Fatty acids, biliary bile acids, lipid peroxidation products and gallbladder carcinogenesis:

MAP kinase and mammalian target of rapamycin are main pathways of gallbladder carcinogenesis: results from bioinformatic analysis of next generation sequencing data from a hospital-based cohort (NCT05404347)

BACKGROUND

Gallbladder Cancer (GBC) is one of the most common cancers of the biliary tract and the third commonest gastrointestinal (GI) malignancy worldwide. The disease is characterized by the late presentation and poor outcome despite treatment, and hence, newer therapies and targets need to be identified.

METHODS

The current study investigated various functionally enriched pathways in GBC pathogenesis involving the genes identified through Next Generation Sequencing (NGS) in a hospital-based cohort. The Pathway enrichment analysis and Gene Ontology (GO) were carried out after NGS, followed by the construction of the protein-protein interaction (PPI) network to discover associations among the genes.

RESULTS

Of the thirty-three patients with GBC who were screened through next-generation sequencing (NGS), 27somatic mutations were identified. These mutations involved a total of 14 genes. The p53 and KRAS were commonly found to be mutated, while mutations in other genes were seen in one case each, the mean number of mutations were 1.2, and maximum mutation in a single case (eight) was seen in one case. The bioinformatics analysis identified MAP kinase, PI3K-AKT, EGF/EGFR, and Focal Adhesion PI3K-AKT-mTOR signaling pathways and cross-talk between these.

CONCLUSION

The results suggest that the complex crosstalk between the mTOR, MAPK, and multiple interacting cell signaling cascades can promote GBC progression, and hence, mTOR-MAPK targeted treatment will be an attractive option.

Staging, Treatment, and Future Approaches of Gallbladder Carcinoma

BACKGROUND

Gallbladder cancer is the most common malignant cancer of the bile ducts and third most common gastrointestinal malignant in the world for public health. Its relatively low incidence and confused symptoms result in advanced disease at the time of presentation, contributing to poor prognosis and reduced survival associated with this disease. The main function of the gallbladder is to store excreted bile acids from the liver in preparation for a meal. Its main risk factor is prolonged exposure to biliary calculations, although bacterial infections and other inflammatory conditions are associated. Chronic inflammatory bowel conditions are associated with gallbladder cancer. T stage translates to identifying residual disease at reoperation for incidental gallbladder cancer and residual disease negatively affects survival.

CONCLUSION

It is the most common cancer of gallbladder, gallbladder cancer remains a rare disease. Gallbladder cancer is a rare disease that can be accidentally diagnosed after cholecystectomy or accidentally, often with more advanced disease. The prognosis is generally extremely poor and improvements in surgical resection of this approach have to be re-evaluated, while the role of chemotherapy and radiotherapy remains controversial.

Mitochondria and Reactive Oxygen Species in Aging and Age-Related Diseases

Aging has been linked to several degenerative processes that, through the accumulation of molecular and cellular damage, can progressively lead to cell dysfunction and organ failure. Human aging is linked with a higher risk for individuals to develop cancer, neurodegenerative, cardiovascular, and metabolic disorders. The understanding of the molecular basis of aging and associated diseases has been one major challenge of scientific research over the last decades. Mitochondria, the center of oxidative metabolism and principal site of reactive oxygen species (ROS) production, are crucial both in health and in pathogenesis of many diseases. Redox signaling is important for the modulation of cell functions and several studies indicate a dual role for ROS in cell physiology. In fact, high concentrations of ROS are pathogenic and can cause severe damage to cell and organelle membranes, DNA, and proteins. On the other hand, moderate amounts of ROS are essential for the maintenance of several biological processes, including gene expression. In this review, we provide an update regarding the key roles of ROS-mitochondria cross talk in different fundamental physiological or pathological situations accompanying aging and highlighting that mitochondrial ROS may be a decisive target in clinical practice.

Associations of Calcium and Milk Product Intakes with Incident, Sporadic Colorectal Adenomas

Calcium intake has been consistently, modestly inversely associated with colorectal neoplasms, and supplemental calcium reduced adenoma recurrence in clinical trials. Milk products are the major source of dietary calcium in the United States, but their associations with colorectal neoplasms are unclear. Data pooled from three colonoscopy-based case-control studies of incident, sporadic colorectal adenoma (n = 807 cases, 2,185 controls) were analyzed using multivariable unconditional logistic regression. Residuals from linear regression models of milk with dietary calcium were estimated as the noncalcium, insulin-like growth factor 1-containing component of milk. For total, dietary, and supplemental calcium intakes, the adjusted odds ratios (ORs) comparing the highest to the lowest intake quintiles were 0.94 (95% confidence interval [CI] 0.69-1.30), 0.86 (CI 0.62-1.20), and 0.99 (CI 0.77-1.27), respectively. The corresponding ORs for consumption of total milk products, total milk, nonfat milk, total milk product residuals, and nonfat milk residuals were, respectively, 0.99, 0.90, 0.92, 0.94, and 0.95; all CIs included 1.0. For those who consumed any whole milk relative to those who consumed none, the OR was 1.15 (CI 0.89-1.49). These results are consistent with previous findings of modest inverse associations of calcium intakes with colorectal adenoma, but suggest that milk products may not be associated with adenoma.

Complex APC germline mutation associated metaplasia and intraepithelial neoplasia (CAM-IEN) of the gallbladder

Preneoplasic and neoplastic changes of the gallbladder of patients with a familial adenomatous polyposis (FAP) are rare, and very little is known about their incidence in patients with an attenuated FAP. We herein report on a unique case of a woman with an attenuated FAP who shows eight distinct, partially preneoplastic differentiation patterns within the gallbladder mucosa, which are: (1) regular gallbladder epithelium, (2) low grade biliary intraepithelial neoplasia, (3) papillary adenoma, (4) Paneth cell metaplasia, (5) goblet cell metaplasia, (6) pancreatic metaplasia, (7) pseudopyloric metaplasia, and (8) neuroendocrine differentiation. Moreover, this is the first case of a KRAS mutation in a gallbladder adenoma of a patient with an APC germline mutation, which is highly suggestive of an early event of malignant transformation. As a consequence of our findings, clinicians should draw special attention to the gallbladder of FAP patients, and a simultaneous protective cholecystectomy of FAP patients, which undergo colectomy and show conspicuous changes of the gallbladder mucosa, should be performed in these patients in order to eliminate the risk of a synchronous or metachronous gallbladder neoplasia.

Foods and food groups associated with the incidence of colorectal polyps: the Adventist Health Study

Colorectal cancer (CRC) is a leading cause of cancer death in the United States. The majority of CRC arise in adenomatous polyps and 25-35% of colon adenoma risk could be avoidable by modifying diet and lifestyle habits. We assessed the association between diet and the risk of self-reported physician-diagnosed colorectal polyps among 2,818 subjects who had undergone colonoscopy. Subjects participated in 2 cohort studies: the AHS-1 in 1976 and the AHS-2 from 2002-2005. Multivariate logistic regression analysis was used to estimate the period risk of incident cases of polyps; 441 cases of colorectal polyps were identified. Multivariate analysis adjusted by age, sex, body mass index, and education showed a protective association with higher frequency of consumption of cooked green vegetables (OR 1 time/d vs. <5/wk = 0.76, 95% CI = 0.59-0.97) and dried fruit (OR 3+ times/wk vs. <1 time/wk = 0.76, 95%CI = 0.58-0.99). Consumption of legumes at least 3 times/wk reduced the risk by 33% after adjusting for meat intake. Consumption of brown rice at least 1 time/wk reduced the risk by 40%. These associations showed a dose-response effect. High frequency of consumption of cooked green vegetables, dried fruit, legumes, and brown rice was associated with a decreased risk of colorectal polyps.

Polymorphisms in WNT6 and WNT10A and colorectal adenoma risk

The WNT/β-catenin signaling pathway upregulates transcription of genes involved in cell proliferation and cancer progression; it has been implicated in colorectal adenoma formation. To date, no studies have examined polymorphisms in WNT genes or WNT gene-environment interactions in relation to adenoma risk. Within a colonoscopy-based case-control study of 628 adenoma cases and 516 polyp-free controls, we analyzed two tagSNPs in WNT6 (rs6747776 G > C, rs6754599 G > C) and WNT10A (rs7349332 G > A, rs10177996 A > G). The WNT6 rs6747776 homozygous minor allele (CC) was associated with increased risk of colorectal adenoma (OR = 2.75, 95% CI: 1.03-7.31). We observed a statistically significant interaction between WNT6 rs6747776 and the proportion of calories from total fat (P-int = 0.02), where the highest risk was observed among those with minor alleles and lowest fat intake. We also detected a marginally significant (0.05 < P ≤ 0.10) interaction with fish intake (P-int = 0.09). Additionally, a marginally significant interaction was observed between proportion of calories from saturated fat and the WNT10A rs7349332 polymorphism. Our results suggest that genetic variability in the WNT pathway may play a role in colorectal adenoma formation or may partly mediate the increased risk of colorectal cancer associated with fat intake.

CYP7A1 (-204 A>C; rs3808607 and -469 T>C; rs3824260) promoter polymorphisms and risk of gallbladder cancer in North Indian population

Cholesterol 7-alpha hydroxylase (CYP7A1), which is a rate-limiting enzyme for cholesterol catabolism and bile acid synthesis, may affect cholesterol homeostasis and result in gallstone formation that is a major risk factor for gallbladder cancer (GBC) pathogenesis. Genetic variations in CYP7A1 may influence its expression and thus may affect the risk of gallstone disease and GBC. We aimed to study the association of 2 promoter polymorphisms of CYP7A1 (-204 A>C [rs3808607] and -469 T>C [rs3824260]) in gallstone and GBC susceptibility in North Indian population. The study included 185 GBC patients, 195 symptomatic gallstone patients, and 200 healthy controls. Genotyping for both polymorphisms was done by polymerase chain reaction-restriction fragment length polymorphism method. Although the CC genotype of CYP7A1 -204 A>C was not significantly associated with gallstone disease (P = .083, odds ratio [OR] = 1.69, 95% confidence interval [CI] = 0.9-3.0), it was conferring higher risk for GBC (P = .018, OR = 2.05, 95% CI = 1.1-3.7). However, CYP7A1 -469 T>C was not associated with gallstone disease and GBC risk in our population. After subgroup stratifications on the basis of sex and gallstone status, CC genotype and variant allele of CYP7A1 -204 A>C imparted higher risk for GBC in women (P = .003, OR = 3.30, 95% CI = 1.5-7.2) and patients without gallstones (P = .045, OR = 1.91, 95% CI = 1.2-3.6). Haplotype analysis of the 2 polymorphisms showed that C,T (P = .045, OR = 1.84, 95% CI = 1.0-3.3) and C,C (P = .0001, OR = 3.10, 95% CI = 1.6-6.0) haplotypes had elevated risk of GBC predisposition. CYP7A1 -469 T>C is not associated with gallstone disease or GBC risk. Although CYP7A1 -204 A>C might play a modest role in gallstone susceptibility, it is an independent risk factor for GBC in North Indian population. Underlying mechanism for GBC susceptibility by CYP7A1 (-204 A>C and -469 T>C) haplotype appears to be independent of gallstone pathway and is believed to involve genotoxicity resulting from subnormal bile acid production.

Reproductive factors and risks of biliary tract cancers and stones: a population-based study in Shanghai, China

BACKGROUND

Parity has been linked to gallbladder cancer and gallstones, but the effects of other reproductive factors are less clear.

METHODS

We examined 361 incident biliary tract cancer cases, 647 biliary stone cases, and 586 healthy women in a population-based study in Shanghai.

RESULTS

The effects of parity (odds ratios, OR(> or =3 vs 1 child)=2.0, 95% confidence interval (CI) 0.7-5.1), younger age at first birth (OR(per 1-year decrease)=1.2, 95% CI 0.99-1.6), and older age at menarche (OR(per 1-year increase)=1.4, 95% CI 1.1-1.8) on gallbladder cancer risk were more pronounced among women with stones, but the interactions were not significant.

CONCLUSION

Our results provide support for high parity, younger age at first birth, and late age at menarche in the development of gallbladder cancer, particularly among women with biliary stones.

Dietary meat intake in relation to colorectal adenoma in asymptomatic women

OBJECTIVES

No previous study has concurrently assessed the associations between meat intake, meat-cooking methods and doneness levels, meat mutagens (heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons), heme iron, and nitrite from meat and colorectal adenoma in asymptomatic women undergoing colonoscopy.

METHODS

Of the 807 eligible women in a cross-sectional multicenter colonoscopy screening study, 158 prevalent colorectal adenoma cases and 649 controls satisfactorily completed the validated food frequency and meat questionnaires. Using an established meat mutagen database and new heme iron and nitrite databases, we comprehensively investigated the components of meat that may be involved in carcinogenesis. Using logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) within quartiles of meat-related variables.

RESULTS

Red meat was associated positively with colorectal adenoma (OR fourth vs. first quartile = 2.02; 95% CI = 1.06-3.83; P trend = 0.38). Intake of pan-fried meat (OR = 1.72; 95% CI = 0.96-3.07; P trend = 0.01) and the HCA: 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) (OR = 1.90; 95% CI = 1.05-3.42; P trend = 0.07) were also associated with an increased risk of colorectal adenoma. The new databases yielded lower estimates of heme iron and nitrite than previous assessment methods, although the two methods were highly correlated for both exposures. Although not statistically significant, there were positive associations between iron and heme iron from meat and colorectal adenoma.

CONCLUSIONS

In asymptomatic women undergoing colonoscopy, colorectal adenomas were associated with high intake of red meat, pan-fried meat, and the HCA MeIQx. Other meat-related exposures require further investigation.

Targeted therapies for cancer of the gallbladder

PURPOSE OF REVIEW

Adenocarcinomas of the gallbladder are uncommon, aggressive tumors with poor survival. This review summarizes advances in understanding the biology of gallbladder cancer.

RECENT FINDINGS

Published response rates of adenocarcinomas of the gallbladder to chemotherapy are less than 30% and no survival benefit has been demonstrated from palliative systemic therapy. New information on the molecular carcinogenic mechanisms of these malignancies, combined with findings from animal models, may lead to improved treatment for patients.

SUMMARY

Improved understanding of the molecular carcinogenesis of adenocarcinomas of the gallbladder, coupled with the availability of novel molecularly 'targeted' chemotherapeutic agents, may improve outcome for patients.

Role of genetic variant A-204C of cholesterol 7alpha-hydroxylase (CYP7A1) in susceptibility to gallbladder cancer

Gallbladder carcinoma (GBC) usually arises in the background of gallstone disease. Cholesterol 7alpha-hydroxylase (CYP7A1) is a rate-limiting enzyme for cholesterol catabolism and bile acid synthesis. A-204C genetic polymorphism in CYP7A1 may influence gene expression and thus affect the risk of gallstone disease and GBC. We aimed to study the association of A-204C variation of CYP7A1 gene promoter polymorphism in GBC patients, gallstone patients and healthy subjects. The study included 141 histopathologically proven GBC patients, ultrasonographically proven 185 symptomatic gallstone patients and 200 gallstone-free healthy subjects. Genotyping was done by PCR-RFLP method. CYP7A1 A-204C genotypes in control population were in Hardy-Weinberg equilibrium. The CC genotype conferred marginally significant risk for gallstone disease (p=0.051; OR=1.54; 95% CI=0.9-3.4). In GBC patients, the CYP7A1 A-204C polymorphism conferred high risk for GBC at genotype (p=0.005; OR=2.78; 95% CI: 1.3-5.6) as well as allele levels (p=0.008; OR=1.58 and 95% CI: 1.1-2.2). After stratification of GBC patients on the basis of presence or absence of gallstones, CC genotype imparted higher risk for GBC without stones (p=0.002; OR=4.44: 95% CI=1.7-11.3). The association of the polymorphism with GBC was more pronounced in female GBC patients, and also in cancer patients who developed GBC at advanced age. The CC genotype of CYP7A1 is an independent genetic risk factor for GBC but plays a modest role in susceptibility to gallstone disease. The GBC pathogenesis by CYP7A1 polymorphism appears to be independent of gallstone pathway and probably involves genotoxicity due to lipid peroxidation mechanisms.

Electrophoretic pattern of proteins in carcinoma of the gallbladder

Carcinoma of the gallbladder is a common health problem in the northern region of India and in spite of improved diagnostic techniques it is generally diagnosed at an advanced stage. This study was carried out in 60 patients, 30 of whom were diagnosed with gallbladder carcinoma and 30 with cholelithiasis. The protein content in tissue extracts and serum was determined using the Folin method of Lowry. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis was performed for the identification of proteins according to Laemmli. The results showed the mean concentration of total protein in gallbladder tissue of patients with carcinoma of the gallbladder was 51.83 +/- 3.36 mg/g tissue (45.33-57.80) and in patients with cholelithiasis it was 38.82 +/- 9.11 mg/g tissue (29.55-50.99) (P<0.001). Protein electrophoresis of gallbladder tissue from the patients with carcinoma of the gallbladder showed three additional bands of protein (two protein bands were present in the region of 50-55 kDa and the third band was present in the region of 35 kDa), which were absent in the gallbladder tissue of cholelithiasis patients. Mean total protein content in serum was 72.2 +/- 1.73 g/l (67.98-74.99) in patients of carcinoma of the gallbladder, whereas it was 71.01 +/- 3.4 g/l (60.00-78.99) (P>0.05) in the patients with cholelithiasis. Electrophoretic analysis of serum protein revealed at least two additional protein bands in patients with carcinoma of the gallbladder as compared with electrophoretic pattern in cholelithiasis. These two bands were in the range of 80 and 25 kDa proteins. In conclusion, the presence of these new bands of protein in the gallbladder tissue and serum of the patients with carcinoma of the gallbladder indicate their role in the pathogenesis of the carcinoma of the gallbladder.

Body fluid proteomics: Prospects for biomarker discovery

Many diseases are caused by perturbations of cellular signaling pathways and related pathway networks as a result of genetic aberrations. These perturbations are manifested by altered cellular protein profiles in the fluids bathing tissue/organs (i.e., the tissue interstitial fluid, TIF). A major challenge of clinical chemistry is to quantitatively map these perturbed protein profiles - the so-called "signatures of disease" - using modern proteomic technologies. This information can be utilized to design protein biomarkers for the early detection of disease, monitoring disease progression and efficacy of drug action. Here, we discuss the use of body fluids in the context of prospective biomarker discovery, and the marked 1000-1500-fold dilution of body fluid proteins, during their passage from TIF to the circulatory system. Further, we discuss proteomics strategies aimed at depleting major serum proteins, especially albumin, in order to focus on low-abundance protein/peptides in plasma. A major limitation of depletion strategies is the removal of low-molecular weight protein/peptides which specifically bind major plasma proteins. We present a prototype model, using albumin, for understanding the multifaceted nature of biomarker research, highlighting the involvement of albumin in Alzheimer's disease. This model underscores the need for a system-level understanding for biomarker research and personalized medicine.

The effect of lactose maldigestion on the relationship between dairy food intake and colorectal cancer: a systematic review

Dairy food consumption has been inconsistently shown to protect against colorectal cancer (CRC) in case-based studies, and no clear benefits against recurrent colonic polyps (CRP) have been reported. Based on population-based studies we have hypothesized that dairy food intake may have anti-CRC effects at both low intake lactase non-persistent (LNP) populations and at high intake lactase persistent (LP) subjects. We separately analyse existing case-based studies and divide origins into high LNP (>or= 80% LNP prevalence), low LNP (prevalence <or= 20%) and mid LNP countries (21-79% prevalence), which coincide with low, high, and mid quantity dairy food intake regions, respectively. Odds ratios and relative risks (RR) of highest versus lowest dairy intake within each group are analyzed together for assessment of protection against CRC and CRP. Eighty studies met stipulated criteria. Thirteen analyzed the effect on recurrent polyps. Forest plots from 2 regions, high LNP (low dairy food intake) RR = 0.84 [95% confidence interval (CI) = 0.73-0.97) and low LNP (high dairy food intake) RR = 0.80 (95% CI = 0.73-0.88) demonstrated significant protection against CRC. In mixed LNP/LP populations (mid dairy food intake) nonsignificant protection was found RR = 0.92 (95% CI = 0.79-1.06). Similar regional analysis for CRP failed to show significant protective effect in any region. This meta-analysis supports that the highest level of dairy food consumption protects subjects in both high and low LNP regions but not in areas with significant mixed LNP/LP populations. In both groups, dairy foods had no effect on polyp formation, suggesting it may only protect against CRC at late stages of promotion. These results raise the possibility that LNP/LP status may be partly responsible for the discrepant results with respect to the relationship between dairy food consumption and CRC.

Environmental pollutants in gallbladder carcinogenesis

Gallbladder cancer is a common malignancy of the gastrointestinal tract that shows wide geographical variation in its distribution. Cause of gallbladder cancer is still obscure; however, various etiological factors have been proposed. Of these gallstones and inflammation of the gallbladder is commonest. Despite three decades of active research no conclusive evidence is available as to what causes gallbladder cancer? In this article we reviewed the evidence on the role of environmental pollutants on gallbladder carcinogenesis. A detailed search of Medline was carried out which revealed only 12 articles. A number of heavy metals like nickel, cadmium, etc. have been implicated; however, the evidence is not robust enough to conclude its association. Role of radiation and pesticides in river water have also been evaluated without any conclusive evidence of its association with gallbladder cancer. Better designed case-control studies or cohort studies looking at exposure are required before it could be accepted as one of the causes of GBC.

Milk Consumption in Relation to Incidence of Prostate, Breast, Colon, and Rectal Cancers: Is There an Independent Effect?

Milk contains a wide variety of ingredients, such as nutrients, hormones, and chemical contaminants. Whether milk consumption is associated with the risk of prostate, breast, colon, and rectal cancers is unclear and was evaluated in this study. Data on milk consumption for 9 time periods (1964-1994) and incidence rates of prostate, female breast, colon, and rectal cancers, mostly around 1993-1997, in 38 countries were obtained from the Food and Agriculture Organization and World Health Organization, respectively. Milk consumption was strongly correlated with incidence rates of prostate cancer (r = 0.65-0.69; all P < 0.0001) and breast cancer (r = 0.64-0.74; all P < 0.0001) in all the nine time periods examined. A modest positive correlation was found for colon and rectal cancers in both sexes (all P < 0.05, except for rectal cancer in the first three time periods). The previous findings remained essentially unchanged after adjustment for vegetable, alcohol, and cigarette consumption but disappeared after further adjustment for non-milk fat consumption, except for breast cancer in the last three time periods. The present study does not support an overall substantial effect of milk consumption on the risk of prostate, breast, colon, and rectal cancers at the population level.

Changes in Diet During Adult Life and Risk of Colorectal Adenomas

To evaluate the associations of changes in diet during adult life with adenoma risk, data from a case-control study of 146 colorectal adenomas and 226 controls were analyzed. Dietary habits during the year before sigmoidoscopy and when subjects were 30 yr old were collected using a food-frequency questionnaire. Change in frequency of consumption during adulthood was calculated by subtracting frequency of consumption of specific foods or food groups at age 30 yr from frequency of consumption during the previous year (recent consumption). Associations with changes in frequency of consumption were estimated by odds ratios (ORs) and 95% confidence intervals (CIs). There was no association for foods or food groups consumed at age 30 yr. For recent consumption, more frequent consumption of red meat, breakfast sausage, and pork chops/ham steaks and less frequent consumption of fish, chicken/turkey, and vegetables were related to a higher risk. Compared with individuals with the highest reduction in consumption since age 30 yr, risks were higher for those with smallest reduction in red meat intake (OR = 2.8; CI = 1.1-7.3), particularly for hamburgers/cheeseburgers (OR = 2.8; CI = 1.2-6.8) and pork chops/ham steaks (OR = 3.7; CI = 1.6-8.7). In contrast, individuals in the highest quartile of increased consumption of fish (OR = 0.6; CI = 0.3-1.1) and vegetables (OR = 0.5; CI = 0.3-1.1) had a lower risk compared with those with minimal increase in consumption. In conclusion, irrespective of frequency of consumption at age 30 yr, a greater reduction in consumption of red meat and a larger increase in consumption of vegetables since age 30 yr were associated with a decreased risk of colorectal adenomas later in life.

Egg Consumption and Mortality From Colon and Rectal Cancers: An Ecological Study

The relation between egg consumption and mortality from colon and rectal cancers remains unclear and was investigated in this study. Colon and rectal cancer mortality data, mostly around 1993-94 and egg consumption data in nine time periods (1964-94) in 34 countries were derived from World Health Organization and Food and Agriculture Organization, respectively. Egg consumption was significantly and positively correlated with mortality from colon and rectal cancers in both sexes in most of the nine time periods. The correlations were generally stronger for colon cancer (r = 0.39 to 0.63 in men and r = 0.33 to 0.65 in women) than for rectal cancer (r = 0.18 to 0.49 in men and r = 0.08 to 0.45 in women). After adjustment for confounding factors, egg consumption was still significantly and positively associated with mortality from colon cancer in the earliest five time periods (1964-84) (P = 0.046 to 0.017 in men and P = 0.034 to 0.014 in women) and rectal cancer in the latest five time periods except for the last time period (1982-91) (P = 0.046 to 0.024 in men and P = 0.045 to 0.026 in women). This study suggested that egg consumption was associated with an increased risk of colon and rectal cancers at the population level

Carcinoma of the gallbladder

Carcinoma of the gallbladder is the most common malignant tumour of the biliary tract and a particularly high incidence is observed in Chile, Japan, and northern India. The aetiology of this tumour is complex, but there is a strong association with gallstones. Owing to its non-specific symptoms, gallbladder carcinoma is generally diagnosed late in the disease course, but if a patient with gallstones experiences a sudden change of symptoms, then a cancer diagnosis should be considered. Treatment with radical or extended cholecystectomy is potentially curative, although these procedures are only possible in 10-30% of patients. There is no role for cytoreductive surgery in this disease. If a gallbladder carcinoma is discovered via pathological examination of tissue samples, then the patient should be examined further and should have radical surgery if the tumour is found to be T1b or beyond. Additional port-site excision is necessary if the patient has already had their gallbladder removed during laparoscopy; however, patients with an intact gallbladder who are suspected to have gallbladder carcinoma should not undergo laparoscopic cholecystectomy. Patients with advanced inoperable disease should receive palliative treatment; however, the role of chemotherapy and radiation in these patients needs further evaluation.

Cytochrome P-450 expression and lipid peroxidation in gallbladder cancer

BACKGROUND AND OBJECTIVES

Carcinoma of the gallbladder is the commonest neoplasm of the biliary tract; however, the etiology of this tumor remains unclear.

METHODS

A case-control study was carried out comprising 50 patients with gallbladder cancer and 50 patients with cholelithiasis. Cytochrome P-450 estimation was carried out in the gallbladder tissue, and lipid peroxide product melonaldehyde (MDA) was measured in gallbladder bile. Statistical analysis was carried out by Student's t-test, and one-way analysis of variance (ANOVA). The Pearson correlation coefficient was calculated, and linear regression analysis was performed.

RESULTS

The mean cytochrome P-450 concentration was significantly higher in patients with carcinoma of the gallbladder than in controls (t = 3.9, P < 0.001; F = 15.2, P = 0.002). Similarly, the mean concentration of melonaldehyde was significantly higher among cancer patients than in patients with gallstones (t = 2.7, P < 0.003; F = 7.37, P = 0.0078). No significant correlation was observed between tissue MDA and cytochrome P-450 levels (Pearson r = 0.1, P = 0.28).

CONCLUSIONS

The results of the present study show that the rise in concentration of MDA is independent of the rise in concentration of cytochrome P-450; however, this is statistically insignificant. This could be due to biliary stasis leading to a rise in biliary concentration of melonaldeyde that is disproportionate to its production.

Risk factors for gallbladder cancer: a reappraisal

Carcinoma of the gallbladder has a very unusual geographical distribution with pockets of high incidence seen in Chile, Poland, India, Japan and Israel; it occurs rarely in the rest of the world. It is a common malignancy in the Western Bihar and Eastern Uttar Pradesh regions of India. Patients present with extremes of clinical symptoms, indicating benign biliary diseases on the one hand and incurable malignant disease on the other. Laboratory and roentgenographic data tend to confirm the clinical diagnosis of the advanced incurable disease at presentation, in most cases. Various aetiopathological agents have been proposed but none has stood the test of time. In this article, we have reviewed the aetiopathological agents proposed from time to time over the past two centuries, with special emphasis on the developments made in the last 25 years.

Diet and gallbladder cancer: a case-control study

Cancer of the gallbladder is rare but fatal, and has an unusual geographic and demographic distribution. Gallstones and obesity have been suggested as possible risk factors. As diet is known to influence both these factors, we carried out the present study to evaluate the possible role of diet in gallbladder carcinogenesis. A case-control study involving 64 newly diagnosed cases of gallbladder cancer and 101 cases of gallstones was carried out. The dietary evaluation was carried out by the dietary recall method based on a preset questionnaire developed specifically for the present study, keeping in mind the common dietary habits prevailing in this part of the world. Odds ratios (OR) and 95% confidence interval (CI) were calculated for various dietary items. A significant reduction in odds ratio was seen with the consumption of radish (OR 0.4; 95% CI 0.17-0.94), green chilli (OR 0.45; 95% CI 0.21-0.94) and sweet potato (OR 0.33; 95% CI 0.13-0.83) among vegetables, and mango (OR 0.4; 95% CI 0.16-0.99), orange (OR; 0.45; 95% CI 0.22-0.93), melon (OR 0.3; 95% CI 0.14-0.64) and papaya (OR 0.44; 95% 0.2-0.64) among fruits. A reduction in odds was also seen with the consumption of cruciferous vegetables, beans, onion and turnip, however the difference was not statistically significant. On the other hand, an increase in the odds was observed with consumption of capsicum (OR 2.2), beef (OR 2.58), tea (OR 1.98), red chilli (OR 1.29) and mutton (OR 1.2), however the difference was statistically not significant. In conclusion, the results of the present study show a protective effect of vegetables and fruits on gallbladder carcinogenesis, but red meat (beef and mutton) was found to be associated with increased risk of gallbladder cancer.

Biliary lipid peroxidation products in gallbladder cancer: increased peroxidation or biliary stasis?

Gallbladder cancer is a common malignancy among women in India. The aetiology of gallbladder carcinoma is still obscure and although numerous factors have been implicated, none has stood the test of time. This study was carried out to evaluate the role of lipid peroxidation product 4-hydroxynonenal (HNE) in gallbladder carcinogenesis. High-performance liquid chromatography (HPLC) analysis was carried out in 30 bile samples obtained during laparotomy from patients with gallbladder cancer (n = 10), cholelithiasis (n = 10) and age- and sex-matched controls (n = 10). A significantly high concentration of HNE and lower concentration of biliary pH and electrolyte was observed in patients with carcinoma of the gallbladder compared with controls and patients with cholelithiasis. A significant correlation was also observed between biliary Na+ and K+ (r = 0.72), biliary Ca2+ and Na+ (r = 0.69) among controls. However, there was no correlation between HNE, electrolytes and pH among cancer patients. An increased concentration of biliary HNE and decreased concentration of electrolytes suggest biliary stasis rather then increased peroxidation in cancer patients.