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Query: UMLS:C0006826 (cancer)
 1,092,456 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tocopherol, a well known tissue anti-oxidant, given before local X-ray irradiation of 2 transplantable rat tumours was previously found to increase significantly the effect of irradiation. In the present study tocopherol did not influence the development of tumour necroses during growth of a transplantable rat hepatoma. The tumour tissue oxygenation of a transplantable rat sarcoma was neither found to be influenced by tocopherol. This suggests that an enhanced tumour radio-sensitivity by tocopherol is probably not explained by an influence on tumour cell oxygenation.
Cancer Lett 1978 Oct
PMID:Influence of tocopherol on tumour cell oxygenation. 68

Alpha-Tocopherol (vitamin E) protects against free radical damage, which has been implicated in aging, cancer initiation, and atherosclerosis. We have found that physiological concentrations of alpha-tocopherol specifically inhibited aorta smooth muscle cell (VSMC, line A7r5) proliferation and protein kinase C (PKC) activity. Other water and lipid soluble antioxidants were inactive. alpha-Tocopherol inhibition of PKC and of VSMC proliferation may represent a physiological mechanism, relevant to the onset of diseased states such as atherosclerosis.
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PMID:Alpha-tocopherol (vitamin E) regulates vascular smooth muscle cell proliferation and protein kinase C activity. 189 54

The effects of DL-alpha-tocopherol and DL-alpha-tocopherol succinate on neuroblastoma N1E 115 cells were studied. Tocopherol had no growth-arresting properties, whereas its succinate ester derivative inhibited growth at concentrations greater than or equal to 20 microM. The succinate derivative was taken up somewhat more readily than free tocopherol; however, for any equal uptake of both forms of vitamin E, only the succinate derivative could affect growth. Tocopherol succinate was taken up without marked conversion to tocopherol. Following uptake, plasma membrane and organelle fractions contained most of the vitamin E derivatives; however, the particulate and membrane fractions were about twice as enriched in the succinate derivative as in free tocopherol. On the other hand, a proportionally higher amount of unconjugated vitamin E was recovered in the cytosol fraction. Fluorescence polarization studies indicated no differences in the overall fluidity of the plasma membranes treated or not treated with either form of vitamin E. The data point to the functionality of the free carboxyl group of the succinate derivative as a basis for the difference in potency of the two forms of vitamin E.
Nutr Cancer 1989
PMID:Studies on the effects of vitamin E on neuroblastoma N1E 115. 271 Jun 49

The Alpha-Tocopherol Beta-Carotene (ATBC) Cancer Prevention Study was a placebo-controlled, randomized intervention trial testing the hypothesis that beta-carotene and alpha-tocopherol (vitamin E) supplements prevent lung and other cancers. The study is predicated on a substantial body of evidence supporting a role in cancer prevention for these micronutrients. Based on the 2 x 2 factorial study design, 29,133 eligible male cigarette smokers aged 50-69 y were randomly assigned to receive beta-carotene (20 mg), alpha-tocopherol (50 mg), beta-carotene and alpha-tocopherol, or placebo daily for 5-8 y. Capsule compliance was high (median = 99%). beta-Carotene treatment did not result in a decrease in cancer at any of the major sites but rather in an increase at several sites, most notably lung, prostate, and stomach (number of cases 474 compared with 402, 138 compared with 112, and 70 compared with 56, respectively). The vitamin E group had fewer incident cancers of the prostate and colorectum compared with the group not receiving vitamin E (number of cases 99 compared with 151 and 68 compared with 81, respectively), but more cancers of the stomach (70 compared with 56). In contrast to these intervention-based findings for beta-carotene and vitamin E supplements, we observed lower lung cancer rates in men with higher amounts of both serum and dietary beta-carotene and vitamin E at baseline.
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PMID:Effects of alpha-tocopherol and beta-carotene supplements on cancer incidence in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study. 749 43

Evidence is accumulating that folate, a B vitamin found in green leafy vegetables, may affect the development of neoplasia. We examined the relationship between folate status and colorectal cancer in a case-control study nested within the Alpha-Tocopherol Beta-Carotene Study cohort of male smokers 50-69 years old. Serum folate was measured in 144 incident cases (91 colon, 53 rectum) and 276 controls matched to cases on baseline age, clinic, and time of blood collection. Baseline dietary folate was available from a food-use questionnaire for 386 of these men (92%). Conditional logistic regression modeling was used. No statistically significant association was observed between serum folate and colon or rectal cancer. Although a 2-fold increase in rectal cancer risk was suggested for men with serum folate > 2.9 ng/ml and those in the highest quartile of energy-adjusted folate intake, there was no evidence of a monotonic dose-response, and all confidence intervals included unity. For dietary folate and colon cancer, odds ratios of 0.40 [95% confidence interval (CI), 0.16-0.96], 0.34 (95% CI, 0.13-0.88), and 0.51 (95% CI, 0.20-1.31) were obtained for the second through fourth quartiles of energy-adjusted folate intake, respectively, compared to the first (P for trend = 0.15). Furthermore, men with a high-alcohol, low-folate, low-protein diet were at higher risk for colon cancer than men who consumed a low-alcohol, high-folate, high-protein diet (OR, 4.79; 95% CI, 1.36-16.93). This study suggests a possible association between low folate intake and increased risk of colon cancer (but not rectal cancer) and highlights the need for further studies that measure dietary folate and methionine, along with biochemical measures of folate (i.e., erythrocyte and serum), homocysteine, and vitamin B12.
Cancer Epidemiol Biomarkers Prev 1996 Jul
PMID:Colorectal cancer and folate status: a nested case-control study among male smokers. 882 51

Final proof for the anticarcinogenic effect of any agent can best be obtained from a controlled trial in a sufficiently large population at risk of cancer. Interpretation of the results from such a trial may be difficult, particularly if the results are only marginally significant or negative, or if they are in conflict with epidemiological data or studies in laboratory animals. This article discusses difficulties in the evaluation of clinical trial findings, using the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study (the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Group, 1994) as an example. Special attention is paid to problems associated with trial design, properties of the study population, time of intervention, and selection of the dose of the putative anticarcinogenic agent. Potential sources of bias are discussed. The advantages and disadvantages of a single large trial versus several small or medium-sized trials are examined.
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PMID:Evaluation of human trial findings. 892 37

Epidemiological evidence suggests that airway obstruction is an independent risk factor for lung cancer and that this cannot be explained by active or passive smoking alone. Chlamydia pneumoniae infection has been associated with chronic bronchitis and its exacerbates. Our aim was to evaluate the association between chronic C. pneumoniae infection and risk of lung cancer among male smokers. Smoking males with lung cancer (n = 230) and their age- and locality-matched controls were selected among participants of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The presence of C. pneumoniae infection was assessed by analyzing specific antibodies and immune complexes in 2 serum samples collected with a 3-year interval before the lung cancer diagnosis. The diagnosis of chronic infection was based on stable levels of positive specific IgA antibody (titer > or = 16) and immune complex (titer > or = 4). Relative risks were estimated by odds ratios (OR) adjusted for age, locality and smoking history by a conditional logistic regression model. Markers suggesting chronic C. pneumoniae infection were present in 52% of cases and 45% of controls and hence were positively associated with the incidence of lung cancer (OR 1.6; 95% confidence interval [CI] 1.0-2.3). The incidence was especially increased in men younger than 60 years (OR 2.9; 95% CI 1.5-5.4) but not in the older age group (OR 0.9; 95% CI 0.5-1.6). Before concluding that C. pneumoniae infection is a new independent risk factor for lung cancer, corroboration from other studies with larger number of cases and longer follow-up is needed.
Int J Cancer 1997 Feb 20
PMID:Serological evidence of an association between Chlamydia pneumoniae infection and lung cancer. 903 66

We validated diagnoses of acute myocardial infarction (AMI) and death from coronary heart disease (CHD) found in the Finnish National Hospital Discharge Register and the Register of Causes of Death from a sample of the 29,133 men participating in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The cases were traced to hospitals and institutes performing medico-legal death cause examinations and all relevant information was collected. The cardiac events were re-evaluated according to the diagnostic criteria of the Finnish contribution to the WHO MONICA project, i.e. the FINMONICA criteria. Altogether 408 cases of non-fatal AMI (n = 217) and death from CHD (n = 191) were reviewed. In the re-evaluation 94% of them (95% confidence interval 92-96%) were diagnosed as either definite (57%) or possible (37%) AMI. Non-fatal cases were more often classified definite AMI in the review, whereas fatal cases were more often classified possible AMI. Age or trial supplementation group did not affect classification, and no secular trend was observed. In conclusion, the diagnoses of AMI and death from CHD in the registers were highly predictive of a true major coronary event defined by strict criteria, thus their use in endpoint assessment in epidemiological studies and clinical trials is justified.
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PMID:Validity of diagnoses of major coronary events in national registers of hospital diagnoses and deaths in Finland. 908 94

The relation of intakes of specific fatty acids and the risk of coronary heart disease was examined in a cohort of 21,930 smoking men aged 50-69 years who were initially free of diagnosed cardiovascular disease. All men participated in the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and completed a detailed and validated dietary questionnaire at baseline. After 6.1 years of follow-up from 1985-1988, the authors documented 1,399 major coronary events and 635 coronary deaths. After controlling for age, supplement group, several coronary risk factors, total energy, and fiber intake, the authors observed a significant positive association between the intake of trans-fatty acids and the risk of coronary death. For men in the top quintile of trans-fatty acid intake (median = 6.2 g/day), the multivariate relative risk of coronary death was 1.39 (95% confidence interval (CI) 1.09-1.78) (p for trend = 0.004) as compared with men in the lowest quintile of intake (median = 1.3 g/day). The intake of omega-3 fatty acids from fish was also directly related to the risk of coronary death in the multivariate model adjusting also for trans-saturated and cis-monounsaturated fatty acids (relative risk (RR) = 1.30, 95% CI 1.01-1.67) (p for trend = 0.06 for men in the highest quintile of intake compared with the lowest). There was no association between intakes of saturated or cis-monounsaturated fatty acids, linoleic or linolenic acid, or dietary cholesterol and the risk of coronary deaths. All the associations were similar but somewhat weaker for all major coronary events.
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PMID:Intake of fatty acids and risk of coronary heart disease in a cohort of Finnish men. The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. 914 59

The high incidence of hepatocellular carcinoma (HCC) in cirrhosis, where previous studies have indicated a severe reduction in several antioxidant vitamin factors, prompted us to compare plasma liposoluble vitamins with tocopherol content in healthy and neoplastic liver tissue in humans. This, with a view to a more positive preventive dietary approach, given the conflicting results obtained by liposoluble vitamin dietary supplementation in different malignancies. Eleven patients with cirrhosis, 18 patients affected by cirrhosis with HCC, and 10 patients with liver metastases (LM) from digestive tract adenocarcinomas were compared with controls who had undergone perlaparoscopic cholecistectomy. Plasma alpha- and beta-carotene, retinol and tocopherol, together with liver tocopherol, from both nonmalignant portions and malignant nodules of the same organ, were determined by high-performance liquid chromatography following a well-assessed technique. The results confirm a trend towards a reduction in circulating carotenoids and tocopherol in cirrhosis and in patients affected by cirrhosis with HCC. Tocopherol content in liver tissue is significantly decreased in cirrhosis (0.26 + 0.03 micromol/g prot., mean + SEM, P < .001) and in cirrhotic areas of the HCC group (0.31 + 0.02, P < .002), with respect to its content in liver specimens of healthy controls (0.46 + 0.03) and in healthy areas of the same organ in patients with LM (0.41 + 0.03). Tocopherol concentration is further reduced by 50% in malignant liver nodules of HCC, with respect to surrounding cirrhotic tissue, whereas in metastatic liver nodules from digestive neoplasms the tocopherol content is almost twice that of healthy surrounding areas. This unpredictable tocopherol behavior in liver specimens, of secondary as opposed to primary malignancies of the liver, affords further insight into the conflicting effects of liposoluble vitamins employed in the chemopreventive treatment of different malignant diseases, where hepatic tocopherol concentration show opposite trends: halved in primary HCC and doubled in LM of digestive adenocarcinomas, with respect to healthy controls.
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PMID:Hepatic tocopherol content in primary hepatocellular carcinoma and liver metastases. 921 53


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