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

Ten million new cancer patients are diagnosed each year worldwide. Many specific causes of cancer are known, ranging from factors related to lifestyle, diet and chronic infections to occupational exposures. Primary and secondary prevention continue to be of major importance in cancer control globally. The global burden of cancer, especially the part attributable to infectious diseases, disproportionally affects populations in developing countries. Inadequate access to treatment (pharmaceuticals and other modern technology) plays a role in perpetuating this disparity. Drugs and vaccines may not be accessible because of excessive cost or because development of the required products has been neglected. The remarkable advances in molecular understanding of the carcinogenesis process over the past 25 years have transformed the approaches to cancer control. Promising new tools in preventive oncology, such as immunization (vaccines) and chemoprevention, have emerged. Vaccines are currently being tested in trials e.g., against hepatitis B virus and human papillomaviruses. Chemoprevention has been successfully achieved in animal experiments, and has been validated in several clinical trials. The current agents and strategies should not be regarded as a panacea; more effective and safer vaccines and chemopreventive agents are needed. Future enhanced efforts on an international basis are needed to coordinate the prevention and intervention research efforts in a cost-efficient and affordable manner. Cancer prevention deserves continuing high priority in terms of both research and application, also in the developing countries. New ventures may be built on possible expansion of IARC's role in prevention and intervention research into a "Global Science Force" by following the examples of e.g., the Gambia Hepatitis Intervention Study and the cervix cancer screening trials in India. WHO's support with its regional offices would be beneficial, together with further national funding and support, and research collaboration and funding from more wealthy countries.
Asian Pac J Cancer Prev 2002
PMID:Social Responsibility in Cancer Prevention Research: IARC as a 'Global Science Force' 1271 86

Incidence rates of colorectal cancer are relatively low in Asian populations, in which soy foods are commonly consumed. Soybeans and soy foods are an almost exclusive source of isoflavone intake. In in vitro studies, isoflavones have been shown to have various anticarcinogenic properties such as inhibition of protein tyrosine phosphorylation, induction of apoptosis, antiangiogenesis, and inhibition of DNA topoisomerase. Thus the protective role of soy foods and isoflavones in the etiology of colorectal cancer is a matter of interest. We therefore reviewed animal and epidemiological studies of colorectal cancer in relation to soybeans, soy foods, and isoflavones. Animal studies fairly consistently showed that soyfoods or isoflavones inhibited the formation of aberrant crypt foci, but did not clearly demonstrate an inhibitory effect of soy foods and isoflavones on the development of chemically-induced colorectal cancer. Several case-control studies have suggested that soy food consumption may confer a reduced risk of colorectal cancer although the findings are rather inconsistent. Most of the previous studies, especially in Japan, ascertained only the frequency of consuming selected soy foods, and thus were defective as regards the measurement of the total consumption of soy foods. Further epidemiological studies are needed to clarify the role for soy foods in colorectal carcinogenesis.
Asian Pac J Cancer Prev 2002
PMID:Soybeans, Soy Foods, Isoflavones and Risk of Colorectal Cancer: a Review of Experimental and Epidemiological Data. 1271 90

Modifying effects of chlorogenic acid (CA) on carcinogen-induced large bowel carcinogenesis was examined in rats. A total of 150 male F344 rats, 4 weeks old, were divided into 5 groups. At 6 weeks of age, groups 1-3 were given subcutaneous injections of AOM (15 mg/kg body weight) once a week for three weeks. Group 2 was given the diet mixed with CA at the dose of 250 ppm during the initiation phase (5 weeks), and group 3 was exposed to the same diet during the post-initiation phase (32 weeks). Group 4 received the diet with CA throughout the experiment. Group 5 was maintained on the basal diet alone and served as a control. At the termination of the experiment (36 weeks after the start), the incidence of colon tumors in group 2 and 3 demonstrated a tendency for decrease as compared with group 1 although this did not attain significance At this time, the multiplicity of colon tumors of group 2 was significantly smaller than in group 1. In this study, the anti-proliferating cell nuclear antigen (PCNA) indices for non-neoplastic cells of the colon mucosae in groups 2 and 3 were also smaller than in group 1. The data suggest that CA has chemopreventive potential against colon carcinogenesis in rats like that showen in a hamster model with use of methylazoxymethanol acetate.
Asian Pac J Cancer Prev 2002
PMID:Inhibitory Effects of Chlorogenic Acid on Azoxymethane-induced Colon Carcinogenesis in Male F344 Rats. 1271 96

Tea (Camellia sinensis) is one of the most popular beverages, consumed worldwide. The health promoting properties of tea have been attributed to its antioxidative polyphenolic constituents and their oxidative products. The aim of the present study was to evaluate the chemopreventive efficacy of a black tea infusion on azoxymethane induced colonic preneoplastic lesions, the aberrant crypt foci in Sprague-Dawley rats. Rats were injected with azoxymethane (15mg/kg.b.w.) and received oral administration of 1% and 2% (w/v) tea infusions from the 1(st)day of carcinogen application. The treatment was continued for 12 weeks. The colons were then assessed for aberrant crypt foci and compared with the untreated carcinogen control group. In situ cell proliferation and in situ apoptosis were also estimated using Brdu incorporation and the TUNEL method, respectively. Aberrant crypt foci were reduced significantly (by 44% in the 1% tea-treated and by about 40% in 2% tea-treated group). Significant decrease in proliferation and increase in apoptosis suggest a possible interplay between the two processes resulting in inhibition of colon carcinogenesis by black tea.
Asian Pac J Cancer Prev 2002
PMID:Inhibition of Cell Proliferation and Induction of Apoptosis During Azoxymethane Induced Colon Carcinogenesis by Black Tea. 1271 7

In addition to mutagens and/or carcinogens a number of modulators of carcinogenesis are present in our environment. Some of them are contained in our regular foods and therefore dietary factors play a role in the development of some types of cancers including colon cancer. Epidemiological studies have suggested that a diet rich in fruits and vegetables is associated with reduced risk for a number of common cancers. There are still many unknown constituents and/or factors in foods that could either enhance or reduce the possibility of developing cancer. Animal studies of experimental chemical carcinogenesis have indicated that several non-nutritive components in foods, belonging to different chemical groups, protect against certain types of cancers including colonic neoplasms. These chemicals are known as "chemopreventive agents". Many of them are antioxidants and might suppress carcinogenesis through: (I) inhibiting Phase I enzymes; (ii) induction of Phase II enzymes; (iii) scavenging DNA reactive agents; (iv) suppression of hyper-cell proliferation induced by carcinogens; and/or (v) inhibition of certain properties of neoplastic cells. With the continuing increase in the incidence of colon cancer, there is an ever increasing need to determine the most effective means for prevention and to understand the underlying mechanism(s). Previous studies in our laboratory demonstrated protective effects of several naturally occurring products against rat colon tumorigenesis. This article will introduce our recent studies in our search for chemopreventive effects of flavonoids (diosmin and hesperidin) and other phytochemicals in edible plants on rat colon carcinogenesis.
Asian Pac J Cancer Prev 2001
PMID:Chemoprevention of Colon Carcinogenesis by Dietary Non-nutritive Compounds. 1271 27

The anticarcinogenic effect of tomato juice, a natural source of antioxidants and other chemopreventive / antimutagenic agents, was studied in a skin carcinogenesis model in mice. The possible mode of action was also investigated. Oral administration of tomato juice afforded protection from development of skin tumour and increased life expectancy which may be attributed to the combined action of a number of chemical compounds with cancer chemopreventive properties present in tomato. The protective role may be associated with a decreased level of lipid peroxides noted in the tomato treated group and modulation of host detoxification enzymes. Exposure to the carcinogen resulted in a depression of the liver enzymes- glutathione-S-transferase (GST), glutathione peroxidase (GPx) and superoxide dismutase (SOD). Oral administration of tomato juice resulted in significant activation of all these enzymes (p<0.001). These results suggest a preventive role of tomato juice during carcinogenesis which is mediated possibly by their modulatory effects on biotransformation enzymes and the detoxification system of the host.
Asian Pac J Cancer Prev 2001
PMID:Protective Effects of Tomato Juice on Mouse Skin Carcinogenesis. 1271 53

Cyclooxygenase 2 (COX2) is an inducible enzyme synthesizing prostaglandins from arachidonic acid, which is thought to play an important role in colorectal carcinogenesis. Since the COX2 polymorphisms, if functional, may modify the carcinogenesis pathway, the associations between the reported polymorphisms and colorectal cancer risk were examined in a hospital-based case-control study. Six polymorphisms of the gene encoding COX2 were genotyped for 241 non-cancer individuals (controls) and 148 colorectal cancer patients (74 colon cancer, 73 rectal cancer, and 1 colorectal cancer date, 22 polymorphisms including the above six have been reported for COX2. The other polymorphisms remain to be examined.
Asian Pac J Cancer Prev 2001
PMID:Genotype Frequencies of Cyclooxygenease 2 (COX2) Rare Polymorphisms for Japanese with and without Colorectal Cancer. 1271 55

The protective role of two commonly consumed natural dietary items- bitter gourd and tomato against endogenous as well as 7,12- dimethylbenz(a)anthracene (DMBA) induced lipid peroxidation in the livers of mice was investigated. The rationale for such an approach is that lipid peroxidation has been suggested to play a key role in human cancer development. There was a sharp rise in lipid peroxidation (measured as thiobarbituric acid reactive substances formation) during skin carcinogenesis induced by DMBA in mice. Aqueous extracts of bitter gourd and tomato juice were found to be very potent inhibitors of lipid peroxidation both in normal and DMBA treated mice. Our observations support the hypothesis that natural combinations of phytochemicals present in the fruit juices exert cancer-protective effects via a decrease in lipid peroxidation.
Asian Pac J Cancer Prev 2000
PMID:Oral Consumption of Bitter Gourd and Tomato Prevents Lipid Peroxidation in Liver Associated with DMBA Induced Skin Carcinogenesis in Mice. 1271 65

The dietary effect of monoglucosyl-rutin (M-R), a flavonoid, on azoxymethane (AOM)-induced colon carcinogenesis was investigated in two experiments with 5 week old, F344 male rats. In the first experiment (5 weeks study), effects of MR on AOM (15 mg/kg body weight 3 times weekly)-induced formation of aberrant crypt foci (ACF) in five groups were assessed. In this experiment, group 3 given 500 ppm M-R with AOM had a significantly smaller number of ACF containing 4 or more aberrant crypts than group 1 with AOM alone, and groups 2 and 3 given 100 ppm or 500 ppm M-R respectively had significantly lower BrdU labeling indices in the epithelial cells of large bowel than group 1. For the second experiment, rats were divided into 8 groups. Groups 1-5 were given AOM as in the first experiment. Groups 2-5 were fed diets containing 100ppm or 500ppm M-R for 4 weeks in the initiation phase or 36 weeks in the post-initiation phase. Group 6 was given 500ppm M-R throughout the experiment, and group 7 was kept on the basal diet and served as a control. At the termination of the experiment (40 weeks after the start), groups 2-5 had significantly smaller numbers of positive cells with anti-proliferating cell nuclea antigen (PCNA) antibody than group 1. Furthermore, group 5 treated with 500ppm M-R for 36 weeks demonstrated tendencies for decrease in the incidence and multiplicity of colon tumors. These data suggest that M-R has the potential to inhibit AOM-induced colon carcinogenesis.
Asian Pac J Cancer Prev 2000
PMID:Inhibitory Effects of Dietary Monoglucosyl-rutin on Azoxymethane-induced Colon Carcinogenesis in Rats. 1271 67

Chemoprevention with food phytochemicals is currently regarded as one of the most attractive strategies for cancer control. We have been continuously working on the identification and characterization of chemopreventive phytochemicals extracted from a diverse range of edible plants. Recently, we have utilized a convenient assay, the tumor promoter-induced superoxide generation test, with differentiated HL-60 cells for primary screening, and performed chemical studies of antioxidative food phytochemicals. Here, we report our criteria for evaluation of new types of chemopreventors on the basis of the involvement of leukocyte-derived reactive oxygen in carcinogenesis.
Asian Pac J Cancer Prev 2000
PMID:Search for Naturally-occurring Antioxidative Chemopreventors on the Basis of the Involvement of Leukocyte-derived Reactive Oxygen Species in Carcinogenesis. 1271 77


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