The human tumor microbiome is composed of tumor type-specific intracellular bacteria.

Bacteria were first detected in human tumors more than 100 years ago, but the characterization of the tumor microbiome has remained challenging because of its low biomass. We undertook a comprehensive analysis of the tumor microbiome, studying 1526 tumors and their adjacent normal tissues across seven cancer types, including breast, lung, ovary, pancreas, melanoma, bone, and brain tumors. We found that each tumor type has a distinct microbiome composition and that breast cancer has a particularly rich and diverse microbiome. The intratumor bacteria are mostly intracellular and are present in both cancer and immune cells. We also noted correlations between intratumor bacteria or their predicted functions with tumor types and subtypes, patients' smoking status, and the response to immunotherapy.

Fecal microbiome signatures of pancreatic cancer patients.

Pancreatic cancer (PC) is a leading cause of cancer-related death in developed countries, and since most patients have incurable disease at the time of diagnosis, developing a screening method for early detection is of high priority. Due to its metabolic importance, alterations in pancreatic functions may affect the composition of the gut microbiota, potentially yielding biomarkers for PC. However, the usefulness of these biomarkers may be limited if they are specific for advanced stages of disease, which may involve comorbidities such as biliary obstruction or diabetes. In this study we analyzed the fecal microbiota of 30 patients with pancreatic adenocarcinoma, 6 patients with pre-cancerous lesions, 13 healthy subjects and 16 with non-alcoholic fatty liver disease, using amplicon sequencing of the bacterial 16S rRNA gene. Fourteen bacterial features discriminated between PC and controls, and several were shared with findings from a recent Chinese cohort. A Random Forest model based on the microbiota classified PC and control samples with an AUC of 82.5%. However, inter-subject variability was high, and only a small part of the PC-associated microbial signals were also observed in patients with pre-cancerous pancreatic lesions, implying that microbiome-based early detection of such lesions will be challenging.

Effect of N-Acetylserotonin on TLR-4 and MyD88 Expression during Intestinal Ischemia-Reperfusion in a Rat Model.

BACKGROUND: Accumulating evidence indicates that changes in intestinal toll-like receptors (TLRs) precede histological injury in a rodent model of necrotizing enterocolitis. N-acetylserotonin (NAS) is a naturally occurring chemical intermediate in the biosynthesis of melatonin. A recent study has shown that treatment with NAS prevents gut mucosal damage and inhibits programmed cell death following intestinal ischemia-reperfusion (IR). The objective of this study was to determine the effects of NAS on TLR-4, myeloid differentiation factor 88 (Myd88), and TNF-α receptor-associated factor 6 (TRAF6) expression in intestinal mucosa following intestinal IR in a rat. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomly assigned to one of the four experimental groups: 1) Sham rats underwent laparotomy; 2) Sham-NAS rats underwent laparotomy and were treated with intraperitoneal (IP) NAS (20 mg/kg); 3) IR rats underwent occlusion of both superior mesenteric artery and portal vein for 20 minutes followed by 48 hours of reperfusion; and 4) IR-NAS rats underwent IR and were treated with IP NAS immediately before abdominal closure. Intestinal structural changes, mucosal TLR-4, MyD88, and TRAF6 mucosal gene, and protein expression were examined using real-time PCR, Western blot, and immunohistochemistry. RESULTS: Significant mucosal damage in IR rats was accompanied by a significant upregulation of TLR-4, MyD88, and TRAF6 gene and protein expression in intestinal mucosa compared with control animals. The administration of NAS decreased the intestinal injury score, inhibited cell apoptosis, and significantly reduced the expression of TLR-4, MyD88, and TRAF6. CONCLUSION: Treatment with NAS is associated with downregulation of TLR-4, MyD88, and TRAF6 expression along with a concomitant decrease in intestinal mucosal injury caused by intestinal IR in a rat.

Surgical Biopsy of Pathologically Enlarged Lymph Nodes: A Reappraisal.

BACKGROUND: Enlarged lymph nodes (ELN) pose a great diagnostic challenge. They may represent the first clinical finding of a hematologic disease or other malignancy and may be an indication of a wide range of infectious and non-infectious diseases. Because many patients undergo percutaneous biopsy, surgical excisional biopsy is not often considered. OBJECTIVES: To analyze indications for a patient's referral for surgical biopsy of ELN and diagnostic steps to follow until referral, and to determine the number of ELN. METHODS: A retrospective study was conducted of prospectively collected data of patients who underwent surgical biopsy of ELN from January 2004 to December 2013. RESULTS: Of 118 patients who underwent surgical biopsy of ELN, only 52 (44%) had needle biopsy (NB) before referral. Lymphoma was diagnosed by NB in 24 (46%) of the referred patients. In patients with a previous diagnosis of lymphoma, NB of ELN yielded a sensitivity of 67% and specificity of 79%. In patients with lymphadenopathy but with no previous history of malignancy, sensitivity for lymphoma was 68% and specificity was 71%. The investigative time period until final diagnosis was 3 months in patients who had NB but only 1.25 months in patients who were referred directly for surgery (P < 0.0001). CONCLUSIONS: Surgical biopsy of ELN still has a place in the clinical evaluation of patients with ELN. Surgery may significantly reduce the length of investigation and prevent unnecessary diagnostics, especially in patients with suspected lymphoma recurrence.

The Effect of Elevated Intra-Abdominal Pressure on TLR4 Signaling in Intestinal Mucosa and on Intestinal Bacterial Translocation in a Rat.

BACKGROUND: Recent evidence suggests that elevated intra-abdominal pressure (IAP) may adversely affect the intestinal barrier function. Toll-like receptor 4 (TLR-4) is responsible for the recognition of bacterial endotoxin or lipopolysaccharide and for initiation of the Gram-negative septic shock syndrome. The objective of the current study was to determine the effects of elevated IAP on intestinal bacterial translocation (BT) and TLR-4 signaling in intestinal mucosa in a rat model. METHODS: Male Sprague-Dawley rats were randomly assigned to one of two experimental groups: sham animals (Sham) and IAP animals who were subjected to a 15 mmHg pressure pneumoperitoneum for 30 minutes. Rats were sacrificed 24 hours later. BT to mesenteric lymph nodes, liver, portal vein blood, and peripheral blood was determined at sacrifice. TLR4-related gene and protein expression (TLR-4; myeloid differentiation factor 88 [Myd88] and TNF-α receptor-associated factor 6 [TRAF6]) expression were determined using real-time PCR, western blotting, and immunohistochemistry. RESULTS: Thirty percent of sham rats developed BT in the mesenteric lymph nodes (level I) and 20% of control rats developed BT in the liver and portal vein (level II). abdominal compartment syndrome (ACS) rats demonstrated an 80% BT in the lymph nodes (Level I) and 40% BT in the liver and portal vein (Level II). Elevated BT was accompanied by a significant increase in TLR-4 immunostaining in jejunum (51%) and ileum (35.9%), and in a number of TRAF6-positive cells in jejunum (2.1%) and ileum (24.01%) compared to control animals. ACS rats demonstrated a significant increase in TLR4 and MYD88 protein levels compared to control animals. CONCLUSIONS: Twenty-four hours after the induction of elevated IAP in a rat model, increased BT rates were associated with increased TLR4 signaling in intestinal mucosa.

Wnt/ß-catenin signaling cascade down-regulation following massive small bowel resection in a rat.

BACKGROUND: Growing evidence suggests that the Wnt/ß-catenin signaling cascade is implicated in the control of stem cell activity, cell proliferation, lineage commitment, and cell survival during normal development and tissue regeneration of the gastrointestinal epithelium. The roles of this signaling cascade in stimulation of cell proliferation after massive small bowel resection are unknown. The purpose of this study was to evaluate the role of Wnt/ß-catenin signaling during late stages of intestinal adaptation in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into two groups: sham rats underwent bowel transection and SBS rats underwent a 75 % bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's digital gene expression analysis was used to determine Wnt/ß-catenin signaling gene expression profiling. Twelve Wnt/ß-catenin-related genes and ß-catenin protein expression were determined using real-time PCR, western blotting and immunohistochemistry. RESULTS: From the total number of 20,000 probes, 20 genes related to Wnt/ß-catenin signaling were investigated. From these genes, seven genes were found to be up-regulated and eight genes to be down-regulated in SBS vs. sham animals with a relative change in gene expression level of 20 % or more. From 12 genes determined by real-time PCR, nine genes were down-regulated in SBS rats compared to control animals including target gene c-Myc. SBS rats also showed a significant decrease in ß-catenin protein compared to control animals. CONCLUSION: Two weeks following massive bowel resection in rats, Wnt/ß-catenin signaling pathway is inhibited. In addition, it appears that cell differentiation rather than proliferation is most important in the late stages of intestinal adaptation.

Mixed neuroendocrine tumor of the common bile duct.

CONTEXT: Mixed adenoendocrine tumors of the extrahepatic bile ducts are exceedingly rare and most of those who are rarely diagnosed are adenocarcinomas. Neuroendorine tumors accounts for only 0.2-2%. CASE REPORT: We report a case of mixed adenoneuroendo-carcinoma of the common bile duct in an 82-year-old male. CONCLUSION: Clinical experience suggests that the neuroendocrine component of mixed tumors behave more aggressively than the regular biliary adenocarcinoma component. This clinical behavior may have an important role in the management of this clinical entity.

Abbreviated emergency laparotomy in the non-trauma setting.

BACKGROUND: Although the application of damage control surgery for trauma has been widely reported and defined, similar approach in non-trauma patients has not been well detailed. METHODS: A retrospective analysis of data from non-trauma patients who underwent emergency laparotomy between May 2006 and December 2008. Demographics, indications for surgery and outcome of patients who had definitive laparotomies (DL) and patients who had abbreviated laparotomies (AL) were compared. Appendectomies were excluded. RESULTS AND DISCUSSION: Two-hundred ninety-one patients (55% males) were included. Thirty-one (10.7%) underwent AL (58% males). Mean age of patients who had DL and AL was 65 and 62.8 years respectively. Peritonitis and mesenteric ischemia were more common indications in patients with AL than DL: 48.4% vs. 30.4% (p = 0.04) and 32.3% vs. 3.5% (p < 0.0001) respectively. Only 29% of patients who had AL were hemodynamically unstable. Mortality rates were 54.8% and 16.5% in patients with AL and DL respectively (p < 0.0001). Patients who died after AL and DL were significantly older than patients who survived (75 vs. 47.3 and 74 vs. 63 years respectively, p < 0.0001). Median hospital stay was 21 and 9 days for patients with AL and DL respectively (p < 0.05). Patients who underwent AL had significantly more wound infections, sepsis and multi-organ failure. CONCLUSION: The philosophy of damage control surgery is applied to non-trauma patients as some of the prerequisites for the decision to elect this strategy are the same. Peritonitis is the most common indication for AL in non-trauma patients.