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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epstein-Barr virus (EBV) involvement in gastric carcinoma has been demonstrated by the presence of EBV genomes and EBV-encoded small RNA (EBER) in the carcinoma cells, monoclonal proliferation of EBV-infected carcinoma cells and elevated antibody titers. The present study was conducted to investigate the prevalence of EBV involvement among gastric carcinomas observed in nine Japanese cities with varying gastric cancer rates. In situ hybridization of EBER-1 was applied to paraffin sections from 1848 carcinomas observed in 1795 cases and EBV involvement was detected based on uniform hybridization in carcinoma cells. Epstein-Barr virus was detected in 6.6% of lesions and 6.7% of cases. The rate of EBV involvement did not vary significantly for each city and there was no correlation with underlying gastric cancer mortality rates. Thus, geographic variation of gastric cancer rates within Japan cannot be explained in terms of EBV involvement. Epstein-Barr virus-related gastric carcinoma is one of the most common EBV-related tumors in Japan. The involvement of EBV was significantly more frequent among males than among females, mainly for cancers occurring in the upper and middle part of the stomach, and exhibited more variation by cell type among males. These observations suggest that other factors yet to be discovered may modulate the causal role of EBV in gastric carcinogenesis.
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PMID:Epstein-Barr virus related gastric cancer in Japan: a molecular patho-epidemiological study. 829 45

To elucidate the possible role of Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC), we investigated the EBV genome in NPC by in situ DNA hybridization using radioisotope- and and biotin-labeled EBV DNA probes. The EBV genome was detected in the tumor cells in all (100%) 60 cases, irrespective of histological type, but not in the lymphocytes. Silver grains, which reflected the copy number of the EBV genome, were more abundant in the nonkeratinizing, spindle cell, and undifferentiated carcinomas than in keratinizing squamous cell carcinoma. In the keratinizing carcinoma, which was poorly differentiated in this series, the EBV genome was usually detected in anaplastic tumor cells, and not in the keratinizing areas. The sensitivity of the radioisotopic technique was superior to that of the biotinylated probe method (100 vs. 81.7%, p < 0.0003). These results suggest that EBV is etiologically related to nasopharyngeal carcinogenesis and that the differentiation of tumor cells in vivo, and probably also in vitro, may become incompatible with EBV replication.
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PMID:Detection of Epstein-Barr virus genome in nasopharyngeal carcinoma by in situ DNA hybridization. 829 87

Most nasopharyngeal carcinomas (NPCs) are of the nonkeratinizing or undifferentiated types, which are consistently associated with Epstein-Barr virus (EBV). The smaller group of highly differentiated, keratinizing NPCs seems to be only infrequently associated with EBV. In order to examine whether these rare tumors were related to another oncogenic virus, the authors used the polymerase chain reaction to examine paraffin-embedded sections of 15 keratinizing NPCs for human papillomavirus (HPV) types 6, 11, 16, and 18 genomic sequences. HPV DNA was found in 4 tumors (1 HPV-11-positive, and 3 HPV-16-positive tumors). None of 23 undifferentiated or nonkeratinizing NPCs harbored HPV DNA. The putatively oncogenic HPV type 16 may thus be involved in the carcinogenesis of some EBV-negative keratinizing squamous cell nasopharyngeal carcinomas.
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PMID:Human papillomavirus types 11 and 16 detected in nasopharyngeal carcinomas by the polymerase chain reaction. 829 66

As a part of screening studies for chemopreventive agents (anti-tumor-promoters), six North American plants belonging to the Amorpha genus were tested using an in vitro assay system. Of these plants, Amorpha fruticosa exhibited strong inhibitory effects on Epstein-Barr virus early antigen (EBA-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Also six rotenoids, amorphispironone [1], tephrosin [2], amorphigenin [3], 12a-hydroxyamorphigenin [4], 12a-hydroxydalpanol [5], and 6'-O-D-glucopyranosyldalpanol [6], were isolated from the leaves of A. fruticosa. Among these retenoids, 1 and 2 exhibited remarkable inhibitory effects of EBV-EA activation induced by TPA. Further, 1 and 2 exhibited significant anti-tumor-promotion effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These investigations suggested that these rotenoids might be valuable anti-tumor-promoters.
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PMID:Studies on inhibitors of skin tumor promotion, XII. Rotenoids from Amorpha fruticosa. 835 86

Dihydroagarofuran sesquiterpenes, which were isolated from Tripterygium wilfordii Hook fil. var. regelii Makino and Euonymus sieboldianus Blume, showed inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Triptogelin A-1, one of the active dihydroagarofuran sesquiterpenes, exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. Interestingly, triptogelin A-1 was more effective when applied after TPA-treatment (post-treatment) than before TPA-treatment (pretreatment). The findings indicate that these dihydroagarofuran sesquiterpenes might be valuable antitumor promoters.
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PMID:Inhibitory effects of triptogelin A-1 on 12-O-tetradecanoylphorbol-13- acetate-induced skin tumor promotion. 838

Fanconi's anemia (FA) cells are highly susceptible to both reactive oxygen species and mitomycin C (MMC), a DNA cross-linking agent. In this study we have determined the amounts of 8-hydroxydeoxyguanosine (8OHdG), typical of oxidative DNA damage, in Epstein-Barr virus transformed lymphoblasts from FA patients and normal controls by the use of HPLC combined with electrochemical detection. FA cells (HSC72 and 99 cells being assigned to FA complementation group A) formed 2-3 times more 8OHdG than control cells after incubation with 20 mM H2O2 at 37 degrees C for 30 min. FA cells also formed more 8-hydroxyguanosine, typical of oxidative RNA damage, than control cells. FA cells showed decreased activity to decompose H2O2. Although the activity in FA cells was only 20-30% less than control cells, the remaining, undecomposed H2O2 concentration was almost twice as much in FA cells as in control cells, and the remaining H2O2 concentration correlated well with the amounts of 8OHdG formation. The H2O2 decomposing activity was almost completely inhibited by sodium azide (NaN3) or aminotriazole, both catalase inhibitors. With these inhibitors the amounts of 8OHdG formation were much higher than in those cells without inhibitors, and were almost the same in control cells as in FA cells. Catalase activity in FA cell lysates was 70-80% of controls. MMC also increased 8OHdG formation in FA cells only at ED100 but not at ED50. These results indicate that FA cells, at least FA complementation group A cells, have increased susceptibility to oxidative DNA damage, and that this increased susceptibility is possibly due to decreased catalase activity. These results also suggest that catalase plays an important role in protecting DNA from oxidative damage. However, this increased susceptibility to oxidative DNA damage is considered not to be the major cause of the increased susceptibility to MMC.
Carcinogenesis 1993 Jun
PMID:Increased formation of 8-hydroxydeoxyguanosine, an oxidative DNA damage, in lymphoblasts from Fanconi's anemia patients due to possible catalase deficiency. 838 71

As a part of screening studies for cancer chemopreventive agents (anti-tumor promoters) 33 Dryopteris phlorophenone derivatives have been evaluated. The compounds tested comprised of monomeric acylphloroglucinols (e.g. desaspidinol, aspidinol) as well as dimeric (e.g. aspidin, desaspidin), trimeric (e.g. filixic acids), and tetrameric (e.g. dryocrassin) phlorophenone, wherein hexacyclic rings are bound together by a methylene bridge. These compounds were examined for their in vitro anti-tumor promoting effect on Epstein-Barr virus antigen activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). The two dimeric compounds aspidin and desaspidin, which were found to be the most active among the tested phlorophenones, were also examined in vivo on two stage mouse skin carcinogenesis, and found to show significant inhibitory effect on 7,12-dimethylbenz[alpha]anthracene (DMBA)-TPA tumor promotion.
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PMID:Anti-tumor promoting activity of Dryopteris phlorophenone derivatives. 869 39

Although most lung carcinomas and mesotheliomas are associated with well-known risk factors, these cancers develop in only a minority of persons exposed to known risk factors. On the other hand, these cancers develop in some patients without exposure to known risk factors. This indicates that other environmental factors play a role in the carcinogenesis of these tumors. Oncogenic viruses such as Epstein-Barr virus (EBC) are well-established agents in the development of certain cancers. EBV genomes have been detected by in situ hybridization in gastric adenocarcinomas and in nasopharyngeal carcinomas. To determine whether EBV infection is associated with pulmonary adenocarcinoma or mesothelioma, we performed EBV-encoded RNA-1 in situ hybridization on 80 pulmonary adenocarcinoma and 50 mesothelioma resection specimens. Sections were cut from paraffin-embedded tissue and EBV-encoded RNA-1 in situ hybridization was performed using an antisense oligoprobe. Sections were reviewed for the presence of EBV-encoded RNA-1 in tumor cells. All 80 adenocarcinomas and 50 mesotheliomas were negative for EBV-encoded RNA-1 by in situ hybridization. In conclusion, no evidence for an etiologic role for EBV in the development of pulmonary adenocarcinoma or pleural mesothelioma was found in this study.
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PMID:Absence of evidence for an etiologic role for Epstein-Barr virus in neoplasms of the lung and pleura. 873 63

To search for possible anti-tumor-promoters (cancer chemopreventive agents), we carried out primary screening of 23 triterpenoid hydrocarbons (1-23) isolated from ferns using an in vitro synergistic assay system. Of these triterpenoids, hop-17(21)-ene (2), neohop-13(18)-ene (3), neohop-12-ene (4), taraxerane (17), multiflor-9(11)-ene (18), multiflor-8-ene (19), glutin-5(10)-ene (21) and taraxastane (23) exhibited remarkable inhibitory effects on Epstein-Barr virus (EBV) activation induced by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA). Further, compounds 2 and 3 exhibited remarkable anti-tumorpromoting effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test using 7,12-dimethybenz[a]anthracene (DMBA) as an initiator and TPA as a promoter.
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PMID:Anti-tumor-promoting activities of triterpenoids from ferns. I. 883 70

In this report, we describe a case with triple tiny cancers of the stomach developing adjacent to each other and resected endoscopically in a single mucosal piece. The three cancers differed from each other histologically. The surrounding mucosa was atrophic pyloric gland mucosa with moderate to severe intestinal metaplasia. Both histological and serological examinations were negative for Helicobacter pylori. Each of the three cancer lesions was positive for mutant p53 product immunohistochemically. None of the cancers were positive for Epstein-Barr virus sequence in an in situ hybridization analysis. These lesions suggest that certain local conditions in the gastric mucosa can result in carcinogenesis of different histological types of gastric cancers.
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PMID:Three histologically different tiny gastric cancers developing adjacent to each other, resected endoscopically in a single mucosal piece. 885 48


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