into account for the therapy decision. The biological backgrounds are diverse and are described in more detail and clinically classified in the present work.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with peritoneal surface malignancies (PSM): a prospective single-center registry study.

PURPOSE: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new, palliative approach for patients with peritoneal surface malignancies (PSMs). Its main goals are to control symptoms and ascites. For this experimental procedure, treatment efficacy and patient safety need to be closely monitored. METHODS: We performed a prospective registry study for patients with PSMs. Cisplatin (C) (7.5 mg/m2 body surface) and doxorubicin (D) (1.5 mg/m2) were administered laparoscopically via PIPAC. RESULTS: Between November 2015 and June 2020, we recorded data from 108 patients and 230 scheduled procedures. Tumor burden, patient fitness, quality of life, operating time and in-hospital stay remained stable over consecutive procedures. We recorded 21 non-access situations and 14 intraoperative complications (11 intestinal injuries, and three aspirations while inducing anesthesia). Three or more previous abdominal surgeries or cytoreductive surgery (CRS) with intraperitoneal hyperthermic chemoperfusion (HIPEC) were risk factors for non-access and intestinal injuries (χ2, p ≤ 0.01). Five Grade IV and three Grade V postoperative complications according to the Clavien-Dindo Classification (CDC) occurred. Median overall survival was 264 days (interquartile range 108-586). Therapies were primarily discontinued because of death (34%), progressive (26%), or regressive (16%) disease. CONCLUSION: PIPAC is effective in stabilizing PSMs and retaining quality of life in selected patients. Earlier abdominal surgeries and CRS with HIPEC should be considered when determining the indication for PIPAC. Randomized controlled studies are needed to evaluate PIPAC's therapeutic benefits compared to systemic chemotherapy (sCHT) alone. TRIAL REGISTRATION: NCT03100708 (April 2017).

Mismatch repair deficiency, chemotherapy and survival for resectable gastric cancer: an observational study from the German staR cohort and a meta-analysis.

PURPOSE: In a post hoc analysis of the MAGIC trial, patients with curatively resected gastric cancer (GC) and mismatch repair (MMR) deficiency (MMRd) had better median overall survival (OS) when treated with surgery alone but worse median OS when treated with additional chemotherapy. Further data are required to corroborate these findings. METHODS: Between April 2013 and December 2018, 458 patients with curatively resected GC, including cancers of the esophagogastric junction Siewert type II and III, were identified in the German centers of the staR consortium. Tumor sections were assessed for expression of MLH1, MSH2, MSH6 and PMS2 by immunohistochemistry. The association between MMR status and survival was assessed. Similar studies published up to January 2021 were then identified in a MEDLINE search for a meta-analysis. RESULTS: MMR-status and survival data were available for 223 patients (median age 66 years, 62.8% male), 23 patients were MMRd (10.3%). After matching for baseline clinical characteristics, median OS was not reached in any subgroup. Compared to perioperative chemotherapy, patients receiving surgery alone with MMRd and MMRp had a HR of 0.67 (95% CI 0.13-3.37, P = 0.63) and 1.44 (95% CI 0.66-3.13, P = 0.36), respectively. The meta-analysis included pooled data from 385 patients. Compared to perioperative chemotherapy, patients receiving surgery alone with MMRd had an improved OS with a HR of 0.36 (95% CI 0.14-0.91, P = 0.03), whereas those with MMRp had a HR of 1.18 (95% CI 0.89-1.58, P = 0.26). CONCLUSION: Our data support a positive prognostic effect for MMRd in GC patients treated with surgery only and a differentially negative prognostic effect in patients treated with perioperative chemotherapy. MMR status determined by preoperative biopsies may be used as a predictive biomarker to select patients for perioperative chemotherapy in curatively resectable GC.

[Gastrointestinal tract diseases induced by medications]. / Erkrankungen des Gastrointestinaltrakts unter medikamentöser Immunmodulation.

Gastrointestinal symptoms are common side effects of medical drugs. They are usually mild but sometimes require diagnostic endoscopy and histologic evaluation. Due to the rapidly increasing number of drugs developed especially for cancer treatment, pathologists are faced with a spectrum of different drug-associated histologies in all segments of the gastrointestinal tract. Some medication-induced mucosal damage features may mimic classical pathologies of nondrug-associated diseases, while others result in novel phenotypes. The present article focusses on the histologic presentations of gastrointestinal diseases induced by medications that either compromise or induce immune response.

[Ichthyosis uteri (psoriasis uteri) : A very rare disorder]. / Ichthyosis uteri (Psoriasis uteri) : Ein äußerst seltener Befund.

In ichthyosis uteri, the entire endometrium is replaced by squamous, sometimes even keratotic epithelium. The etiology is discussed controversially and not fully understood. However, in most cases a chronic inflammatory stimulus is identified. An association with malignancy is possible. Therefore, adequate consecutive diagnostic procedures, as well as exact macro- and micromorphologic evaluation is mandatory. In this case report we describe this currently rare disorder and review the main literature on this topic.

[Grading of tumors in the tubular digestive tract : Esophagus, stomach, colon and rectum]. / Grading der Tumoren des tubulären Verdauungssystems : Ösophagus, Magen, Kolon und Rektum.

Grading of tumors located in the tubular digestive tract is an integral component of pathology assessment reports but is subordinate to the histological typing of tumors with respect to the prognostic significance. Tumor grading has not been shown to be an independent prognostic marker for most tumor entities in the gastrointestinal tract; however, it may be relevant for further routine treatment decision making in early Union Internationale Contre le Cancer (UICC) stage cancers in which the prognosis for patients is less dominated by advanced tumor spread. Owing to the more favorable prognosis of microsatellite instability in colorectal cancer, the World Health Organization (WHO) has recommended that poorly differentiated tumors should be tested and graded as low grade (G1/G2) when microsatellite instability is detected. This recommendation has been integrated into the German S3 guidelines for colorectal cancers. Accordingly, microsatellite instability testing for grading purposes should become routine practice.

Uncoupling of EGFR-RAS signaling and nuclear localization of YBX1 in colorectal cancer.

The transcription factor YBX1 can act as a mediator of signals transmitted via the EGFR-RAS-MAPK axis. YBX1 expression has been associated with tumor progression and prognosis in multiple types of cancer. Immunohistochemical studies have revealed dependency between YBX1 expression and individual EGFR family members. We analyzed YBX1 and EGFR family proteins in a colorectal cancer (CRC) cohort and provide functional analyses of YBX1 in the context of EGFR-RAS-MAPK signaling. Immunohistochemistry for YBX1 and EGFR family receptors with two antibodies for YBX1 and EGFR were performed and related to clinicopathological data. We employed Caco2 cells expressing an inducible KRASV12 gene to determine effects on localization and levels of YBX1. Mouse xenografts of Caco2-KRASV12 cells were used to determine YBX1 dynamics in a tissue context. The two different antibodies against YBX1 showed discordant immunohistochemical stainings in cell culture and clinical specimens. Expression of YBX1 and EGFR family members were not correlated in CRC. Analysis of Caco2 xenografts displayed again heterogeneity of YBX1 staining with both antibodies. Our results suggest that YBX1 is controlled via complex regulatory mechanisms involving tumor stroma interaction and signal transduction processes. Our study highlights that YBX1 antibodies have different specificities, advocating their use in a combined manner.

A 2015 update on predictive molecular pathology and its role in targeted cancer therapy: a review focussing on clinical relevance.

In April 2013 our group published a review on predictive molecular pathology in this journal. Although only 2 years have passed many new facts and stimulating developments have happened in diagnostic molecular pathology rendering it worthwhile to present an up-date on this topic. A major technical improvement is certainly given by the introduction of next-generation sequencing (NGS; amplicon, whole exome, whole genome) and its application to formalin-fixed paraffin-embedded (FFPE) tissue in routine diagnostics. Based on this 'revolution' the analyses of numerous genetic alterations in parallel has become a routine approach opening the chance to characterize patients' malignant tumors much more deeply without increasing turn-around time and costs. In the near future this will open new strategies to apply 'off-label' targeted therapies, e.g. for rare tumors, otherwise resistant tumors etc. The clinically relevant genetic aberrations described in this review include mutation analyses of RAS (KRAS and NRAS), BRAF and PI3K in colorectal cancer, KIT or PDGFR alpha as well as BRAF, NRAS and KIT in malignant melanoma. Moreover, we present several recent advances in the molecular characterization of malignant lymphoma. Beside the well-known mutations in NSCLC (EGFR, ALK) a number of chromosomal aberrations (KRAS, ROS1, MET) have become relevant. Only very recently has the clinical need for analysis of BRCA1/2 come up and proven as a true challenge for routine diagnostics because of the genes' special structure and hot-spot-free mutational distribution. The genetic alterations are discussed in connection with their increasingly important role in companion diagnostics to apply targeted drugs as efficient as possible. As another aspect of the increasing number of druggable mutations, we discuss the challenges personalized therapies pose for the design of clinical studies to prove optimal efficacy particularly with respect to combination therapies of multiple targeted drugs and conventional chemotherapy. Such combinations would lead to an extremely high complexity that would hardly be manageable by applying conventional study designs for approval, e.g. by the FDA or EMA. Up-coming challenges such as the application of methylation assays and proteomic analyses on FFPE tissue will also be discussed briefly to open the door towards the ultimate goal of reading a patients' tissue as 'deeply' as possible. Although it is yet to be shown, which levels of biological information are most informative for predictive pathology, an integrated molecular characterization of tumors will likely offer the most comprehensive view for individualized therapy approaches. To optimize cancer treatment we need to understand tumor biology in much more detail on morphological, genetic, proteomic as well as epigenetic grounds. Finally, the complex challenges on the level of drug design, molecular diagnostics, and clinical trials make necessary a close collaboration among academic institutions, regulatory authorities and pharmaceutical companies.

Human equilibrative nucleoside transporter 1 expression analysed by the clone SP 120 rabbit antibody is not predictive in patients with pancreatic cancer treated with adjuvant gemcitabine - Results from the CONKO-001 trial.

BACKGROUND: High expression of human equilibrative nucleoside transporter 1 (hENT1) is considered to predict survival in patients treated with adjuvant gemcitabine for pancreatic cancer. A standard evaluation system for immunohistochemical analysis (antibody, scoring system) has not yet been established. METHODS: CONKO-001, a prospective randomised phase III study investigated the role of adjuvant gemcitabine (gem) as compared to observation (obs). Tumour samples of 156 patients were analysed by immunohistochemistry with the rabbit monoclonal antibody SP120 (Ventana Medical Systems) for expression of hENT1. Kaplan-Meier analyses for median disease-free survival (DFS) and overall survival (OS) were performed in dependence of hENT1 expression measured analogously to Farrell et al. 2009 and Poplin et al. 2013. RESULTS: For the 88 gem and 68 obs patients, median DFS/OS was 12.9/22.7 months and 6.2/19.1 months. High hENT1 expression was not associated with improved median DFS (Farrell: no hENT1 22.2 months, low hENT1 13.7 months, high hENT1 12.1 months, p=0.248; Poplin: low hENT1 13.2 months versus high hENT1 11.5 months, p=0.5) or median OS (Farrell: no hENT1 21.7 months, low hENT1 24.7 months, high hENT1 19.5, p=0.571; Poplin: low hENT1 24.4 months versus high hENT1 19.7 months, p=0.92;) in the gem group or in the obs group (median DFS Farrell: no hENT1 5.1 months, low hENT1 6.2 months, high hENT1 7.5 months, p=0.375; Poplin: low hENT1 6.2 months versus high hENT1 5.9 months, p=0.83; median OS Farrell: no hENT1 20.2months, low hENT1 17.7 months, high HENT1 19.1 months, p=0.738; Poplin: low hENT1 17.7 months versus high hENT1 20.4 months, p=0.65) measured by the Farrell or Poplin Score. CONCLUSIONS: We cannot confirm a predictive role of hENT1 measured by the clone SP120 rabbit antibody in our study population. Reproducible standard procedures are urgently needed prior to the implementation or exclusion of hENT1 as a predictive biomarker in the treatment of pancreatic cancer. TRIAL REGISTRATION: ISRCTN34802808.

[Histological diagnosis and complications of celiac disease. Update according to the new S2k guidelines]. / Histologische Diagnostik und Komplikationen der Zöliakie. Aktualisierung entsprechend der neuen S2k-Leitlinie.

Celiac disease is a relatively common immunological systemic disease triggered by the protein gluten in genetically predisposed individuals. Classical symptoms like chronic diarrhea, steatorrhea, weight loss and growth retardation are nowadays relatively uncommon. Diagnostic workup includes serological tests for IgA antibodies against tissue transglutaminase 2 (anti-TG2-IgA) and total IgA and histology of duodenal biopsies. Histomorphological classification should be done according to the modified Marsh-Oberhuber classification. Diagnosis of celiac disease should be based on serological, clinical, and histological findings. The only treatment is a life-long gluten-free diet. Unchanged or recurrent symptoms under gluten-free diet may indicate refractory celiac disease. Enteropathy-associated T-cell lymphoma and adenocarcinomas of the small intestine are known complications of celiac disease.

Transgenic expression of oncogenic BRAF induces loss of stem cells in the mouse intestine, which is antagonized by ß-catenin activity.

Colon cancer cells frequently carry mutations that activate the ß-catenin and mitogen-activated protein kinase (MAPK) signaling cascades. Yet how oncogenic alterations interact to control cellular hierarchies during tumor initiation and progression is largely unknown. We found that oncogenic BRAF modulates gene expression associated with cell differentiation in colon cancer cells. We therefore engineered a mouse with an inducible oncogenic BRAF transgene, and analyzed BRAF effects on cellular hierarchies in the intestinal epithelium in vivo and in primary organotypic culture. We demonstrate that transgenic expression of oncogenic BRAF in the mouse strongly activated MAPK signal transduction, resulted in the rapid development of generalized serrated dysplasia, but unexpectedly also induced depletion of the intestinal stem cell (ISC) pool. Histological and gene expression analyses indicate that ISCs collectively converted to short-lived progenitor cells after BRAF activation. As Wnt/ß-catenin signals encourage ISC identity, we asked whether ß-catenin activity could counteract oncogenic BRAF. Indeed, we found that intestinal organoids could be partially protected from deleterious oncogenic BRAF effects by Wnt3a or by small-molecule inhibition of GSK3ß. Similarly, transgenic expression of stabilized ß-catenin in addition to oncogenic BRAF partially prevented loss of stem cells in the mouse intestine. We also used BRAF(V637E) knock-in mice to follow changes in the stem cell pool during serrated tumor progression and found ISC marker expression reduced in serrated hyperplasia forming after BRAF activation, but intensified in progressive dysplastic foci characterized by additional mutations that activate the Wnt/ß-catenin pathway. Our study suggests that oncogenic alterations activating the MAPK and Wnt/ß-catenin pathways must be consecutively and coordinately selected to assure stem cell maintenance during colon cancer initiation and progression. Notably, loss of stem cell identity upon induction of BRAF/MAPK activity may represent a novel fail-safe mechanism protecting intestinal tissue from oncogene activation.

Functional characterization of the tumor-suppressor MARCKS in colorectal cancer and its association with survival.

The myristoylated alanine-rich C-kinase substrate (MARCKS) acts as a tumor suppressor in a variety of human neoplasms. In colorectal cancers (CRCs), MARCKS has been shown to be a preferential target of mutational inactivation in tumors following the microsatellite instability (MSI-H) pathway but little is known about its impact on intestinal carcinogenesis. To investigate the relevance of MARCKS inactivation in more detail, we analyzed 926 MSI-typed CRCs for MARCKS expression by immunohistochemistry and studied the functional consequences of MARCKS depletion in colorectal cancer cell lines. We found that loss of MARCKS expression was not restricted to MSI-H cancers but also occurred in microsatellite stable (MSS) tumors, where it was associated with an adverse outcome regarding overall survival, cancer-specific and disease-free survival (P=0.002, P=0.0018, P=0.0001, respectively; univariate analysis). In MARCKS-positive MSS colon cancer cell lines (SW480 and SW707) small interfering RNA (siRNA)-mediated knockdown of MARCKS conferred resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. This was accompanied by the downregulation of the TRAIL receptors DR4 and DR5 at the cell surface and activation of AKT signaling. Inhibition of AKT signaling and transient overexpression of wild-type MARCKS, but not of MARCKS lacking the effector domain (ED), abolished the anti-apoptotic effect. In conclusion, our data show that inactivation of MARCKS is common in CRCs and is associated with adverse outcome in MSS cancers. The finding that MARCKS acts as a mediator of apoptosis in MSS CRC cells adds a novel tumor-suppressing function to the so far established roles of MARCKS in cell motility and proliferation and can explain the prognostic effect of MARCKS depletion in MSS CRC.

Frequency of therapy-relevant staging shifts in colorectal cancer through the introduction of pN1c in the 7th TNM edition.

BACKGROUND: pN1c is a novel N-category introduced for colorectal cancer (CRC) in current TNM (Tumour, Node, Metastasis) classification. It represents cancers displaying tumour deposits (TDs) in the fat but no involvement of lymph nodes. pN1c is integrated into the UICC (International Union Against Cancer) staging system and shifts previous stage II cancers (6th edition) to stage III. We investigated the frequency of upstaging and TD prognostic significance. METHODS: 414 CRCs, consecutively collected during a population-based epidemiological study, TNM classified and UICC staged according to the 6th TNM edition were reinvestigated for TD presence. The association with survival was investigated after a median follow-up time of 5years in multivariate analyses among nodal negative and positive cases. RESULTS: TDs were found in 103 (24.9%) cancers and were strongly associated with T-, N- and M-stages (p<0.0001, each). Upstaging of previous stage II cancers by the presence of TDs (pN1c) was found in six of 140 cases (4.3% of stage II, 1.4% of all tumours). For stage III CRC, strongly reduced overall, CRC-specific and recurrence-free survival were observed with the presence of TDs (hazard ratios (HR) 2.29, 95% confidence interval 1.27-4.10, HR 2.51, 1.27-4.98, and HR 2.43, 1.32-4.48, respectively). CONCLUSIONS: Upstaging of CRCs through the introduction of pN1c occurs in less than 5% of previous stage II and less than 2% of all cancers. Given the biologic relevance of TDs, integration into the UICC staging relevant N-category is justified. The high prognostic impact of TDs, however, is not reflected in nodal positive cancers in both the TNM and UICC staging systems.

SPARC expression in resected pancreatic cancer patients treated with gemcitabine: results from the CONKO-001 study.

BACKGROUND: Previous investigations in pancreatic cancer suggested a prognostic role for secreted protein acidic and rich in cysteine (SPARC) expression in the peritumoral stroma but not for cytoplasmic SPARC expression. The aim of this study was to evaluate the impact of SPARC expression in pancreatic cancer patients treated with gemcitabine compared with untreated patients. PATIENTS AND METHODS: CONKO-001 was a prospective randomized phase III study investigating the role of adjuvant gemcitabine when compared with observation. Tissue samples of 160 patients were available for SPARC immunohistochemistry on tissue microarrays to evaluate its impact on patient outcome. RESULTS: Strong stromal SPARC expression was associated with worse disease-free survival (DFS) and overall survival (OS) in the overall study population (DFS: P = 0.005, OS: P = 0.033). Its negative prognostic impact was restricted to patients treated with gemcitabine (DFS: P = 0.007, OS: P = 0.006). High cytoplasmic SPARC expression also was associated with worse patient outcome (DFS: P = 0.041, OS: P = 0.011). Again the effect was restricted to patients treated with gemcitabine (DFS: P = 0.002, OS: P = 0.003). In multivariable analysis, SPARC expression was independently predictive of patient outcome. CONCLUSIONS: Our data confirm the prognostic significance of SPARC expression after curatively intended resection. The negative prognostic impact was restricted to patients who received adjuvant treatment with gemcitabine, suggesting SPARC as a predictive marker for response to gemcitabine.