Cholesterol gallstones and cancer of gallbladder (CAGB): molecular links

Mediterranean diet and olive oil, microbiota, and obesity-related cancers. From mechanisms to prevention

Olive oil (OO) is the main source of added fat in the Mediterranean diet (MD). It is a mix of bioactive compounds, including monounsaturated fatty acids, phytosterols, simple phenols, secoiridoids, flavonoids, and terpenoids. There is a growing body of evidence that MD and OO improve obesity-related factors. In addition, obesity has been associated with an increased risk for several cancers: endometrial, oesophageal adenocarcinoma, renal, pancreatic, hepatocellular, gastric cardia, meningioma, multiple myeloma, colorectal, postmenopausal breast, ovarian, gallbladder, and thyroid cancer. However, the epidemiological evidence linking MD and OO with these obesity-related cancers, and their potential mechanisms of action, especially those involving the gut microbiota, are not clearly described or understood. The goals of this review are 1) to update the current epidemiological knowledge on the associations between MD and OO consumption and obesity-related cancers, 2) to identify the gut microbiota mechanisms involved in obesity-related cancers, and 3) to report the effects of MD and OO on these mechanisms.

An overview on possible links between aflatoxin B1 exposure and gallbladder cancer

Gallbladder cancer (GBC) is one of the most common sites for biliary tract cancers. It has a worldwide distribution being endemic in South America and Southern Asia. These high GBC rates have previously been linked to the determinants of health such as nutrition, genetics, lifestyle, and environment. Exposure to aflatoxin B₁ (AFB₁), a human carcinogen, is suggested to be involved with GBC development. This work aims to analyse the interplay of social, lifestyle, and genetic predisposing factors to GBC. AFB₁ plays a pivotal role in carcinogenic onset by genetic and epigenetic modifications. AFB₁ can induce molecular changes involved in the GBC pathogenesis, such as overexpression of UCHL1 gene, mutagenesis of TP53 gene, abnormal expression of oncogenes BCL-2, and aberrantly methylation of ERBB family receptors. However, a large-scale scientific cooperation is needed to confirm these molecular links through which AFB₁ may increase the GBC risk. For that, monitoring AFB₁ exposure through AF-albumin and AFB1-lysine will clarify the level of exposure of the population to AFB₁ in the GBC hotspot. Further, analyses of AFB1-adduct concentrations in GBC cases (fatal and non-fatal) are needed to understanding if AF contamination can trigger gallbladder cancer.

Cadmium exposure activates Akt/ERK Signaling and pro-inflammatory COX-2 expression in human gallbladder epithelial cells via a ROS dependent mechanism

Gallbladder cancer (GBC) is the commonest biliary tract cancer with an ill-defined etiology. We examined the role of Cd⁺² exposures in a primary human gallbladder (GB) cell line model in this study. Cd⁺² exposures induced decreased cell viability, reactive oxygen species (ROS) generation, altered Akt/ERK signaling pathway activation, PGE₂ and COX-2 expression in a human primary gallbladder epithelial cell model. Pharmacological inhibitors were used to determine the key drivers of elevated COX-2 expression due to Cd⁺² exposure. Our results show Cd⁺² causes a dose-dependent reduction in GB cell viability (EC50 value - 18.6 μM). Dose-dependent activation of phospho-Akt and phospho-ERK signaling pathways via increased phosphoprotein expression was observed due to Cd⁺². Signaling activation of Akt and ERK was prevented by 5 mM N-Acetyl Cysteine (NAC), establishing the role of ROS as a key driver in the activation process. Importantly, we observed Cd⁺² also caused a dose dependent change in the COX-2 and PGE₂ expression levels. PI3K-Akt and NF-kB signaling pathways play a key role in Cd⁺² exposure induced COX-2 activation in the gallbladder epithelial cells. In conclusion, our study measures the toxicological effects of Cd⁺² exposures on human GB epithelial cells for the first time and establishes the role of Cd⁺² as a possible driver of the Akt/ERK pathway overactivity and chronic inflammation in gallbladder carcinogenesis.

[Clinical, epidemiological and therapeutic features of biliary tract cancers: about 20 cases]

Biliary tract cancers mainly occur in two sites: gallbladder cancer which are adenocarcinomas and intra- and extrahepatic cholangiocarcinomas. We conducted a retrospective study of 20 cases with biliary tract cancer in the Department of Surgery at the General Hospital in Grand-Yoff between January 2006 and October 2014. 40% of patients had gallbladder cancer, 60% of patients had common bile duct cancer. Sex ratio was 1. The average age of patients was 58.1 years. The average time to diagnosis was 3.77 months. Symptomatology was dominated by icteric syndrome and right hypochondrium pain. All patients had biological manifestation of cholestatic syndrome. Abdominal ultrasound was performed in 65% of patients, while abdominal CT scan in 85% of cases and MRI in 35% of cases. Advanced cancers were predominant in our case series (n=19). The majority of patients underwent palliative surgery. The most practiced treatment was biliary diversion (50% of patients). There was a predominance of cholangiocarcinomas. The overall operative morbidity rate was 43.75%. The overall mortality rate in our patients with biliary tract cancers of any site was 31.25%. Median survival was 4 months and a half. Biliary tract cancers have multifaceted features and can be differentiated essentially among intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, gallbladder adenocarcinoma whose evolution is globally different but the prognosis is spontaneously poor.

[Role of biliary MRI in etiological diagnosis of cholestatic icteruses in Dakar]

Biliary MRI is a relatively new diagnostic test in the arsenal of exploration techniques in biliopancreatic pathology. This is a reproducible and reliable non invasive technique for direct visualization of biliary and pancreatic ducts. This study aims to evaluate the morphological features of major abnormalities and the role of biliary MRI in the etiological diagnosis of cholestatic icteruses. This is a retrospective study of 17 patients conducted in the Imaging Unit of the University Hospital of Fann and of the Principal hospital of Dakar over a period of 4 years and six months (January 2008 at July 2012). All patients underwent MRI (1.5T) according to the standardized protocols for the explored pathology. Only medical records of patients whose diagnosis was established based on laboratory tests and who underwent biliary MRI and surgical exploration were retained. The study involved 5 women and 12 men with a sex ratio of 2.4. The average age of patients was 58 years, ranging between 35 and 81 years. Klatskin tumors were found in 7 patients with infiltrative form in 71% of cases and exophytic form was found in 28% of cases. Cancers of the gallbladder were found in 28% of cases. Cancers in the head of the pancreas accounted for 28% of cases. Major bile duct lithiasis was detected in 5 patients, choledocholithiasis in 60% of cases and a single lithiasis in 40% of cases. All these lesions were responsible for an expansion of intrahepatic bile duct (IHBD). One case of intra and extrahepatic bile ducts dilatation was found without biliopancreatic cause. Biliary MRI is the test of choice for the exploration of cholestatic icteruses. It should be recommended as first-line examination when residual lithiasis is suspected and as second-line examination after ultrasound, when the latter shows a suspected bile ducts tumoral obstruction. Its association with CT scan is the best combination of screening tests for etiologic diagnosis and pre-operative assessment of tumoral biliary obstructions.

Modern perspectives on factors predisposing to the development of gallbladder cancer

BACKGROUND

Gallbladder cancer (GBC) is a rare malignancy, yet certain groups are at higher risk. Knowledge of predisposing factors may facilitate earlier diagnosis by enabling targeted investigations into otherwise non-specific presenting signs and symptoms. Detecting GBC in its initial stages offers patients their best chance of cure.

METHODS

PubMed was searched for recent articles (2008-2012) on the topic of risk factors for GBC. Of 1490 initial entries, 32 manuscripts reporting on risk factors for GBC were included in this review.

RESULTS

New molecular perspectives on cholesterol cycling, hormonal factors and bacterial infection provide fresh insights into the established risk factors of gallstones, female gender and geographic locality. The significance of polyps in predisposing to GBC is probably overstated given the known dysplasia-carcinoma and adenoma-carcinoma sequences active in this disease. Bacteria such as Salmonella species may contribute to regional variations in disease prevalence and might represent powerful targets of therapy to reduce incidences in high-risk areas. Traditional risk factors such as porcelain gallbladder, Mirizzi's syndrome and bile reflux remain important as predisposing factors.

CONCLUSIONS

Subcentimetre gallbladder polyps rarely become cancerous. Because gallbladder wall thickening is often the first sign of malignancy, all gallbladder imaging should be scrutinized carefully for this feature.

Potential therapeutic targets for the primary gallbladder carcinoma: estrogen receptors

Gallbladder carcinoma, the most frequent malignant neoplasm of the biliary tract system, has always been considered to feature late clinical presentation and diagnosis, limited treatment options and an extremely poor prognosis. In recent years, while the incidence of gallbladder cancer has appeared to be on the increase, the available treatment methods have not greatly improved survival of the affected patients. Thus, exploring new therapeutic targets for this devastating disease is an urgent matter at present. Epidemical studies have demonstrated that the incidence of gallbladder carcinoma exhibits a distinct gender bias, affecting females two to three times more than males, pointing to crucial roles of estrogen. It is well known that estrogen acts on target tissues by binding to estrogen receptors (ERs), which are mainly divided into three subtypes, ERα, ERβ and ERγ. ERα and ERβ appear to have overlapping but also unique even opposite biological effects. As important pathogenic mediators, ERs have been considered to relate to several kinds of tumors. In gallbladder carcinoma tissue, ERs have been shown to be positively expressed, and ERs expression levels are associated with differentiation and prognosis of this cancer. Nevertheless, the exact mechanisms of estrogen inducing growth of gallbladder carcinoma remain poorly understood. On the base of the current investigations, we deduce that estrogen participates in promotion of gallbladder carcinoma by influencing the formation of gallstones, stimulating angiogenesis, and promoting abnormal proliferation. Since ERs mediate the carcinogenic actions of estrogen in gallbladder, and therapy targeting ERs may provide new directions for gallbladder carcinoma. Therefore, it should be stressed that ERs are potential therapeutic targets for gallbladder carcinoma.

Gallbladder carcinoma in a pregnant patient with Crohn's disease complicated with gallbladder involvement

Primary gallbladder (GB) carcinoma and Crohn’s disease (CD) of the GB are individually rare. We present a case of a pregnant woman with CD found to have GB involvement and primary GB carcinoma. A 34-year-old female at 6 wk gestation with a 21 year history of CD of uncertain extent presented with 3 mo of diarrhea, urgency and abdominal pain. During work-up, she was found to have elevated transaminases and an abnormal alkaline phosphatase. Imaging revealed two gallbladder polyps both greater than 1 cm in size. Resection and histological evaluation was consistent with Crohn’s involvement of the GB, poorly differentiated adenocarcinoma of the GB with invasion through the muscularis propria and matted lymph nodes in the porta hepatis positive for metastatic carcinoma (stage pT2N1). Six cases of CD involving the GB, two cases of primary GB carcinoma in CD, and ten cases of cholangiocarcinoma in pregnancy have been published. This is the only case that describes all three factors. Common features in CD of the GB include acute cholecystitis, ileal involvement, and presence independent of active intestinal disease. Common features in CD patients with GB malignancy include younger age of detection, a long history of CD, extensive colonic and ileal involvement of disease, the absence of cholelithiasis, and pre-existing gallbladder disease (primary sclerosing cholangitis and gallbladder polyps). Pregnancy is specific to this case. The role of CD in the development of GB malignancy is not well understood nor is the contribution of pregnancy to the spread of disease. Chronic inflammation and immunosuppression compounded by hormonal influence is implicated.

Diagnosis and management of gallbladder cancer

Gallbladder cancer (GBC) is a rather uncommon disease, but at the time when it gives symptoms it has usually reached no longer curable stage. Therefore, all attempts must be made to make the diagnosis earlier to have better opportunity for cure. The author searched PubMed, and reviewed literatures on diagnoses and treatment of GBC.

Epidemiology of gallbladder disease: cholelithiasis and cancer

Diseases of the gallbladder are common and costly. The best epidemiological screening method to accurately determine point prevalence of gallstone disease is ultrasonography. Many risk factors for cholesterol gallstone formation are not modifiable such as ethnic background, increasing age, female gender and family history or genetics. Conversely, the modifiable risks for cholesterol gallstones are obesity, rapid weight loss and a sedentary lifestyle. The rising epidemic of obesity and the metabolic syndrome predicts an escalation of cholesterol gallstone frequency. Risk factors for biliary sludge include pregnancy, drugs like ceftiaxone, octreotide and thiazide diuretics, and total parenteral nutrition or fasting. Diseases like cirrhosis, chronic hemolysis and ileal Crohn's disease are risk factors for black pigment stones. Gallstone disease in childhood, once considered rare, has become increasingly recognized with similar risk factors as those in adults, particularly obesity. Gallbladder cancer is uncommon in developed countries. In the U.S., it accounts for only ~ 5,000 cases per year. Elsewhere, high incidence rates occur in North and South American Indians. Other than ethnicity and female gender, additional risk factors for gallbladder cancer include cholelithiasis, advancing age, chronic inflammatory conditions affecting the gallbladder, congenital biliary abnormalities, and diagnostic confusion over gallbladder polyps.

Cholelithiasis in gallbladder cancer: coincidence, cofactor, or cause!

BACKGROUND

While gallstones are associated with cancers of the gallbladder, the actual nature of their relationship needs to be clarified. This would aid the recommendations on the need for prophylactic cholecystectomy.

METHODS

A systematic search of the scientific literature was carried out using the Medline, the Embase, and the Cochrane Central Register of Controlled Trials for the years 1891-2009 to obtain access to all publications involving gallstones in gallbladder cancer.

RESULTS

While some epidemiological evidence supports a causal relationship for gallstones in gallbladder cancer, other studies have demonstrated a relatively low incidence of gallbladder cancer in countries reporting a high incidence of gallstones as a whole. In those studies where gallstones appear to have a causative role for cancer, the risk increases with increasing size, volume and weight, and number of the stones. The impact of duration of the stone or its composition is not clear. Experimental evidence from studies examining the impact of artificially introducing gallstones in the gallbladder has failed to lead to carcinogenesis.

CONCLUSIONS

The evidence at the current time indicates that gallstones are a cofactor in the causation of gallbladder cancer. Absolute proof of their role as a cause for gallbladder cancer is lacking. The recommendation for prophylactic cholecystectomy in countries reporting a high incidence of gallbladder cancer and associated gallstones needs to be tailored to the epidemiological profile of the place.