Epigenetic changes in carcinogenesis of gallbladder

Salmonella enterica subsp. enterica host-pathogen interactions and their implications in gallbladder cancer

BACKGROUND

Several studies have linked chronic typhoid infection with gallbladder carcinoma without completely understood mechanism. This study was performed in order to understand role of Salmonella in gallbladder cancer etiology.

METHODS

Known Salmonella host-pathogen interactions were screened from database in addition to known gallbladder carcinoma targets. Host-pathogen interaction map of S. enterica was prepared and screened for interactions with gallbladder carcinoma targets. Further functional overrepresentation analysis was performed to understand the role of human targets involved in Salmonella host-pathogen interactions in gallbladder carcinoma.

RESULTS

Salmonella interact with several human proteins involved in gallbladder carcinoma. MAPK and RAC1 are the most important human proteins based on node degree value among all GBC associated interactors identified in current data search. Functional over-representation analysis reveals that Salmonella can induce adenocarcinoma which constitutes 85% of gallbladder cancer.

CONCLUSION

Though, the role of MAPK/ERK and PI3K/AKT/mTOR pathway is already suggested for Salmonella mediated gallbladder cancer, but current data based approach indicate several new insight for exploration of the role of Salmonella in gallbladder cancer etiology. The results indicate about several other processes including CREB/SP-1 and BSG(CD147) signaling, that must be given consideration for understanding the role of Salmonella in gallbladder cancer.

Dickkopf Homolog 3 (DKK3) Acts as a Potential Tumor Suppressor in Gallbladder Cancer

Gallbladder cancer (GBC) is a common malignancy of biliary tract cancers and its incidence has been rising rapidly worldwide. The prognosis for this disease is dismal as most of the symptoms are non-specific leading to a definitive diagnosis only at a late stage. Loss of DKK3 gene is associated with a possible tumor suppressor role in human cancers. The role and regulation of DKK3 in GBC have not been studied. We found that DKK3 expression levels were low in GBC patients and cell lines. Treatment of GBC cell lines with demethylating agent 5-Aza- 2'-deoxycytidine enhances its expression, establishing impact of methylation on DKK3 expression. We observed low expression of DKK3 in gallbladder adenocarcinoma tumors and highly invasive GBC cell lines. We showed that overexpression of DKK3 can decrease cell invasion, proliferation, and colony forming ability of GBC cells. Our data thus demonstrated the DKK3 gene is a potential tumor suppressor gene in GBC and aberrant promoter methylation could be involved in its downregulation, which may play a role in the tumorigenesis and aggressiveness of GBC.

Palliation of malignant gastroduodenal obstruction with self-expandable metal stent using side- and forward-viewing endoscope: Feasibility and outcome

Background

The endoscopic placement of a self‐expandable metal stent (SEMS), an alternative to surgical bypass for the palliation of malignant gastric outlet obstruction (GOO), is commonly performed using a forward‐viewing endoscope with a wide therapeutic channel; however, due to limited availability, most Indian centers use a side‐viewing duodenoscope. We studied the feasibility and outcome of SEMS placement using side‐ and forward‐viewing endoscopes.

Method

Data of patients undergoing SEMS placement using side‐ and forward‐viewing endoscopes with a therapeutic channel for the palliation of malignant GOO presenting during a 5‐year period were analyzed retrospectively. Follow‐up data were obtained from records and telephonic interviews, and technical and clinical success, complications, and survival were evaluated.

Results

Of 114 patients (age 56.5 ± 11.6 years, 59 [52%] female), 90 (79%) and 24 (21%) underwent SEMS placement using side‐ and forward‐viewing endoscopes, respectively. Technical (89, 98.9% vs. 24, 100%, P = ns) and clinical success (84, 93.3% vs. 23, 95.8%, P = ns) and complication rate (3, 3.3% vs. 0, P = ns) between side‐ and forward‐viewing endoscopes were comparable. However, SEMS could be placed in a shorter time using a forward‐ rather than side‐viewing endoscope (21 min [inter‐quartile range 19.5–35] vs. 34 min [25–45], P = < 0.001). SEMS could be deployed successfully with a forward‐viewing endoscope in two patients in whom an initial attempt using side‐viewing endoscope failed. Gastric outlet obstruction scoring system (GOOSS) improved following stent placement (median 0, range 0–2 vs. 2, 0–3, P = 0.0001). The survival of patients undergoing SEMS placement using side‐ and forward‐viewing endoscopes was comparable.

Conclusion

Although side‐ and forward‐viewing endoscopes are equally effective for antroduodenal SEMS placement, the procedure can be performed faster using the latter.

Gallbladder Cancer in the 21st Century

Gallbladder cancer (GBC) is an uncommon disease in the majority of the world despite being the most common and aggressive malignancy of the biliary tree. Early diagnosis is essential for improved prognosis; however, indolent and nonspecific clinical presentations with a paucity of pathognomonic/predictive radiological features often preclude accurate identification of GBC at an early stage. As such, GBC remains a highly lethal disease, with only 10% of all patients presenting at a stage amenable to surgical resection. Among this select population, continued improvements in survival during the 21st century are attributable to aggressive radical surgery with improved surgical techniques. This paper reviews the current available literature of the 21st century on PubMed and Medline to provide a detailed summary of the epidemiology and risk factors, pathogenesis, clinical presentation, radiology, pathology, management, and prognosis of GBC.