Peritoneal metastasis in gastric cancer: results from the German database.

BACKGROUND: Patients with peritoneal metastases of gastric cancer have a poor prognosis with a median survival of 7 months. A benefit of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) could be shown in several selected patient cohorts but remains controversial. The aim of this study was, to reflect the results of a national German HIPEC registry initiated by the German Society of General and Visceral Surgery (DGAV). METHODS: The DGAV HIPEC registry StuDoQ|Peritoneum documents patients with peritoneal malignancy contributed from 52 hospitals. All consecutive documented patients from 2011 until 2016 (n = 3078) were treated with CRS and HIPEC and were analysed. A total of 315 (10%) suffered from gastric cancer and were analysed. RESULTS: A complete data set of 235 patients was available for this study, including 113 male (48.1%) and 122 female (51.9%) patients with a median age of 53.4 years (SD ± 11.9). The median PCI was 8.0 (range 1-30). A complete cytoreduction was achieved in 121 patients (71.6%). Postoperative complications (Clavien-Dindo grades 3-4) occurred in 40 patients (17%). The median overall survival (OS) time was 13 months. The 5-year survival rate was 6%. According to the PCI from 0-6 (n = 74); 7-15 (n = 70) and 16-39 (n = 24) the median OS differs significantly (18 months vs. 12 months vs. 5 months; p = 0.002). CONCLUSIONS: CRS and HIPEC in selected patients with gastric cancer and peritoneal spread can improve survival when they are treated in centers. An accurate staging and patient selection are of major importance to achieve long-term survival.

Genome-wide association analysis of diverticular disease points towards neuromuscular, connective tissue and epithelial pathomechanisms.

OBJECTIVE: Diverticular disease is a common complex disorder characterised by mucosal outpouchings of the colonic wall that manifests through complications such as diverticulitis, perforation and bleeding. We report the to date largest genome-wide association study (GWAS) to identify genetic risk factors for diverticular disease. DESIGN: Discovery GWAS analysis was performed on UK Biobank imputed genotypes using 31 964 cases and 419 135 controls of European descent. Associations were replicated in a European sample of 3893 cases and 2829 diverticula-free controls and evaluated for risk contribution to diverticulitis and uncomplicated diverticulosis. Transcripts at top 20 replicating loci were analysed by real-time quatitative PCR in preparations of the mucosal, submucosal and muscular layer of colon. The localisation of expressed protein at selected loci was investigated by immunohistochemistry. RESULTS: We discovered 48 risk loci, of which 12 are novel, with genome-wide significance and consistent OR in the replication sample. Nominal replication (p<0.05) was observed for 27 loci, and additional 8 in meta-analysis with a population-based cohort. The most significant novel risk variant rs9960286 is located near CTAGE1 with a p value of 2.3×10-10 and 0.002 (ORallelic=1.14 (95% CI 1.05 to 1.24)) in the replication analysis. Four loci showed stronger effects for diverticulitis, PHGR1 (OR 1.32, 95% CI 1.12 to 1.56), FAM155A-2 (OR 1.21, 95% CI 1.04 to 1.42), CALCB (OR 1.17, 95% CI 1.03 to 1.33) and S100A10 (OR 1.17, 95% CI 1.03 to 1.33). CONCLUSION: In silico analyses point to diverticulosis primarily as a disorder of intestinal neuromuscular function and of impaired connective fibre support, while an additional diverticulitis risk might be conferred by epithelial dysfunction.

Detection of circulating tumor cells with CK20 RT-PCR is an independent negative prognostic marker in colon cancer patients - a prospective study.

BACKGROUND: Detection of circulating (CTC) or disseminated tumor cells (DTC) has been associated with negative prognosis and outcome in patients with colorectal cancer, though testing for these cells is not yet part of clinical routine. There are several different methodological approaches to detect tumor cells but standardized detection assays are not implemented so far. METHODS: In this prospective monocentric study 299 patients with colon cancer were included. CTC and DTC were detected using CK20 RT-PCR as well as immunocytochemistry staining with anti-pan-keratin and anti-EpCAM antibodies. The primary endpoints were: Evaluation of CTC and DTC at the time of surgery and correlation with main tumor characteristics and overall (OS) and disease free survival (DFS). RESULTS: Patients with detectable CTC had a 5-year OS rate of 68% compared to a 5-year OS rate of 85% in patients without detectable CTC in the blood (p = 0.002). Detection of DTC in the bone marrow with CK20 RT-PCR was not associated with a worse OS or DFS. Detection of pan-cytokeratin positive DTC in the bone marrow correlated with a significantly reduced 5-year OS rate (p = 0.048), but detection of DTC in the bone marrow with the anti-EpCAM antibody did not significantly influence the 5-year OS rate (p = 0.958). By multivariate analyses only detection of CTC with CK20 RT-PCR in the blood was revealed to be an independent predictor of worse OS (HR1.94; 95% CI 1.0-3.7; p = 0.04) and DFS (HR 1.94; 95% CI 1.1-3.7; p = 0.044). CONCLUSIONS: Detection of CTC with CK20 RT-PCR is a highly specific and independent prognostic marker in colon cancer patients. Detection of DTC in the bone marrow with CK20 RT-PCR or immunohistochemistry with anti-EpCAM antibody is not associated with a negative prognostic influence.

Cytokeratin 20 positive circulating tumor cells are a marker for response after neoadjuvant chemoradiation but not for prognosis in patients with rectal cancer.

BACKGROUND: Several studies have shown, that circulating tumor cells (CTC) have a negative prognostic value in colorectal cancer patients. Aim of this study was to evaluate the role of CTC in specifically rectal cancer patients regarding the influence on overall survival and to elucidate the impact of CTC in predicting response after chemoradiation (RCTX). METHODS: In this prospective monocentric study 267 patients with rectal cancer were included. Patients with locally advanced tumors were treated with RCTX followed by surgery. The primary endpoints were: Evaluation of CTC at the time of surgery and correlation with main tumor characteristics, response to neoadjuvant RCTX and overall survival (OS). CTC were detected in the blood using CK20 RT-PCR. RESULTS: Sixty-three patients were treated with neoadjuvant RCTX. In 46.8% of the patients receiving neoadjuvant RCTX CTC were detected, which was significantly higher than in the group without RCTX (p=0.002). Histopathologic regression after RCTX was evident in 27.8% of the patients. In the subgroup of responders after RCTX we found CTC at a significantly lower rate than in non-responders (p=0.03). No significant association was found between CTC detection and tumor characteristics and OS. The OS was significantly improved for responders compared to non-responders (p=0.007). CONCLUSIONS: Responders after neoadjuvant RCTX had a lower incidence of CTC compared to non-responders, which might be a result of effective systemic and local treatment prior to surgery. Interestingly, detection of CTC did not correlate with tumor stage and OS, which is in contrast to previous reports of patients with colon cancer.

Profile of serum factors and disseminated tumor cells before and after radiofrequency ablation compared to resection of colorectal liver metastases - a pilot study.

BACKGROUND/AIM: The degree of systemic response after hepatic radiofrequency ablation (RFA) has not been well-compared to liver resection so far. This pilot study was designed to examine whether RFA, compared to liver resection, significantly varies concerning dissemination of circulating tumor cells and induction of different pro-inflammatory markers and liver-specific growth factors. PATIENTS AND METHODS: Patients with colorectal liver metastases were treated with RFA, a combination of RFA and resection or liver resection only. Blood samples of 18 patients were obtained at different time points and interleukin (IL)-6, hepatocyte growth factor (HGF) and 70-kD heat shock protein (HSP70) serum levels were determined by ELISA. Circulating tumor cells were detected with reverse transcription-polymerase chain reaction (RT-PCR) amplification of cytokeratin 20 (CK20) mRNA (CK20 RT-PCR). RESULTS: The detection of circulating tumor cells was not significantly different, but in two patients RFA induced tumor cell dissemination. Serum levels of IL-6 were strongly elevated after the operation without any significant differences between the treatment groups. The HGF ratio was significantly higher after RFA+resection compared to resection-alone and the HSP70 ratio also showed significantly higher values after RFA compared to resection alone. High postoperative IL-6 and HGF levels negatively influenced overall survival (OS) independently of the treatment group. CONCLUSION: This pilot study demonstrates that RFA might influence tumor cell dissemination. There exist detectable differences in serum factors between RFA and liver resection after the operation but this did not influence the overall survival of the patients. For all patients, high postoperative IL-6 and HGF levels are negative prognostic markers.

Genetic and functional identification of the likely causative variant for cholesterol gallstone disease at the ABCG5/8 lithogenic locus.

UNLABELLED: The sterolin locus (ABCG5/ABCG8) confers susceptibility for cholesterol gallstone disease in humans. Both the responsible variant and the molecular mechanism causing an increased incidence of gallstones in these patients have as yet not been identified. Genetic mapping utilized patient samples from Germany (2,808 cases, 2,089 controls), Chile (680 cases, 442 controls), Denmark (366 cases, 766 controls), India (247 cases, 224 controls), and China (280 cases, 244 controls). Analysis of allelic imbalance in complementary DNA (cDNA) samples from human liver (n = 22) was performed using pyrosequencing. Transiently transfected HEK293 cells were used for [(3) H]-cholesterol export assays, analysis of protein expression, and localization of allelic constructs. Through fine mapping in German and Chilean samples, an ∼250 kB disease-associated interval could be defined for this locus. Lack of allelic imbalance or allelic splicing of the ABCG5 and ABCG8 transcripts in human liver limited the search to coding single nucleotide polymorphisms. Subsequent mutation detection and genotyping yielded two disease-associated variants: ABCG5-R50C (P = 4.94 × 10(-9) ) and ABCG8-D19H (P = 1.74 × 10(-10) ) in high pairwise linkage disequilibrium (r(2) = 0.95). [(3) H]-cholesterol export assays of allelic constructs harboring these genetic candidate variants demonstrated increased transport activity (3.2-fold, P = 0.003) only for the ABCG8-19H variant, which was also superior in nested logistic regression models in German (P = 0.018), Chilean (P = 0.030), and Chinese (P = 0.040) patient samples. CONCLUSION: This variant thus provides a molecular basis for biliary cholesterol hypersecretion as the mechanism for cholesterol gallstone formation, thereby drawing a link between "postgenomic" and "pregenomic" pathophysiological knowledge about this common complex disorder. (HEPATOLOGY 2012).

Unexpected findings on laparoscopy for suspected acute appendicitis: a pro for laparoscopic appendectomy as the standard procedure for acute appendicitis.

PURPOSE: Evaluation of the feasibility, cost-effectiveness, time of surgery, morbidities, and other/additional findings during laparoscopy for suspected appendicitis. METHODS: Prospective evaluation of 148 laparoscopies for suspected acute appendicitis. RESULTS: Laparoscopic appendectomy was safe and cost-effective. No appendiceal stump leaks or wound infections occurred. Of the patients, 4.7% developed intra-abdominal abscesses. Mean time of all procedures was 47 min: 42 min for simple appendectomies (n = 126), 67 min for perforated appendicitis (n = 15), and 75 min for converted procedures (n = 7). Twenty-one of 148 (14.2%) patients had unexpected findings instead of appendicitis: inflamed epiploic appendices (three times), inflammatory disorders of intestine (five times), intestinal adhesions (two times), ovarian cysts (six times: one time with mesenteric lymphadenitis, one time ruptured), tubo-ovarian abscess (one time), tubal necrosis (one time), adnexitis with mesenteric lymphadenitis (one time), and acute cholecystitis (one time). These diagnoses might have been missed during conventional open appendectomy and were, if necessary, treated during laparoscopy. CONCLUSIONS: Laparoscopic appendectomy should be recommended as standard procedure for acute appendicitis.

Investigation of innate immunity genes CARD4, CARD8 and CARD15 as germline susceptibility factors for colorectal cancer.

BACKGROUND: Variation in genes involved in the innate immune response may play a role in the predisposition to colorectal cancer (CRC). Several polymorphisms of the CARD15 gene (caspase activating recruitment domain, member 15) have been reported to be associated with an increased susceptibility to Crohn disease. Since the CARD15 gene product and other CARD proteins function in innate immunity, we investigated the impact of germline variation at the CARD4, CARD8 and CARD15 loci on the risk for sporadic CRC, using a large patient sample from Northern Germany. METHODS: A total of 1044 patients who had been operated with sporadic colorectal carcinoma (median age at diagnosis: 59 years) were recruited and compared to 724 sex-matched, population-based control individuals (median age: 68 years). Genetic investigation was carried out following both a coding SNP and haplotype tagging approach. Subgroup analyses for N = 143 patients with early manifestation of CRC (

Investigation of the colorectal cancer susceptibility region on chromosome 8q24.21 in a large German case-control sample.

Human chromosome 8q24.21 has been implicated as a susceptibility region for colorectal cancer (CRC) as a result of genome-wide association and candidate gene studies. To assess the impact of molecular variants at 8q24.21 upon the CRC risk of German individuals and to refine the disease-associated region, a total of 2,713 patients with operated CRC (median age at diagnosis: 63 years) were compared with 2,718 sex-matched control individuals (median age at inclusion: 65 years). Information on microsatellite instability in tumors was available for 901 patients. Association analysis of SNPs rs10505477 and rs6983267 yielded allelic p-values of 1.42 x 10(-7) and 2.57 x 10(-7), respectively. For both polymorphisms, the odds ratio was estimated to be 1.50 (95% CI: 1.29-1.75) under a recessive disease model. The strongest candidate interval, outside of which significance dropped by more than 4 orders of magnitude, was delineated by SNPs rs10505477 and rs7014346 and comprised 17 kb. In a subgroup analysis, the disease association was found to be more pronounced in MSI-stable tumors (odds ratio: 1.71). Our study confirms the role of genetic variation at 8q24.21 as a risk factor for CRC and localizes the corresponding susceptibility gene to a 17 kb candidate region.

Meta-analysis of genome-wide association data identifies four new susceptibility loci for colorectal cancer.

Genome-wide association (GWA) studies have identified multiple loci at which common variants modestly influence the risk of developing colorectal cancer (CRC). To enhance power to identify additional loci with similar effect sizes, we conducted a meta-analysis of two GWA studies, comprising 13,315 individuals genotyped for 38,710 common tagging SNPs. We undertook replication testing in up to eight independent case-control series comprising 27,418 subjects. We identified four previously unreported CRC risk loci at 14q22.2 (rs4444235, BMP4; P = 8.1 x 10(-10)), 16q22.1 (rs9929218, CDH1; P = 1.2 x 10(-8)), 19q13.1 (rs10411210, RHPN2; P = 4.6 x 10(-9)) and 20p12.3 (rs961253; P = 2.0 x 10(-10)). These findings underscore the value of large sample series for discovery and follow-up of genetic variants contributing to the etiology of CRC.

Electrolytic ablation is as effective as radiofrequency ablation in the treatment of artificial liver metastases in a pig model.

BACKGROUND: The best treatment option for liver metastases is complete surgical resection. Unfortunately, at the time of diagnosis, not all patients are candidates for complete resection. Electrolytic therapy (ECT) is a novel non-thermal method of tissue destruction. We evaluated its safety and effectiveness in comparison with radiofrequency ablation (RFA). METHODS: Tumor mimics were created by injecting a gel into the pig liver. The volume of the lesions was measured by ultrasound before treatment. The tumor mimics were treated with either RFA or electrolytic ablation. 48 h after treatment the liver was fixed in formalin and subjected to histological examination. RESULTS: Histological investigation confirmed that all lesions were completely surrounded by necrosis after treatment with either ECT or RFA. Two different types of necrosis were identified. After RFA the cell membranes disappeared but the nuclei were still intact, whereas after ECT these structures were completely disrupted. After ECT the necrosis was often surrounded by infiltrating lymphocytes. This inflammatory reaction was not apparent after RFA. CONCLUSION: ECT produced predictable and reproducible necrosis in pig livers and was as effective as RFA at destroying a defined target lesion. A local inflammatory reaction after ECT may favour the development of a systemic immune response. Our results indicate that ECT is an alternative treatment option for irresectable liver metastases.

Genome-wide association scan identifies a colorectal cancer susceptibility locus on 11q23 and replicates risk loci at 8q24 and 18q21.

In a genome-wide association study to identify loci associated with colorectal cancer (CRC) risk, we genotyped 555,510 SNPs in 1,012 early-onset Scottish CRC cases and 1,012 controls (phase 1). In phase 2, we genotyped the 15,008 highest-ranked SNPs in 2,057 Scottish cases and 2,111 controls. We then genotyped the five highest-ranked SNPs from the joint phase 1 and 2 analysis in 14,500 cases and 13,294 controls from seven populations, and identified a previously unreported association, rs3802842 on 11q23 (OR = 1.1; P = 5.8 x 10(-10)), showing population differences in risk. We also replicated and fine-mapped associations at 8q24 (rs7014346; OR = 1.19; P = 8.6 x 10(-26)) and 18q21 (rs4939827; OR = 1.2; P = 7.8 x 10(-28)). Risk was greater for rectal than for colon cancer for rs3802842 (P < 0.008) and rs4939827 (P < 0.009). Carrying all six possible risk alleles yielded OR = 2.6 (95% CI = 1.75-3.89) for CRC. These findings extend our understanding of the role of common genetic variation in CRC etiology.

Dexamethasone reduces tumor recurrence and metastasis after pancreatic tumor resection in SCID mice.

BACKGROUND: Glucocorticoids are among the most potent anti-inflammatory agents that act by inhibiting the synthesis of almost all known cytokines and influencing multiple transduction pathways. Inflammation accompanies most solid cancers including pancreatic ductal adenocarcinoma (PDAC), one of the most fatal cancers with surgery being the only potential curative therapeutic. In the present work we investigated the influence of glucocorticoids on PDAC cells in vitro as well as in vivo in a pancreatic carcinoma resection mouse model. METHODS: The influence of dexamethasone (DEX), a synthetic glucocorticoid, on proliferation and IL8 secretion in pancreatic cells (BxPC3, Colo357, PancTuI) was analyzed by cell counting and ELISA. NFkappaB-activity of PancTuI cells treated with DEX was determined by electrophoretic mobility shift assay (EMSA). Furthermore, effects of DEX on the invasiveness were studied by a fibroblast-based invasion assay. In the mouse resection model subtotal pancreatectomy was performed after orthotopic inoculation of human PDAC cells. DEX was administered after resection as an adjuvant treatment regime and 4 weeks later, local recurrent tumor sizes as well as number of liver and spleen metastases were analyzed. RESULTS: In vitro, DEX did not have an anti-proliferative effect on PDAC cells, but strongly reduced the invasiveness well as the activation of NFkappaB. The secretion of IL-8 into the supernatant of the tumor cells correlated inversely with the reduced activation of NFkappaB. In vivo, we observed a significant reduction of the local recurrent tumor volume and the number of liver and spleen metastases. CONCLUSIONS: DEX has a profound influence on the malignant phenotype of PDAC tumor cells in vitro in terms of inhibition of invasiveness and pro-inflammatory signaling. This was approved in vivo by reduced metastasizing capacity and reduced size of local tumor recurrence. Therefore, DEX-treatment appears to be an interesting therapeutical option in an adjuvant setting after pancreatic cancer resection.

Anti-tumor necrosis factor therapy inhibits pancreatic tumor growth and metastasis.

Chronic inflammation has been implicated in the pathogenesis of many severe autoimmune disorders, as well as in diabetes, pulmonary diseases, and cancer. Inflammation accompanies most solid cancers including pancreatic ductal adenocarcinoma (PDAC), one of the most fatal cancers with surgery being the only curative therapeutic approach currently available. In the present work, we investigated the role of the major proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) in the malignancy of PDAC cells in vitro and in vivo. In vitro, TNFalpha strongly increased invasiveness of Colo357, BxPc3, and PancTuI cells and showed only moderate antiproliferative effect. TNFalpha treatment of mice bearing orthotopically growing PDAC tumors led to dramatically enhanced tumor growth and metastasis. Notably, we found that PDAC cells themselves secrete TNFalpha. Although inhibition of TNFalpha with infliximab or etanercept only marginally affected proliferation and invasiveness of PDAC cells in vitro, both reagents exerted strong antitumoral effects in vivo. In severe combined immunodeficient mice with orthotopically growing Colo357, BxPc3, or PancTuI tumors, human-specific anti-TNF antibody infliximab reduced tumor growth and metastasis by about 30% and 50%, respectively. Importantly, in a PDAC resection model performed with PancTuI cells, we found an even stronger therapeutic effect for both anti-TNF compounds. Infliximab and etanercept reduced the number of liver metastases by 69% and 42%, respectively, as well as volumes of recurrent tumors by 73% and 51%. Thus, tumor cell-derived TNFalpha plays a profound role in malignancy of PDAC, and inhibition of TNFalpha represents a promising therapeutic option particularly in adjuvant therapy after subtotal pancreatectomy.

Superiority of extended neoadjuvant chemotherapy with gemcitabine in pancreatic cancer: a comparative analysis in a clinically adapted orthotopic xenotransplantation model in SCID beige mice.

BACKGROUND: Intensive efforts are being made to develop new approaches for adjuvant or neoadjuvant treatment in pancreas carcinoma. Recently, we established an animal model simulating an adjuvant therapeutic treatment setting. In order to additionally mimic a neoadjuvant treatment regime, we further developed the preclinical testing system. METHODS: Subtotal pancreatectomy was performed in mice after orthotopic inoculation of human pancreatic cancer cells (PancTu1). Four different settings were investigated: control without chemotherapy, adjuvant, neoadjuvant and extended neoadjuvant treatment protocols employing gemcitabine. All animals were autopsied 28 days after tumor resection. RESULTS: 28 of 32 animals survived the treatment setting. The largest pancreatic tumor masses were seen in animals without any chemotherapy, and the different chemotherapy protocols resulted in a stepwise reduction of the tumor mass. The mean weight of locally recurrent tumors was 553.1 +/- 133.2 mg (control) and 44 +/- 21.8 mg (adjuvant treatment group). Animals in the neoadjuvant treatment group developed larger tumor masses (215 +/- 191.3 mg) but fewer organ metastases. An extended neoadjuvant treatment setting proved to be most effective, resulting in the smallest tumor masses (25.6 +/- 8.8 mg) and the fewest organ metastases. CONCLUSION: Murine orthotopic tumor resection is an excellent simulation of the clinical situation and therefore provides a relevant option for preclinical comparative testing of new therapeutic strategies. To our knowledge, this is the first model described, in which all different therapeutic regimes for pancreatic carcinoma were systematically compared with each other in a standardized manner. The extended neoadjuvant regime proved to be superior.

A genome-wide association scan identifies the hepatic cholesterol transporter ABCG8 as a susceptibility factor for human gallstone disease.

With an overall prevalence of 10-20%, gallstone disease (cholelithiasis) represents one of the most frequent and economically relevant health problems of industrialized countries. We performed an association scan of >500,000 SNPs in 280 individuals with gallstones and 360 controls. A follow-up study of the 235 most significant SNPs in 1,105 affected individuals and 873 controls replicated the disease association of SNP A-1791411 in ABCG8 (allelic P value P(CCA) = 4.1 x 10(-9)), which was subsequently attributed to coding variant rs11887534 (D19H). Additional replication was achieved in 728 German (P = 2.8 x 10(-7)) and 167 Chilean subjects (P = 0.02). The overall odds ratio for D19H carriership was 2.2 (95% confidence interval: 1.8-2.6, P = 1.4 x 10(-14)) in the full German sample. Association was stronger in subjects with cholesterol gallstones (odds ratio = 3.3), suggesting that His19 might be associated with a more efficient transport of cholesterol into the bile.

Genetic investigation of DNA-repair pathway genes PMS2, MLH1, MSH2, MSH6, MUTYH, OGG1 and MTH1 in sporadic colon cancer.

Mutations in DNA repair genes have previously been identified as causative factors for hereditary nonpolyposis colon cancer (HNPCC). Recent evidence also supports an association between DNA sequence variation in these genes and sporadic colorectal carcinoma (CRC). Genetic investigation of DNA repair genes PMS2, MLH1, MSH2, MSH6, MUTYH, OGG1 and MTH1, as possible susceptibility factors for sporadic CRC, was done using both a haplotype tagging and a candidate (i.e. coding) single nucleotide polymorphism (SNP) approach. Some 1,068 patients with operated CRC (median age at diagnosis: 59 years) were compared to 738 sex-matched control individuals (median age: 67 years). Haplotype tagging SNPs, previously reported risk variants and all known coding SNPs with a minor allele frequency >0.005 were genotyped in PMS2 (N = 10), MLH1 (N = 11), MSH2 (N = 18), MSH6 (N = 15), MUTYH (N = 7), OGG1 (N = 11) and MTH1 (N = 3). No evidence for an association between CRC and any of the 7 genes was detected, neither with the tagging or coding SNPs nor in a sliding window haplotype analysis (all nominal p-values >0.05). The previously reported risk variants D132H in MLH1 and R154H in OGG1 were not even observed in the German population. Genetic CRC risk factors so far identified in DNA repair genes seem to be rare and population-specific. Their association with the disease could not be replicated in German CRC samples. It remains to be elucidated by more systematic, large-scale experiments whether common variants in the same genes, but present across populations, represent risk factors for sporadic CRC.

Establishment of a novel orthotopic xenograft model of human gallbladder carcinoma.

OBJECTIVE: Gallbladder cancer is characterized by high morbidity and mortality. An appropriate human xenograft animal model could serve as a research tool to investigate new therapeutic strategies. SUMMARY BACKGROUND DATA: To date, the few reports describing a xenograft animal model showed significant limitations. We improved a murine orthotopic human xenotransplantation model by implanting human gallbladder carcinoma cells directly into the lumen of the gallbladder. METHODS: Mz-ChA-1 cells were orthotopically injected into the gallbladder of Severe Combined Immune Deficiency (SCID) beige mice inducing the growth of solid tumors. The natural course of the disease, tumor growth, and metastases were analyzed. The cytotoxic drug gemcitabine was tested in vitro and in vitro. RESULTS: All animals revealed solid tumors in the inoculated area with liver infiltration. The median tumor volume in the untreated group was significantly higher than in the gemcitabine-treated group. Immunohistochemical staining revealed expression of human cytokeratin 7 and cytokeratin 8. To analyze tumor cell proliferation, the tumors were stained for the antigen Ki-67, and labeling indices were calculated for both groups. Animals receiving gemcitabine treatment showed significantly lower mean labeling indices. In vitro investigation revealed a significant reduction of DNA synthesis. DNA fragmentation, as a measure of apoptosis, was elevated by roughly 20% within 24 h of treatment. With this, we successfully established an orthotopic xenotransplant animal model and investigated the in vitro and in vivo effects of gemcitabine in human xenografted Mz-ChA-1 gallbladder adenocarcinoma. CONCLUSION: This model resembles the clinical situation as closely as possible and offers a relevant option for the preclinical testing of new therapeutic strategies.