(1/1094) Hybrid capture II, a new sensitive test for human papillomavirus detection. Comparison with hybrid capture I and PCR results in cervical lesions.
AIM: To test a new assay for the detection of human papillomavirus (HPV) DNA, hybrid capture II (HC II), compared with the previous commercialized hybrid capture I (HC I) and polymerase chain reaction (PCR) results on cervical scrapes from fresh cone excision biopsy samples. METHODS: The three methods were used on cervical scrapes from 42 fresh cone excision biopsy samples. There were nine metaplastic and inflammatory lesions, five low grade lesions, and 28 high grade lesions. PCR was performed using the general primers GP5+/GP6+. The viral load of high risk HPV DNA was estimated by the ratio of relative light units to positive control values in the samples. RESULTS: The sensitivity of HC I for the detection of high grade lesions was 71.4%, while it was 92.8% for HC II and 96.4% for the PCR. Considering only the absence of detectable cervical in situ neoplasia, the specificity was 88.9% for HC I, 66.7% for HC II, and 66.7% for PCR. With HC II, for a ratio of cervical sample to normal control of > 200, the sensitivity for the detection of high grade lesion was only 34.6% with a specificity of 66.7%. CONCLUSIONS: HPV detection with the HC II assay is more sensitive than the previous HC I and represents a more convenient and easier test than PCR for routine use. Nevertheless the viral load estimated with this test cannot be a reliable predictive indicator of high grade lesions. (+info)
(2/1094) 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)
(3/1094) KRAS mutations predict progression of preneoplastic gastric lesions.
Eight hundred sixty-three subjects with atrophic gastritis were recruited to participate in an ongoing chemoprevention trial in Narino, Colombia. The participants were randomly assigned to intervention therapies, which included treatment to eradicate Helicobacter pylori infection followed by daily dietary supplementation with antioxidant micronutrients in a 2 x 2 x 2 factorial design. A series of biopsies of gastric mucosa were obtained according to a specified protocol from designated locations in the stomach for each participant at baseline (before intervention therapy) and at year three. A systematic sample of 160 participants was selected from each of the eight treatment combinations. DNA was isolated from each of these biopsies (n = 320), and the first exon of KRAS was amplified using PCR. Mutations in the KRAS gene were detected using denaturing gradient gel electrophoresis and confirmed by sequence analysis. Of all baseline biopsies, 14.4% (23 of 160) contained KRAS mutations. Among those participants with atrophic gastritis without metaplasia, 19.4% (6 of 25) contained KRAS mutations, indicating that mutation of this important gene is likely an early event in the etiology of gastric carcinoma. An important association was found between the presence of KRAS mutations in baseline biopsies and the progression of preneoplastic lesions. Only 14.6% (20 of 137) of participants without baseline KRAS mutations progressed from atrophic gastritis to intestinal metaplasia or from small intestinal metaplasia to colonic metaplasia; however, 39.1% (9 of 23) with baseline KRAS mutations progressed to a more advanced lesion after 3 years [univariate odds ratio (OR), 3.76 (P = 0.05); multivariate OR adjusted for treatment, 3.74 (P = 0.04)]. In addition, the specificity of the KRAS mutation predicted progression. For those participants with G-->T transversions at position 1 of codon 12 (GGT-->TGT), 19.4% (5 of 17) progressed (univariate OR, 2.4); however, 60.0% (3 of 5) of participants with G-->A transitions at position 1 of codon 12 (GGT-->AGT) progressed (univariate OR, 8.7; P = 0.004 using chi2 test). (+info)
(4/1094) Apoptotic activity is increased in parallel with the metaplasia-dysplasia-carcinoma sequence of the bronchial epithelium.
A high level of apoptotic activity and an independence of apoptosis from the expression of p53 and bcl-2 have been observed in non-small-cell lung carcinoma. We examined 44 samples of normal, metaplastic and premalignant (i.e. mild, moderate and severe dysplasias and carcinoma in situ) bronchial epithelia to evaluate whether differences in the apoptotic activity could already be seen in the stages preceding squamous cell carcinoma of the lung (SQCLC). Apoptotic cells and bodies were visualized by 3' end labelling. The expression of p53 and members of the bcl-2 gene family, such as bcl-2, bax and mcl-1, were determined immunohistochemically with specific antibodies. The relative number of apoptotic cells and bodies [apoptotic index (AI%)] was already increased threefold as the normal bronchial epithelium changed to squamous metaplasia, and the AIs of the dysplastic lesions were about four times higher than those of the normal epithelium. Apoptosis was significantly associated with cell proliferation, as determined by proliferating cell nuclear antigen (PCNA) immunohistochemistry. However, the extent of apoptosis did not correlate with the expression of p53, bcl-2, bax and mcl-1. We conclude that, in the metaplasia-dysplasia-carcinoma sequence in the lung, the elevation of the AI% is an early event associated with cell proliferation activity, but is independent of the expression of p53, bcl-2, mcl-1 and bax. (+info)
(5/1094) Intestinal metaplasia of human stomach displays distinct patterns of mucin (MUC1, MUC2, MUC5AC, and MUC6) expression.
Intestinal metaplasia is a well-established premalignant condition of the stomach that is characterized by mucin carbohydrate modifications defined by histochemical methods. The purpose of the present study was to see whether the expression of mucin core proteins was modified in the different types of intestinal metaplasia and to evaluate the putative usefulness of mucins as "molecular markers" in this setting. We used a panel of monoclonal antibodies with well-defined specificities to MUC1, MUC2, MUC5AC, and MUC6 to characterize the expression pattern of mucins. In contrast to normal gastric mucosa, the complete form or type I intestinal metaplasia (n = 20) displayed little or no expression of MUC1, MUC5AC, or MUC6 in the metaplastic cells and strong expression of the intestinal mucin MUC2 in the goblet cells of all cases. The incomplete forms of intestinal metaplasia, type II (n = 25) and type III (n = 16), expressed MUC1 and MUC5AC in every case, both in goblet and in columnar cells. MUC6 was also expressed in 16 cases of type II intestinal metaplasia and in 11 cases of type III intestinal metaplasia. The intestinal mucin MUC2 was expressed in every case of incomplete intestinal metaplasia, mostly in goblet cells. The mucin expression profile in the different types of intestinal metaplasia allows the identification of two patterns: one defined by decreased levels of expression of "gastric" mucins (MUC1, MUC5AC, and MUC6) and expression of MUC2 intestinal mucin, which corresponds to type I intestinal metaplasia, and the other defined by coexpression of "gastric mucins" (MUC1, MUC5AC, and MUC6) together with the MUC2 mucin, encompassing types II and III intestinal metaplasia. Our results challenge the classical sequential pathway of intestinal metaplasia (from type I to type III via a type II intermediate step). (+info)
(6/1094) Helicobacter pylori-induced chronic active gastritis, intestinal metaplasia, and gastric ulcer in Mongolian gerbils.
The establishment of persisting Helicobacter pylori infection in laboratory animals has been difficult, but in 1996 Hirayama reported the development of a successful Mongolian gerbil model. The present study was undertaken with two aims: to better characterize the normal histological structure and histochemical properties of the gastric mucosa of the Mongolian gerbil; and to evaluate the progression of the histopathological features of H. pylori-induced gastritis in this animal model for one year after the experimental infection. Seventy-five Mongolian gerbils were used. Mongolian gerbils were sacrificed at 2, 4, 8, 12, 26, 38, and 52 weeks after H. pylori inoculation. Sections prepared from stomachs immediately fixed in Carnoy's solution were stained with hematoxylin and eosin and Alcian blue at pH 2.5/periodic acid-Schiff, a dual staining consisting of the galactose oxidase-cold thionin Schiff reaction and paradoxical Concanavalin A staining, and with immunostaining for H. pylori and BrdU. H. pylori infection induced in the Mongolian gerbil a chronic active gastritis, in which a marked mucosal infiltration of neutrophils on a background of chronic inflammation became detectable 4 weeks after inoculation and continued up to 52 weeks. Intestinal metaplasia and gastric ulcers appeared after 26 weeks in some of the animals, whereas others developed multiple hyperplastic polyps. The Mongolian gerbil represents a novel and useful model for the study of H. pylori-induced chronic active gastritis and may lend itself to the investigation of the epithelial alterations that lead to intestinal metaplasia and gastric neoplasia. (+info)
(7/1094) Pathologic changes induced in respiratory tract mucosa by polycyclic hydrocarbons of differing carcinogenic activity.
Seven aromatic polycyclic hydrocarbons (PCHs) were investigated for their toxic effects on respiratory mucosa: benzo(e)pyrene (BeP), pyrene, anthracene, benz(a)anthracene(BaA), dibenz(a,c)anthracene(DBacA), benzo (a)pyrene (BaP), and dimethylbenz(a)anthracene (DMBA). The compounds were chosen because they comprise a spectrum of PCHs ranging from noncarcinogens, to initiators, to weak and strong carcinogens. All of them except DMBA are environmentally relevant chemicals. The chemicals were tested over an 8-week period. Heterotopic tracheal transplants were continously exposed and the histopathologic effects induced by the various PCHs were periodically assessed semiquantitatively. All PCHs exhibited varying degrees of toxicity for respiratory epithelium and submucosa. BeP clearly showed the least toxicity followed by pyrene and anthracene. BaA and DBacA caused marked epithelial and submucosal changes. In addition to epithelial hyperplasia, undifferentiated epithelium and squamous metaplasia developed. Marked mononuclear infiltration occurred in the subepithelial connective tissue. With BaP the epithelial and submucosal changes were similar but were much stronger. DMBA was the most toxic substance, causing epithelial necrosis followed by generalized keratinizing squamous metaplasia; the subepithelial changes consisted of an early acellular exudate and, later (at 8 weeks), marked condensation and hyalinization of the lamina propria. The toxic response pattern of the tracheal mucosa to carcinogenic agents was characterized by the chronicity of epithelial and connective tissue damage, as opposed to the short-lived hyperplastic and inflammatory response elicited by the noncarcinogens and weak initiators. (+info)
(8/1094) Helicobacter pylori infection enhances glandular stomach carcinogenesis in Mongolian gerbils treated with chemical carcinogens.
Helicobacter pylori (Hp) is thought to be a stomach carcinogen from epidemiological findings. To determine the effects of infection with the bacteria on experimental carcinogenesis, a study of the glandular stomach of Mongolian gerbils (MGs) was performed. Male MGs were treated with N-methyl-N'-nitro-N-nitrosoguanidine followed by inoculation with Hp or infected with Hp followed by N-methyl-N'-nitro-N-nitrosoguanidine administration. Animals were killed at week 50, and their excised stomachs underwent microbiological and histopathological examinations. In addition, a serological investigation was performed. The incidences of adenocarcinomas were significantly higher in animals treated with 60 or 300 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine for 10 weeks followed by Hp inoculation or Hp followed by 20 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine for 30 weeks than in the respective controls. Moreover, tumour-bearing animals had higher titres of anti-Hp antibodies than tumour-free animals. Of interest was the finding that a dose of 100 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine given to infected gerbils eradicated the Hp in about half the animals, with a concomitant reduction in the promoting effect. No tumours were found in animals infected with Hp without N-methyl-N'-nitro-N-nitrosoguanidine or non-treated gerbils. Hp infection enhances glandular stomach carcinogenesis in MGs treated with N-methyl-N'-nitro-N-nitrosoguanidine. Animals with high titres of anti-Hp antibodies are at greatest risk of developing neoplasms. (+info)