Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Over the past 20 years, several epidemiological studies have found an association between exposure to electromagnetic fields (EMFs) and health effects, including childhood leukemia and adult brain cancer. However, experts strongly disagree about whether this association is causal and, if so, how strong it is. In this article, we examine several alternatives to reduce EMFs from sources of the California power grid, including undergrounding distribution and transmission lines and reconfiguring or rephasing lines. The alternatives were evaluated in terms of the potential health risk reduction, cost, impacts on service reliability, property values, and many other consequences. Because of the uncertainty about an EMF-health link, the main effort was to determine the sensitivity of the decisions to the probability and seriousness of an EMF hazard. User-friendly computer models were developed to allow stakeholders to change the model assumptions and parameters to analyze the impacts of their own assumptions and estimates on the decision. The analysis clearly demonstrated that only four of the many concerns raised by the stakeholders could make a difference in the decision: health risks, costs, service reliability, and property values. Whether undergrounding, moderate alternatives for EMF reduction, or no change was the best decision depended on a few key factors, including the probability that EMF exposure is a hazard, the severity of this hazard, how the EMF reduction measures are financed, and the impacts on property values. While the analysis did not resolve the EMF issues, it showed that even in the most controversial settings, a little analysis goes a long way to clarifying the issues and to focus the debate.
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PMID:Managing potential health risks from electric powerlines: a decision analysis caught in controversy. 1566 Jun 6

Two major transcripts of lymphoid enhancer factor-1 (LEF-1) have been described. The long isoform with b-catenin binding domain functions as a transcriptional enhancer factor. The short isoform derives from an intronic promoter and exhibits dominant negative activity. Recently, alterations of LEF-1 isoforms distribution have been described in colon cancer. In the current study we employed a quantitative real-time reverse transcription PCR method (TaqMan) to analyze expression of LEF-1 isoforms in a large cohort of human tumor (n = 304) and tumor-free control samples (n = 56). The highest expression level of LEF-1 was found in carcinoma samples whereas brain cancer samples expressed little. Expression of LEF-1 was different in distinct cancer types. For example, the mRNA level of LEF-1 was lower in testicular tumor samples compared with tumor-free control samples. Besides epithelial cancers, significant LEF-1 expression was also found in hematopoietic cells. In hematological malignancies, overall LEF-1 level was higher in lymphocytic leukemias compared with myeloid leukemias and normal hematopoiesis. However, acute myeloid leukemia and acute lymphocytic leukemia showed a significantly increased fraction of the oncogenic LEF-1 compared with chronic lymphocytic leukemia and chronic myeloid leukemia. Taken together, these data suggest that LEF-1 is abundantly expressed in human tumors and the ratio of the oncogenic and the dominant negative short isoform altered not only in carcinomas but also in leukemia.
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PMID:Alterations of lymphoid enhancer factor-1 isoform expression in solid tumors and acute leukemias. 1575 19

Electrical power lines are ubiquitous in the developed world and in urban areas of the developing world. All electrical currents, including those running through power lines, generate electric and magnetic fields (EMFs). Electrical power lines, towers,and distribution poles are used by birds for perching, hunting, and nesting. Therefore, many bird species, like humans, are exposed to EMFs throughout their lives. EMFs have been implicated in adversely affecting multiple facets of human health,including increasing the risks of life-threatening illnesses such as leukemia, brain cancer, amyotrophic lateral sclerosis, clinical depression, suicide, and Alzheimer's disease. A great deal of research and controversy exists as to whether or not exposure to EMFs affects the cellular, endocrine, immune, and reproductive systems of vertebrates. Laboratory work has used mice, rats, and chickens as models for this EMF research in an effort to understand better the possible implications of EMF exposure for humans. However, EMF exposure of wild birds may also provide insight into the impacts of EMFs on human health. This review focuses on research examining the effects of EMFs on birds; most studies indicate that EMF exposure of birds generally changes, but not always consistently in effect or in direction, their behavior, reproductive success, growth and development, physiology and endocrinology, and oxidative stress under EMF conditions. Some of this work has involved birds under aviary conditions, while other research has focused on free-ranging birds exposed to EMFs. Finally, a number of future research directions are discussed that may help to provide a better understanding of EMF effects on vertebrate health and conservation.
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PMID:The effects of electromagnetic fields from power lines on avian reproductive biology and physiology: a review. 1580 52

Results of various studies have indicated a potential association between exposures to electrical and/or magnetic fields and risks of various cancers. The authors used a cross-sectional ecological study design to investigate such a potential association. In areas proximate to 42 amplitude modulated (AM) radio transmitters, 11 high-power study sites (i.e., areas exposed to 100-1500-kW transmission power) and 31 low-power study sites (i.e., areas exposed to 50-kW transmission power) were identified. The incidence of cancer within a 2-km radius of each transmitter was obtained from (a) Korean medical-insurance data for the years 1993 through 1996, (b) population census data for the year 1995, and (c) resident registration data for the year 1995. The authors calculated age-standardized rate ratios for total cancer, leukemia, malignant lymphoma, brain cancer, and breast cancer, and compared the incidence of cancer within 2 km of the high-power transmitters vs. the incidence within 2 km of the low-power transmitters. Four control areas for each high-power transmitter were also selected. The control areas were located in the same, or nearest adjacent, province as the high-power sites, but were at least 2 km from any of the transmitters. Indirect standardized observed/expected ratios for the high-power sites vs. control areas were calculated for each transmitter separately, and for 4 transmitter groupings defined by power level (i.e., 100 kW, 250 kW, 500 kW, and 1500 kW). The authors found no significant increase in age-standardized rate ratios of cancers for high-power vs. low-power sites, with the exceptions of total cancer and of brain cancer in women. Among the 11 high-power sites, there were significantly increased incidences of leukemia in 2 areas and of brain cancer in 1 area. Future studies should incorporate additional detailed exposure assessments and a strong analytical study design to explore the possible association between radiofrequency radiation from AM radio transmitters and cancer.
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PMID:Incidence of cancer in the vicinity of Korean AM radio transmitters. 1585 10

Activity of thymidine kinase 1 in serum (STK) is a useful marker for leukaemia and lymphoma, but not for solid tumors. We investigate thymidine kinase 1 concentration in serum (S-TK1) as a potential tumor marker. S-TK1 concentration and STK activity levels were determined in 9 human malignant diseases (breast, gastric, rectal, colorectal, lung, brain cancer, hepatoma, lymphoma, leukaemia) and in benign and non-cancerous diseases, representing 850 preoperative cases. Healthy volunteers (n=43) were used as positive controls. S-TK1 concentration was determined by ECL dot blot assay and STK activity levels by an RIA assay. S-TK1 concentrations and STK activity levels in preoperative malignant patients were significantly higher than in healthy individuals, in patients with benign tumors and in those with non-cancerous diseases. Significant correlations between concentration and activity level were only found in healthy individuals, in patients with benign tumors, and in some patients with malignancies, i.e. leukaemia, and breast and gastric cancers. About 90-95 percent of the malignant patients showed S-TK1 concentrations above those of the healthy controls. The corresponding value for STK activity was about 75 percent. When sera from malignant patients were diluted with sera from healthy individuals, S-TK1 concentrations and STK activity levels decreased more than expected. This indicates the presence of a compound (or compounds) in the serum of healthy individuals that destabilises S-TK1. We conclude that S-TK1 concentration is a more sensitive tumor marker in solid malignancies than is STK activity.
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PMID:Concentration of thymidine kinase 1 in serum (S-TK1) is a more sensitive proliferation marker in human solid tumors than its activity. 1614 66

Glioblastoma multiforme is an aggressive form of brain cancer that responds poorly to chemotherapy and is generally incurable. The basis for the poor response of this cancer to chemotherapy is not well understood. The atypical protein kinases C (PKCiota and PKCzeta) have previously been implicated in leukaemia cell chemoresistance. To assess the role of atypical PKC in glioblastoma cell chemoresistance, RNA interference was used to deplete human glioblastoma cells of PKCiota. Transfection of cells with either of two different RNA duplexes specific for PKCiota caused a partial sensitisation to cell death induced by the chemotherapy agent cisplatin. To screen for possible mechanisms for PKCiota-mediated chemoresistance, microarray analysis of gene expression was performed on RNA from glioblastoma cells that were either untreated or depleted of PKCiota. This identified sets of genes that were regulated either positively or negatively by PKCiota. Within the set of genes that were negatively regulated by PKCiota, the function of the gene coding for GMFbeta, an enhancer of p38 mitogen-activated protein kinase (MAP kinase) signaling, was investigated further, as the p38 MAP kinase pathway has been previously identified as a key mediator of cisplatin cytotoxicity. The expression of both GMFbeta mRNA and protein increased upon PKCiota depletion, and this was accompanied by an increase in cisplatin-activated p38 MAP kinase signaling. Transient overexpression of GMFbeta increased cisplatin-activated p38 MAP kinase signaling and also sensitised cells to cisplatin cytotoxicity. The increase in cisplatin cytotoxicity seen with PKCiota depletion was blocked by the p38 MAP kinase inhibitor SKF86002. These data show that PKCiota can confer partial resistance to cisplatin in glioblastoma cells by suppressing GMFbeta-mediated enhancement of p38 MAP kinase signaling.
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PMID:Protection of glioblastoma cells from cisplatin cytotoxicity via protein kinase Ciota-mediated attenuation of p38 MAP kinase signaling. 1633 Dec 46

Two cohorts of Chernobyl cleanup workers from Estonia (4,786 men) and Latvia (5,546 men) were followed from 1986 to 1998 to investigate cancer incidence among persons exposed to ionizing radiation from the Chernobyl accident. Each cohort was identified from various independent sources and followed using nationwide population and mortality registries. Cancers were ascertained by linkage with nationwide cancer registries. Overall, 75 incident cancers were identified in the Estonian cohort and 80 in the Latvian cohort. The combined-cohort standardized incidence ratio (SIR) for all cancers was 1.15 (95% confidence interval (CI) = 0.98-1.34) and for leukemia, 1.53 (95% CI = 0.62-3.17; n = 7). Statistically significant excess cases of thyroid (SIR = 7.06, 95% CI = 2.84-14.55; n = 7) and brain cancer (SIR = 2.14, 95% CI = 1.07-3.83; n = 11) were found, mainly based on Latvian data. However, there was no evidence of a dose response for any of these sites, and the relationship to radiation exposure remains to be established. Excess of thyroid cancer cases observed may have been due to screening, the leukemia cases included 2 unconfirmed diagnoses, and the excess cases of brain tumors may have been a chance finding. There was an indication of increased risk associated with early entry to the Chernobyl area and late follow-up, though not statistically significant. Further follow-up of Chernobyl cleanup workers is warranted to clarify the possible health effects of radiation exposure.
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PMID:Cancer risk among Chernobyl cleanup workers in Estonia and Latvia, 1986-1998. 1643 38

Leukemia and brain cancer patients under age 15 years, along with controls with respiratory illnesses who were matched to cases on age, sex, and year of diagnosis (1993-1999), were selected from 14 South Korean hospitals using the South Korean Medical Insurance Data System. Diagnoses were confirmed through the South Korean National Cancer Registry. Residential addresses were obtained from medical records. A newly developed prediction program incorporating a geographic information system that was modified by the results of actual measurements was used to estimate radio-frequency radiation (RFR) exposure from 31 amplitude modulation (AM) radio transmitters with a power of 20 kW or more. A total of 1,928 leukemia patients, 956 brain cancer patients, and 3,082 controls were analyzed. Cancer risks were estimated using conditional logistic regression adjusted for residential area, socioeconomic status, and community population density. The odds ratio for all types of leukemia was 2.15 (95% confidence interval (CI): 1.00, 4.67) among children who resided within 2 km of the nearest AM radio transmitter as compared with those resided more than 20 km from it. For total RFR exposure from all transmitters, odds ratios for lymphocytic leukemia were 1.39 (95% CI: 1.04, 1.86) and 1.59 (95% CI: 1.19, 2.11) for children in the second and third quartiles, respectively, versus the lowest quartile. Brain cancer and infantile cancer were not associated with AM RFR.
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PMID:Radio-frequency radiation exposure from AM radio transmitters and childhood leukemia and brain cancer. 1831 58

Using the fixed-effect model, the author quantitatively estimated the risks of cancers of the colon, bladder, kidneys, and brain as well as non-Hodgkin's lymphoma and leukemia among firefighters. The risk of these six cancers was not markedly elevated when cohort mortality studies were considered. When all mortality studies were considered, however, there was a mild increase in risk for kidney cancer and non-Hodgkin's lymphoma, with a summary relative risk (sumRR) of 1.22 (95% confidence interval [CI] = 1.02-1.43) and 1.40 (95% CI = 1.20-1.60), respectively. A subcohort analysis based on duration of employment revealed that firefighters with 30 or more years of employment had a significantly increased mortality risk for colon cancer, sumRR of 1.51 (95% CI = 1.05-2.11); kidney cancer, sumRR of 6.25 (95% CI = 1.70-16.00); brain cancer, sumRR of 2.53 (95% CI = 1.27 7.07); and leukemia, sumRR of 2.87 (95% CI = 1.43-5.14). After firefighters had 40 or more years of employment, their risk of mortality was significantly increased for colon cancer, sumRR of 4.71 (95% CI = 2.03-9.27); kidney cancer, sumRR of 36.12 (95% CI = 4.03-120.42); and bladder cancer, sumRR of 5.7 (95% CI = 1.56-14.63). The risk for non-Hodgkin's lymphoma was elevated but not significantly so among firefighters with 20 or more years of employment, with sumRR of 1.72 (95% CI = 0.90-3.31). Kidney cancer risk was significantly elevated as early as the second decade of employment.
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PMID:Risk of cancer among firefighters: a quantitative review of selected malignancies. 1789 91

The identification, purification, and characterization of cancer stem cells holds tremendous promise for improving the treatment of cancer. Mounting evidence is demonstrating that only certain tumor cells (i.e. the cancer stem cells) can give rise to tumors when injected and that these purified cell populations generate heterogeneous tumors. While the cell of origin is still not determined definitively, specific molecular markers for populations containing these cancer stem cells have been found for leukemia, brain cancer, and breast cancer, among others. Systems approaches, particularly molecular profiling, have proven to be of great utility for cancer diagnosis and characterization. These approaches also hold significant promise for identifying distinctive properties of the cancer stem cells, and progress is already being made.
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PMID:Systems biology and cancer stem cells. 1803


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