Helicobacter pylori infection, garlic intake and precancerous lesions in a Chinese population at low risk of gastric cancer.
BACKGROUND: Cangshan County of Shandong Province has one of the lowest rates of gastric cancer (GC) in China. While intestinal metaplasia (IM) and dysplasia (DYS) are less common in Cangshan than in areas of Shandong at high risk of GC, these precursor lesions nevertheless affect about 20% of adults age > or = 55. SUBJECTS AND SETTING: In order to evaluate determinants of IM and DYS in Cangshan County, a low risk area of GC a survey was conducted among 214 adults who participated in a gastroscopic screening survey in Cangshan County in 1994. METHOD: A dietary interview and measurement of serum Helicobacter pylori antibodies were performed. RESULTS: The prevalence of H. pylori was lowest (19%) among those with normal gastric mucosa, rising steadily to 35% for superficial gastritis (SG), 56% for chronic atrophic gastritis (CAG), 80% for IM, and 100% for DYS. The prevalence odds of precancerous lesions were compared with the odds of normal histology or SG. The odds ratio (OR) or CAG associated with H. pylori positivity was 4.2 (95% confidence interval [CI] : 1.7-10.0), while the OR of IM/DYS associated with H. pylori positivity was 31.5 (95% CI: 5.2-187). After adjusting for H. pylori infection, drinking alcohol was a risk factor for CAG (OR = 3.2, 95% CI: 1.1-9.2) and IM/DYS (OR = 7.8, 95% CI: 1.3-47.7). On the other hand, consumption of garlic showed non-significant protective effects and an inverse association with H. pylori infection. CONCLUSIONS: The findings of this study suggest that infection with H. pylori is a risk factor and garlic may be protective, in the development and progression of advanced precancerous gastric lesions in an area of China at relatively low risk of GC. (+info)
Precancerous lesions in two counties of China with contrasting gastric cancer risk.
BACKGROUND: Gastric cancer (GC) is one of the most common cancers worldwide and shows remarkable geographical variation even within countries such as China. Linqu County in Shandong Province of northeast China has a GC rate that is 15 times higher than that of Cangshan County in Shandong, even though these counties are within 200 miles of each other. METHOD: In order to evaluate the frequency of precancerous gastric lesions in Linqu and Cangshan Counties we examined 3400 adults in Linqu County and 224 adults in Cangshan County. An endoscopic examination with four biopsies was performed in each individual of the two populations. RESULTS: The prevalence of intestinal metaplasia (IM) and dysplasia (DYS) was 30% and 15.1%, respectively, in Linqu compared to 7.9% and 5.6% in Cangshan (P < 0.01). Within these histological categories, advanced grades were found more often in Linqu than in Cangshan. The prevalences of IM and DYS were more common at each biopsy site in Linqu, where the lesions also tended to affect multiple sites. CONCLUSIONS: The findings of this study support the concept that IM and DYS are closely correlated with risks of GC and represent late stages in the multistep process of gastric carcinogenesis. (+info)
A blind comparison of the effectiveness of endoscopic ultrasonography and endoscopy in staging early gastric cancer.
BACKGROUND/AIMS: Endoscopic ultrasonography is expected to be useful for invasion depth staging of early gastric cancer. A prospective blind study of the staging characteristics of endoscopy and endoscopic ultrasonography for early gastric cancer was performed. METHODS: Findings of endoscopy and endoscopic ultrasonography using a 20 MHz thin ultrasound probe were independently reviewed and the results of 52 early gastric cancer lesions analysed. RESULTS: The overall accuracy rates in invasion depth staging of early gastric cancer were 63% for endoscopy and 71% for endoscopic ultrasonography. No statistically significant differences were observed in overall accuracy. Endoscopic ultrasonography tended to overstage, and lesions that were classified as mucosal cancer by endoscopic ultrasonography were very likely (95%) to be limited to the mucosa on histological examination. All 16 lesions staged as mucosal cancer independently but coincidentally by both methods were histologically limited to the mucosa. CONCLUSIONS: Endoscopic ultrasonography is expected to compensate for the understaging of lesions with submucosal invasion that are endoscopically staged as mucosal cancer. (+info)
Adenovirus mediated p53 tumour suppressor gene therapy for human gastric cancer cells in vitro and in vivo.
BACKGROUND/AIMS: Gastric cancer is one of the most prevalent forms of cancer in East Asia. Point mutation of the p53 gene has been reported in more than 60% of cases of gastric cancer and can lead to genetic instability and uncontrolled cell proliferation. The purpose of this investigation was to evaluate the potential of p53 gene therapy for gastric cancer. METHODS: The responses of human gastric cancer cell lines, MKN1, MKN7, MKN28, MKN45, and TMK-1, to recombinant adenoviruses encoding wild type p53 (AdCAp53) were analysed in vitro. The efficacy of the AdCAp53 treatment for MKN1 and MKN45 subcutaneous tumours in nude mice was assessed in vivo. RESULTS: p53-specific growth inhibition was observed in vitro in two of four gastric cancer cell lines with mutated p53, but not in the wild type p53 cell line. The mechanism of the killing of gastric cancer cells by AdCAp53 was found, by flow cytometric analysis and detection of DNA fragmentation, to be apoptosis. In vivo studies showed that the growth of subcutaneous tumours of p53 mutant MKN1 cells was significantly inhibited by direct injection of AdCAp53, but no significant growth inhibition was detected in the growth of p53 wild type MKN45 tumours. CONCLUSIONS: Adenovirus mediated reintroduction of wild type p53 is a potential clinical utility in gene therapy for gastric cancers. (+info)
Non-steroidal anti-inflammatory drug-induced apoptosis in gastric cancer cells is blocked by protein kinase C activation through inhibition of c-myc.
Apoptosis plays a major role in gastrointestinal epithelial cell turnover, ulcerogenesis and tumorigenesis. We have examined apoptosis induction by non-steroidal anti-inflammatory drugs (NSAIDs) in human gastric (AGS) cancer cells and the role of protein kinase C (PKC) and apoptosis-related oncogenes. After treatment with aspirin or indomethacin, cell growth was quantified by MTT assay, and apoptosis was determined by acridine orange staining, DNA fragmentation and flow cytometry. The mRNA and protein of p53, p21waf1/cip1 and c-myc was detected by Northern and Western blotting respectively. The influence of PKC on indomethacin-induced apoptosis was determined by co-incubation of 12-O-tetradecanoylphorbol 13-acetate (TPA). The role of c-myc was determined using its antisense oligonucleotides. The results showed that both aspirin and indomethacin inhibited cell growth and induced apoptosis of AGS cells in a dose- and time-dependent manner, without altering the cell cycle. Indomethacin increased c-myc mRNA and protein, whereas p53 and p21wafl/cip1 were unchanged. Down-regulation of c-myc by its antisense oligonucleotides reduced apoptosis induction by indomethacin. TPA could inhibit indomethacin-induced apoptosis and accumulate cells in G2/M. Overexpression of c-myc was inhibited by TPA and p21waf1/cip1 mRNA increased. In conclusion, NSAIDs induce apoptosis in gastric cancer cells which may be mediated by up-regulation of c-myc proto-oncogene. PKC activation can abrogate the effects of NSAIDs by decreasing c-myc expression. (+info)
Peritoneal cytology in the surgical evaluation of gastric carcinoma.
Many patients undergoing surgery for gastric carcinoma will develop peritoneal metastases. A method to identify those patients at risk of peritoneal recurrence would help in the selection of patients for adjuvant therapy. Peritoneal cytology has received little attention in the West, but may prove a useful additional means of evaluating patients with gastric cancer. The aims of this study were to evaluate sampling techniques for peritoneal cytology in patients with gastric cancer, to assess the prognostic significance of free peritoneal malignant cells and to discover the effect of the operative procedure on dissemination of malignant cells. The study is based on 85 consecutive patients undergoing surgical treatment of gastric cancer and followed up for 2 years or until death. Peritoneal cytology samples were collected at laparoscopy, and at operation prior to resection by intraperitoneal lavage and serosal brushings. After resection, samples were taken by peritoneal lavage, imprint cytology of the resected specimen and post-operatively by peritoneal irrigation via a percutaneous catheter. Malignant cells were diagnosed by two independent microscopists. Preoperative peritoneal lavage yielded malignant cells in 16 out of 85 cases (19%). The yield of free malignant cells was increased by using serosal brushings (by four cases) and imprint cytology (by two cases); all of the cases had evidence of serosal penetration. One serosa-negative case exhibited positive cytology in the post-resection peritoneal specimen in which the preresection cytology specimen was negative. Survival was worse in the cytology-positive group (chi2 = 25.1; P< 0.0001). Among serosa-positive patients, survival was significantly reduced if cytology was positive, if cases yielded by brushings and imprint cytology were included (log-rank test = 8.44; 1 df, P = 0.004). In conclusion, free peritoneal malignant cells can be identified in patients with gastric cancer who have a poor prognosis; the yield can be increased with brushings and imprint cytology in addition to conventional peritoneal lavage. Evaluation of peritoneal cytology by these methods may have a role in the selection of patients with the poorest prognosis who may benefit most from adjuvant therapy. (+info)
Microsatellite instability, Epstein-Barr virus, mutation of type II transforming growth factor beta receptor and BAX in gastric carcinomas in Hong Kong Chinese.
Microsatellite instability (MI), the phenotypic manifestation of mismatch repair failure, is found in a proportion of gastric carcinomas. Little is known of the links between MI and Epstein-Barr virus (EBV) status and clinicopathological elements. Examination of genes mutated through the MI mechanism could also be expected to reveal important information on the carcinogenic pathway. Seventy-nine gastric carcinomas (61 EBV negative, 18 EBV positive) from local Hong Kong Chinese population, an intermediate-incidence area, were examined. Eight microsatellite loci, inclusive of the A10 tract of type II transforming growth factor beta receptor (TbetaR-II), were used to evaluate the MI status. MI in the BAX and insulin-like growth factor II receptor (IGF-IIR) genes were also examined. High-level MI (>40% unstable loci) was detected in ten cases (12.7%) and low-level MI (1-40% unstable loci) in three (3.8%). High-level MI was detected in two EBV-associated cases (11%) and the incidence was similar for the EBV-negative cases (13%). The high-level MIs were significantly associated with intestinal-type tumours (P = 0.03) and a more prominent lymphoid infiltrate (P = 0.04). Similar associations were noted in the EBV-positive carcinomas. The high-level MIs were more commonly located in the antrum, whereas the EBV-associated carcinomas were mostly located in body. Thirteen cardia cases were negative for both high-level MI and EBV. All patients aged below 55 were MI negative (P = 0.049). Of the high-level MIs, 80% had mutation in TbetaR-II, 40% in BAX and 0% in IGF-IIR. Of low-level MIs, 33% also had TbetaR-II mutation. These mutations were absent in the MI-negative cases. Of three lymphoepithelioma-like carcinomas, two cases were EBV positive and MI negative, one case was EBV negative but with high-level MI. In conclusion, high-level MIs were present regardless of the EBV status, and were found in a particular clinicopathological subset of gastric carcinoma patient. Inactivation of important growth regulatory genes observed in these carcinomas confirms the importance of MI in carcinogenesis. (+info)
Immunocytochemically detected free peritoneal tumour cells (FPTC) are a strong prognostic factor in gastric carcinoma.
We prospectively investigated the prognostic significance of free peritoneal tumour cells (FPTC) in a series of 118 patients with completely resected gastric carcinoma. Immunocytochemistry with the monoclonal antibody Ber-Ep4 was performed on cytospins from intraoperative peritoneal lavage specimens. Twenty-three patients (20%) had FPTC which was significantly correlated with pT and pN categories, stage, tumour size, lymphatic invasion, Lauren and WHO classifications and perigastric adipose tissue metastases. The median survival time for all FPTC positive compared with negative patients was significantly shorter (11 compared with >72 months), with estimated 5-year survival rates of 8% vs. 60%. None of the patients with FPTC had an early gastric cancer. In advanced tumour subgroups without and with serosal invasion (n = 59 and 35), there were 19% and 34% with FPTC. Multivariate survival analysis showed nodal status, FPTC, mesenteric lymphangiosis, and lymph node metastasis to the compartment III to be independent prognostic factors with relative risks of 6.6, 4.5, 2.9 and 2.2 respectively. Recurrent disease occurred in 91% of FPTC-positive and in 38% of FPTC-negative patients. FPTC had a positive predictive value of 91% and a specificity of 97% for tumour recurrence. FPTC is a strong negative, independent prognostic indicator for survival in gastric carcinoma. (+info)