Rupert Langer

Activation of Human Enteric Neurons by Supernatants of Colonic Biopsy Specimens From Patients With Irritable Bowel Syndrome

BACKGROUND & AIMS Pathological features in irritable bowel syndrome (IBS) include alterations in mucosal cell content and mediator release that might alter signaling to nearby submucosal neurons. METHODS Voltage sensitive dye imaging was used to record the effects of mediators, released from mucosal biopsies of IBS patients, on cell bodies of 1207 submucosal neurons from 76 human colonic tissue specimens. Supernatants, containing these mediators, were collected following incubation with colonic mucosal biopsies from 7 patients with diarrhea-predominant IBS (D-IBS), 4 with constipation-predominant IBS (C-IBS), and 4 healthy controls. Serotonin, histamine and tryptase concentrations in supernatants and lamina propria mast cell density were determined. RESULTS In contrast to controls, IBS supernatants significantly increased the rate of spike discharge in 58% of human submucosal neurons. Neurons that responded to IBS supernatant had a median spike frequency of 2.4 Hz compared to 0 Hz for control supernatants. Supernatants from C-IBS and D-IBS evoked similar spike discharge. The activation induced by IBS supernatants was inhibited by histamine receptor (H1-H3) antagonists, 5-HT3 receptor antagonist, and protease inhibition. Serotonin, histamine and tryptase levels in supernatants correlated with the spike discharge induced by the supernatants. Mast cells density as well as histamine and tryptase levels in supernatants were higher in IBS than in controls. CONCLUSIONS Mediators released from mucosal biopsies of IBS patients can activate human submucosal neurons. The activation required histamine, serotonin and proteases but was not associated with IBS subtype. Altered signaling between mucosa and the enteric nervous system might be involved in IBS pathogenesis.

Cetuximab plus cisplatin–5-fluorouracil versus cisplatin–5-fluorouracil alone in first-line metastatic squamous cell carcinoma of the esophagus: a randomized phase II study of the Arbeitsgemeinschaft Internistische Onkologie

BACKGROUND This study assessed the activity of the mAb cetuximab in combination with cisplatin and 5-fluorouracil (5-FU) in advanced esophageal squamous cell carcinoma. PATIENTS AND METHODS For a maximum of six 29-day cycles, patients received cisplatin 100 mg/m(2), day 1, plus 5-FU 1000 mg/m(2), days 1-5 (CF), either alone or in combination with cetuximab (CET-CF; 400 mg/m(2) initial dose followed by 250 mg/m(2) weekly thereafter). The primary end point was tumor response. Tumor material was obtained for analysis of KRAS mutation status. RESULTS Sixty-two eligible patients were included, 32 receiving CET-CF and 30 CF. Cetuximab did not exacerbate grade 3/4 toxicity, except for rash (6% versus 0%) and diarrhea (16% versus 0%). The overall response rate according to RECIST criteria was 19% and 13% and the disease control rate 75% and 57% for the CET-CF and CF arms, respectively. With a median follow-up of 21.5 months, the median progression-free survival was 5.9 and 3.6 months and median overall survival 9.5 and 5.5 months for CET-CF and CF, respectively. No KRAS codon 12/13 tumor mutations were identified in 37 evaluated samples. CONCLUSION Cetuximab can be safely combined with CF chemotherapy and may increase the efficacy of standard CF chemotherapy.

Loss of p53 in Enterocytes Generates an Inflammatory Microenvironment Enabling Invasion and Lymph Node Metastasis of Carcinogen-Induced Colorectal Tumors

Loss of p53 is considered to allow progression of colorectal tumors from the adenoma to the carcinoma stage. Using mice with an intestinal epithelial cell (IEC)-specific p53 deletion, we demonstrate that loss of p53 alone is insufficient to initiate intestinal tumorigenesis but markedly enhances carcinogen-induced tumor incidence and leads to invasive cancer and lymph node metastasis. Whereas p53 controls DNA damage and IEC survival during the initiation stage, loss of p53 during tumor progression is associated with increased intestinal permeability, causing formation of an NF-κB-dependent inflammatory microenvironment and the induction of epithelial-mesenchymal transition. Thus, we propose a p53-controlled tumor-suppressive function that is independent of its well-established role in cell-cycle regulation, apoptosis, and senescence.

Significance of histopathological tumor regression after neoadjuvant chemotherapy in gastric adenocarcinomas: a summary of 480 cases

Objective: An increasing number of patients with locally advanced gastric carcinomas (GC) are being treated with preoperative chemotherapy before surgery. Background: Histopathological tumor regression may have an important prognostic impact in addition to the UICC-TNM classification system. Methods: We evaluated the histopathological tumor regression in 480 surgical resection specimens of GC after neoadjuvant cisplatin-based chemotherapy, using an established system encompassing three tumor regression grades based on the estimation of the percentage of residual tumor tissue at the primary tumor site in relation to the macroscopically identifiable former tumor bed. Tumor regression was correlated to clinicopathological characteristics and patient survival. Results: Of the patients in this study, 102 (21.2%) had complete or subtotal tumor regression (<10% residual tumor), 121 (25.2%) had partial tumor regression (10–50% residual tumor), and 257 (53.5%) had minimal or no regression (>50% residual tumor). Tumor regression was significantly associated with posttreatment tumor category (pT), lymph node status (pN), lymphatic invasion status (pL), and resection status (P < 0.001). Major histopathological regression was less frequent in tumors of the distal stomach and tumors of nonintestinal type (P = 0.003). Tumor regression (P = 0.009) and postoperative Lymph node status (P < 0.001) were independent prognostic factors for survival in a multivariate analysis of tumor regression, ypT/N/L category, resection status, grading and Lauren´s classification. Conclusions: Assessment of histological tumor regression after preoperative chemotherapy in GC provides objective and highly valuable prognostic information in addition to posttherapeutic lymph node status. A standardized tumor regression grading system should be implemented in pathological reports of these tumors.

(18)F-FDG PET-guided salvage neoadjuvant radiochemotherapy of adenocarcinoma of the esophagogastric junction : the MUNICON II trial

Previous studies demonstrated that chemotherapy-induced changes in tumor glucose metabolism measured with 18F-FDG PET identify patients who benefit from preoperative chemotherapy and those who do not. The prognosis for chemotherapy metabolic nonresponders is poorer than for metabolic responders. Therefore, we initiated this prospective trial to improve the clinical outcome of metabolic nonresponders using a salvage neoadjuvant radiochemotherapy. Methods: Fifty-six patients with locally advanced adenocarcinomas of the esophagogastric junction were included. Tumor glucose uptake was assessed by 18F-FDG PET before chemotherapy and 14 d after initiation of chemotherapy. PET nonresponders received salvage neoadjuvant radiochemotherapy, whereas metabolic responders received neoadjuvant chemotherapy for 3 mo before surgery. Results: Thirty-three patients were metabolic responders, and 23 were nonresponders. Resection was performed on 54 patients. R0 resection rate was 82% (95% confidence interval [CI], 66%–91%) in metabolic responders and 70% (95% CI, 49%–84%) in metabolic nonresponders (P = 0.51). Major histologic remissions were observed in 12 metabolic responders (36%; 95% CI, 22%–53%) and 6 nonresponders (26%; 95% CI, 13%–46%). One-year progression-free rate was 74% ± 8% in PET responders and 57% ± 10% in metabolic nonresponders (log rank test, P = 0.035). One-year overall survival was comparable between the groups (∼80%), and 2-y overall survival was estimated to be 71% ± 8% in metabolic responders and 42% ± 11% in PET nonresponders (hazard ratio, 1.9; 95% CI, 0.87–4.24; P = 0.10). Conclusion: This prospective study showed the feasibility of a PET-guided treatment algorithm. However, by comparing the groups of nonresponding patients in the current trial and the previous published MUNICON (Metabolic response evalUatioN for Individualisation of neoadjuvant Chemotherapy in Esophageal and esophagogastric adeNocarcinoma) I trial, increased histopathologic response was observed after salvage radiochemotherapy, but the primary endpoint of the study to increase the R0 resection rate was not met. The prognosis of the subgroup of PET nonresponders remains poor, indicating their different tumor biology.

TFAP2E–DKK4 and Chemoresistance in Colorectal Cancer

BACKGROUND Chemotherapy for advanced colorectal cancer leads to improved survival; however, predictors of response to systemic treatment are not available. Genomic and epigenetic alterations of the gene encoding transcription factor AP-2 epsilon (TFAP2E) are common in human cancers. The gene encoding dickkopf homolog 4 protein (DKK4) is a potential downstream target of TFAP2E and has been implicated in chemotherapy resistance. We aimed to further evaluate the role of TFAP2E and DKK4 as predictors of the response of colorectal cancer to chemotherapy. METHODS We analyzed the expression, methylation, and function of TFAP2E in colorectal-cancer cell lines in vitro and in patients with colorectal cancer. We examined an initial cohort of 74 patients, followed by four cohorts of patients (total, 220) undergoing chemotherapy or chemoradiation. RESULTS TFAP2E was hypermethylated in 38 of 74 patients (51%) in the initial cohort. Hypermethylation was associated with decreased expression of TFAP2E in primary and metastatic colorectal-cancer specimens and cell lines. Colorectal-cancer cell lines overexpressing DKK4 showed increased chemoresistance to fluorouracil but not irinotecan or oxaliplatin. In the four other patient cohorts, TFAP2E hypermethylation was significantly associated with nonresponse to chemotherapy (P<0.001). Conversely, the probability of response among patients with hypomethylation was approximately six times that in the entire population (overall estimated risk ratio, 5.74; 95% confidence interval, 3.36 to 9.79). Epigenetic alterations of TFAP2E were independent of mutations in key regulatory cancer genes, microsatellite instability, and other genes that affect fluorouracil metabolism. CONCLUSIONS TFAP2E hypermethylation is associated with clinical nonresponsiveness to chemotherapy in colorectal cancer. Functional assays confirm that TFAP2E-dependent resistance is mediated through DKK4. In patients who have colorectal cancer with TFAP2E hypermethylation, targeting of DKK4 may be an option to overcome TFAP2E-mediated drug resistance. (Funded by Deutsche Forschungsgemeinschaft and others.).

Long-term outcome of 2920 patients with cancers of the esophagus and esophagogastric junction: evaluation of the New Union Internationale Contre le Cancer/American Joint Cancer Committee staging system.

Objective:We analyzed the long-term outcome of patients operated for esophageal cancer and evaluated the new seventh edition of the tumor-node-metastasis classification for cancers of the esophagus. Background:Retrospective analysis and new classification. Methods:Data of a single-center cohort of 2920 patients operated for cancers of the esophagus according to the seventh edition are presented. Statistical methods to evaluate survival and the prognostic performance of the staging systems included Kaplan-Meier analyses and time-dependent receiver-operating-characteristic-analysis. Results:Union Internationale Contre le Cancer stage, R-status, histologic tumor type and age were identified as independent prognostic factors for cancers of the esophagus. Grade and tumor site, additional parameters in the new American Joint Cancer Committee prognostic groupings, were not significantly correlated with survival. Esophageal adenocarcinoma showed a significantly better long-term prognosis after resection than squamous cell carcinoma (P < 0.0001). The new number-dependent N-classification proved superior to the former site-dependent classification with significantly decreasing prognosis with the increasing number of lymph node metastases (P < 0.001). The new subclassification of T1 tumors also revealed significant differences in prognosis between pT1a and pT1b patients (P < 0.001). However, the multiple new Union Internationale Contre le Cancer and American Joint Cancer Committee subgroupings did not prove distinctive for survival between stages IIA and IIB, between IIIA and IIIB, and between IIIC and IV. Conclusion:The new seventh edition of the tumor-node-metastasis classification improved the predictive ability for cancers of the esophagus; however, stage groups could be condensed to a clinically relevant number. Differences in patient characteristics, pathogenesis, and especially survival clearly identify adenocarcinomas and squamous cell carcinoma of the esophagus as 2 separate tumor entities requiring differentiated therapeutic concepts.

Coexpression of Cyclooxygenases (COX-1, COX-2) and Vascular Endothelial Growth Factors (VEGF-A, VEGF-C) in Esophageal Adenocarcinoma

Cyclooxygenases (COX), especially COX-2, are considered to be involved in carcinogenesis. Our study was initiated to test whether expression of COX isoforms (COX-1 and COX-2) is linked to expression of potent inducers of angiogenesis [vascular endothelial growth factor (VEGF)-A] and lymphangiogenesis (VEGF-C) in esophageal adenocarcinoma. One hundred twenty-three esophageal adenocarcinomas were investigated by means of quantitative reverse transcription-PCR for expression of COX-1, COX-2, VEGF-A, and VEGF-C. Additionally, COX-2 protein expression was determined using immunohistochemistry. Three esophageal cancer cell lines (OE-33, OSC-1, and OSC-2) were treated with COX-inhibiting substances (diclofenac, rofecoxib, and SC-560) and the effect on expression of the four genes was determined. COX-2 protein expression was found in all carcinomas under analysis. RNA expression levels of COX-1 and COX-2 varied markedly in carcinoma tissues and correlated significantly with each other (P < 0.001, r = 0.726). Furthermore, COX expression correlated with expression of VEGF-A (COX-1: P < 0.001, r = 0.753; COX-2: P < 0.001, r = 0.764) and VEGF-C (COX-1: P < 0.001, r = 0.778; COX-2: P < 0.001; r = 0.613). Exposure of esophageal cancer cell lines OE-33, OSC-1, and OSC-2 with three COX-inhibiting substances (diclofenac, rofecoxib, and SC-560) resulted in significantly reduced expression of VEGF-A and VEGF-C. In conclusion, our data suggest that both COX isoforms may be involved in the pathogenesis of esophageal adenocarcinoma, as they are linked to the expression of important modulators of angiogenesis (VEGF-A) and lymphangiogenesis (VEGF-C).

Tumor Classification of Six Common Cancer Types Based on Proteomic Profiling by MALDI Imaging

In clinical diagnostics, it is of outmost importance to correctly identify the source of a metastatic tumor, especially if no apparent primary tumor is present. Tissue-based proteomics might allow correct tumor classification. As a result, we performed MALDI imaging to generate proteomic signatures for different tumors. These signatures were used to classify common cancer types. At first, a cohort comprised of tissue samples from six adenocarcinoma entities located at different organ sites (esophagus, breast, colon, liver, stomach, thyroid gland, n = 171) was classified using two algorithms for a training and test set. For the test set, Support Vector Machine and Random Forest yielded overall accuracies of 82.74 and 81.18%, respectively. Then, colon cancer liver metastasis samples (n = 19) were introduced into the classification. The liver metastasis samples could be discriminated with high accuracy from primary tumors of colon cancer and hepatocellular carcinoma. Additionally, colon cancer liver metastasis samples could be successfully classified by using colon cancer primary tumor samples for the training of the classifier. These findings demonstrate that MALDI imaging-derived proteomic classifiers can discriminate between different tumor types at different organ sites and in the same site.

Prognostic significance of histopathological tumor regression after neoadjuvant chemotherapy in esophageal adenocarcinomas

We evaluated histomorphological findings in 92 surgical resection specimens of locally advanced esophageal adenocarcinomas after neoadjuvant cisplatin-based chemotherapy. Tumor response to neoadjuvant chemotherapy was determined using a system encompassing three tumor regression grades based on the estimation of the percentage of residual tumor tissue of the primary tumor site in relation to the macroscopically identifiable previous tumor bed. The significance of this system was validated by correlation of the tumor regression grades with the corresponding clinicopathological characteristics and patient survival. Seven patients (7%) had complete tumor regression (grade tumor regression grade 1), 48 patients (52%) had subtotal or partial tumor regression (tumor regression grade 2: 1–50% residual tumor), and 37 patients (40%) had minimal or no regression (tumor regression grade 3: >50% residual tumor). Tumor regression was significantly associated with posttreatment complete tumor resection status (UICC R0 status; P=0.016), tumor category (UICC pT category; P<0.001), and with the absence of either lymph node metastases (P=0.001) or lymphatic invasion (P<0.001). Survival analysis showed a significant prognostic relevance of the applied regression system in univariate (P<0.001) and multivariate analyses as a single independent factor (P=0.024). We conclude that the effect of preoperative chemotherapy in esophageal adenocarcinomas can be assessed by the determination of histological tumor regression, providing highly valuable prognostic information, which may even exceed the prognostic impact of the current TNM classification of these tumors. Therefore, we strongly recommend the implementation of a standardized tumor regression grading system in pathological reports of esophageal adenocarcinomas treated by neoadjuvant chemotherapy.