Helicobacter Pylori: The Cancer Link

Cancer in Pacific people in New Zealand

PURPOSE

To describe cancer incidence rates among Pacific people living in New Zealand from 1981 to 2004.

METHODS

Linked census-cancer registration data were used to calculate age-standardized cancer incidence rates for Pacific people. Both trends over time within Pacific people and differences in rates between Pacific and European/Other people in New Zealand were assessed.

RESULTS

Pacific rates were higher for cancers of the cervix, endometrium, gallbladder, lip, mouth and pharynx, liver, lung, ovary, pancreas, stomach, and thyroid, and lower for colorectal, bladder, and testicular cancers and melanoma. Differences were large, ranging from a 90 % lower rate of melanoma to over seven times higher rate of liver cancer compared to European/Other. Breast and prostate cancers were the commonest malignancies for Pacific women and men, respectively. Important changes for Pacific women over time include a 64 % decrease in cervical cancer incidence (ptrend = 0.02) and a 245 % increase for lung cancer (ptrend = 0.02), while men had a 366 % increase in prostate cancer (ptrend = 0.02).

CONCLUSIONS

Pacific people in New Zealand have a disproportionate cancer burden related to infectious diseases such as HPV and Hepatitis B. However, with escalating evidence for causal associations between diabetes, obesity, and physical inactivity with various cancers, the challenge will be to prevent these cancers from rising in Pacific people who have the highest rates of these conditions in New Zealand. Disparities for tobacco-related cancers support tobacco consumption as another important cause of cancer incidence disparity. Continued efforts are needed to reduce infectious disease and improve screening program uptake among Pacific people.

[Predictive significance of serum IL-6, VEGF, and CRP in gastric adenoma and mucosal carcinoma before endoscopic submucosal dissection]

BACKGROUND/AIMS

Endoscopic submucosal dissection (ESD) is commonly used for radical resection of gastric adenoma and mucosal cancer, but there is about 30% of discrepancy rate between the histology of the endoscopic biopsy and that of the resected specimen obtained from the same lesion by ESD. The aim of this study was to clarify the clinical significance of IL-6, VEGF, CRP before ESD.

METHODS

We investigated the correlation between serum IL-6, VEGF, CRP level and discrepancy rate of gastric neoplastic lesions (10 low-grade dysplasias, 18 high-grade dysplasias, and 25 early gastic cancers).

RESULTS

Serum levels of IL-6 in gastric adenoma and mucosal cancer patients were significantly higher than in healthy controls (p<0.05). Especially, serum IL-6 level of high-grade dysplasia patient was significantly higher than low-grade dysplasia and mucosal cancer patients, and the positive rate, sensitivity, and negative predictive value of serum IL-6 levels were higher in high-grade dysplasia patient compared to low-grade dysplasia patient and mucosal cancer patient. Serum levels of VEGF in patients with gastric adenoma and mucosal cancer were significantly higher than healthy controls (p<0.01). Serum levels of CRP in patients with mucosal cancer were significantly higher than in the controls (p<0.05), and the positive rate, sensitivity, and positive predictive value of serum CRP levels were higher in high-grade dysplasia and mucosal cancer patients compared to low-grade dysplasia patient.

CONCLUSIONS

Serum levels of IL-6, VEGF, and CRP in patients with gastric neoplastic lesions were significantly higher than healthy controls, especially, serum IL-6 level of high grade dysplasia patient was significantly higher than low-grade dysplasia and mucosal cancer patients.

Introducing infectious agents and cancer

Infectious Agents and Cancer is a new open access, peer-reviewed, online journal, which encompasses all aspects of basic, clinical and translational research that provide an insight into the association between chronic infections and cancer.

Diagnostic role of serum interleukin-18 in gastric cancer patients

AIM: To determine the current status in various aspects of gastric cancer patients and to find out the clinical correlation with prognostic role of serum interleukins in Thai patients.

METHODS: Sixty-eight patients were enrolled in this study at King Chulalongkorn Memorial Hospital during April 2003 to May 2005. Gastric cancer was histologically proven in 51 patients and gastric ulcer in 17 patients. Serum IL-6, IL-10, IL-12, and IL-18 levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS: There were 26 males (55.32%) and 21 females (44.68%) with their age ranging from 33 to 85 years (mean age 64.49 ± 13.83 years). The common presentations were weight loss (41.2%), dyspepsia (39.2%), and upper gastrointestinal bleeding (15.7%). A total of 35.3% gastric cancer patients and 6.3% of gastric ulcer patients were smokers (P = 0.029). Moreover, 32.4% of gastric cancer patients and 6.3% of gastric ulcer patients were alcoholic drinkers (P = 0.044). Lesion location was pyloric-antrum in 39.4%, gastric body in 39.4%, upper stomach in 12.2% and entire stomach in 6.1% of the patients. H pylori infection was detected in 44.4%. The poorly-differentiated adenocarcinoma was the most common pathologic finding (60.7%). Surgical treatment was performed in 44.1% patients (total gastrectomy in 5.9%, subtotal gastrectomy in 32.4% and palliative bypass surgery in 5.9%). Systemic chemotherapy was given as an adjuvant therapy in 8.8% patients. Carcinomatosis peritoneii were found in 18.8% patients. The mean survival time was 13.03 ± 9.75 mo. The IL-18 level in gastric cancer patient group (58.54 ± 43.96 pg/mL) was significantly higher than that in gastric ulcer patient group (30.84 ± 11.18 pg/mL) (P = 0.0001) (95% CI was 42.20, 13.19). The cut point of IL-18 for diagnosis of gastric cancer was 40 pg/mL, the positive predictive value was 92.31%. The IL-6 level in gastric cancer patients with distant metastasis (20.21 ± 9.37 pg/mL) was significantly higher than that in those with no metastasis (10.13 ± 7.83 pg/mL) (P = 0.037) (95% CI was 19.51, 0.65). The role of IL-10 and IL-12 levels in gastric cancer patients was to provide data with no significant difference.

CONCLUSION: These findings demonstrate that serum IL-6 and IL-18, but not IL-10 and IL-12 levels may be the useful biological markers of clinical correlation and prognostic factor in patients with gastric cancer. Moreover, IL-18 could serve as a diagnostic marker for gastric cancer with a high positive predictive value.

Molecular epidemiology, pathogenesis and prevention of gastric cancer

Cancer of the stomach is one of the most commonly diagnosed malignancies and remains an important cause of mortality world wide. This type of cancer is not uniformly distributed among populations but shows a marked variation in both incidence and mortality. Although gastric cancer is declining in many parts of the world, the reasons for this decline are not well understood and its etiology remains unclear. Several factors are suspected to play a role in gastric carcinogenesis, including the effects of diet, exogenous chemicals, intragastric synthesis of carcinogens, genetic factors, infectious agents and pathological conditions in the stomach (such as gastritis). A new look at the results of epidemiological and experimental studies is important for the establishment of strategies for control. Since cancer of the stomach has a very poor prognosis in its more advanced stages, such a control program must have its main focus on primary prevention. This review describes our knowledge about cancer of the stomach regarding epidemiology, pathogenesis and prevention.

Infection, immunity, and cancer

A significant percentage of human cancers worldwide are associated with infections due to known viruses, including human papillomaviruses (cervical cancer and other skin cancers), human T-lymphotropic viruses (adult T-cell leukemias and lymphomas in endemic areas), hepatitis B virus (liver cancer), and Epstein-Barr virus (Burkitt lymphoma and nasopharyngeal carcinoma). The fraction of human cancers attributable to infection may now need to be revised in light of the fact that new viral associations have been discovered and other nonviral associations have been identified. This article addresses the increasingly recognized role of infectious agents as precipitants of human neoplasia and the possibility that novel diagnostic, therapeutic, and chemopreventive strategies may emanate directly from research directed at identifying and understanding these agents.

The relationship between Helicobacter pylori motility, morphology and phase of growth: implications for gastric colonization and pathology

To explore the relationship between Helicobacter pylori motility, morphology and phase of growth, bacteria were isolated from antral biopsies of patients with duodenal ulcer or non-ulcer dyspepsia, and grown in liquid medium in batch and continuous culture systems. Motilities and morphologies of H. pylori in different phases of growth were examined with a Hobson BackTracker and by transmission electron microscopy. Morphologies of bacteria grown in vitro were also compared with those of bacteria in antral biopsies from patients with non-autoimmune gastritis. H. pylori had poor motility in lag phase, became highly motile in mid-exponential phase and lost motility in the decline phase of growth. Motilities of bacteria in the same phase of growth from patients with duodenal ulcer or non-ulcer dyspepsia were not significantly different. In the mid/late-exponential phase of growth bacteria had helical morphologies and multiple polar flagella, typical of H. pylori in the gastric mucus layer. In the decline phase of growth bacteria shed flagella, and had precoccoidal or coccoidal morphologies. These findings support the view that helical and coccoidal H. pylori are in different phases of growth with different roles in gastric colonization, indicate that bacterial motility per se is unlikely to be a determinant of H. pylori pathology, and suggest that H. pylori in the antral mucus layer is in a state of continuous (exponential phase) growth.

Effects of ranitidine bismuth citrate on Helicobacter pylori motility, morphology and survival

AIM

The effects of the anti-ulcer agents ranitidine bismuth citrate (RBC), ranitidine hydrochloride (R) and colloidal bismuth citrate (BC), on Helicobacter pylori motility, morphology and survival were examined to determine whether the clinical effectiveness of RBC might be linked to a specific action that inhibits bacterial motility.

METHODS

H. pylori from patients with duodenal ulcer or non-ulcer dyspepsia were exposed to RBC and BC at bismuth concentrations ranging from 12.5 to 50 microg/mL, and R at ranitidine concentrations ranging from 12.5 to 50 microg/mL for a brief period (< 15 min), 6 h and 24 h. Bacterial motility was assessed with a Hobson BacTracker, bacterial morphology by transmission electron microscopy, and growth inhibition by counting colony-forming units.

RESULTS

H. pylori motility was diminished with RBC and BC but not R. However, the effect of RBC was markedly greater than that of BC at each bismuth concentration and time of exposure tested: (i) brief exposure to RBC/bismuth 50 microg/mL but not to BC, resulted in a significant loss of motility without loss of viability or change in cell morphology, and (ii) bacteria were immobilized, and lost viability after exposure to RBC/bismuth 50 microg/mL for 24 h but not to BC. Morphological destruction caused by RBC differed from that by BC: after 24 h exposure to the highest concentration tested, cell fragmentation and flagella detachment occurred more frequently with BC than RBC, but the latter produced greater disruption of intracellular structures.

CONCLUSIONS

RBC suppresses growth of H. pylori, and has a specific inhibitory effect on the bacterial motor mechanism. These pharmacological actions are likely to contribute to the clinical effectiveness of the agent.

Microbiological and histological study of the gastrointestinal tract of germ-free mice infected with Helicobacter trogontum

Helicobacter spp. have been the focus of considerable research because of the role of this genus in gastrointestinal diseases. We infected NIH germ-free mice with Helicobacter trogontum, a recently described intestinal bacterium of rats, in order to study the distribution of this bacterium in the gastrointestinal tract and the histopathological changes it can induce in this host. Sixteen mice were challenged with a single dose of H. trogontum (test group) and killed one and six weeks after inoculation (eight animals at each point). Eight animals were challenged with 0.85% saline alone (control group) and killed at the same time points (four at each point). Fragments from the gastric and intestinal mucosa were obtained for microbiological and histological examination. H. trogontum was isolated from the cecum and colon of all test mice and also from the gastric mucosa of several of them. All infected animals presented histological changes in at least one region of the bowel. Alterations in the gastric mucosa were also observed mainly in the six-week-infected group. The predominant histological change observed was a moderate diffuse inflammatory infiltrate of mononuclear cells in the lamina propria, often accompanied by a mild infiltration of polymorphonuclear cells. Two animals presented focal infiltration of inflammatory cells in the liver, although no bacteria were found in the liver of any animal. H. trogontum is an intestinal species that is able to elicit inflammatory responses in other regions of the gastrointestinal tract such as the gastric mucosa and the liver of gnotobiotic mice.

Overview of viruses, cancer, and vaccines in concept and in reality

Cancer is a consequence of malfunction of the replicative cell cycle caused by acquisition of independence from proliferative and restrictive controls in the process. Such alteration may be driven by unrepaired mutations in proto-oncogenes and anti-oncogenes or by genetic insults of environmental, infectious, or spontaneous origin. The consequence of mutations may be reflected at any of a number of locations in the transductive pathways from receptor to nucleus which upset normal homeostatic balance between the opposing forces for promotion or restraint of cell proliferation. About 15% of human cancers are caused primarily by viruses that bring about aberrations in gene structure and function or that express proteins that bind to cell regulatory proteins. The means for achieving immunoprophylaxis of viral cancers, such as hepatitis B or Marek's disease, are based on prior specific perturbation of the immune system, causing it to respond rapidly and effectively in preventing infection on subsequent contact with the corresponding agent. Existing cancers of viral origin and those of nonviral causation come together in attempted immunotherapy. Cure is far more difficult to achieve than prevention and relies on the principle that tumor cells can display abnormal markers on the cell surface that are capable of being detected and engaged by an effective immune response. Efforts to prevent and cure cancer of viral, spontaneous, or environmental origin are a worthy pursuit and must take account of the most advanced information relating to the chemistry of the cell cycle and to the function of the immune system.