Risk, cancer and manmade chemicals

1/30/2005 Bruce Ames and Lois Swirsky Gold "Cancer Prevention and the Environmental Chemical Distraction" This is an edited version of a chapter titled 'Cancer Prevention and the Environmental Chemical Distraction', by Bruce Ames and Lois Swirsky Gold, in Politicizing Science: the Alchemy of Policymaking, Michael Gough ed., Hoover Institute Press, Stanford, California (2003). Blaming synthetic chemicals for a 'cancer epidemic' is flawed science that makes for dubious policy. Entering a new millennium seems a good time to challenge some old ideas about cancer cause and prevention, which in our view are implausible, have little supportive evidence, and might best be left behind. In this essay, we summarise data and conclusions from 15 years of work, raising five issues that involve toxicology, nutrition, public health, and US government regulatory policy: 1. There is no cancer epidemic other than that due to smoking. 2. The dose makes the poison. Half of all chemicals tested, whether natural or synthetic, cause cancer in high-dose rodent cancer tests. Evidence suggests that this high rate is due primarily to effects that are unique to high doses. The results of these high-dose tests have been used to regulate low-dose human exposures, but are not likely to be relevant. 3. Even Rachel Carson was made of chemicals: natural v synthetic chemicals. Human exposure to naturally occurring rodent carcinogens is ubiquitous and dwarfs the exposure of the general public to synthetic rodent carcinogens. 4. Errors of omission. The major causes of cancer (other than smoking) do not involve exposures [...]

2009-03-25T19:55:04-07:00January, 2005|Archive|

Researcher says HPV vaccine may be a year away

1/30/2005 www.advocate.com Diane Harper, a researcher at Norris Cotton Cancer Center in Lebanon, N.H., has studied the link between human papillomavirus infection and cervical cancer for 20 years. Harper now believes she may have found a vaccine that protects against the two strains of HPV that are linked to 70% of cervical cancers. The vaccine, made by GlaxoSmithKline, was tested from 2000 to 2003 on 1,113 women ages 15 to 25 from the United States, Canada, and Brazil. In women who received three injections and follow-up testing, the vaccine was 100% effective. In those who received only one or two injections, the vaccine proved to be 91% effective. The vaccine offers protection for three to five years. No side effects, except for pain or redness at the injection site, were reported, said Harper, who added that she is an independent researcher and is not paid by GlaxoSmithKline. "It offers such an advantage for women and such a change in health care, one that we will actually see in the next five years," Harper said of the vaccine. If approved by the Food and Drug Administration, it could be available early next year. "I'm extremely excited about the possibilities." According to preliminary findings, said Harper, the vaccine may protect against HPV-associated diseases such as anal cancer, vaginal cancer, vulvular cancer, esophageal cancer, abnormal Pap smears, and mouth or oral cancer. "It's going to take us 20 to 30 years to get the data, but we're really hopeful this has long-term protective [...]

2009-03-25T19:54:25-07:00January, 2005|Archive|

Alcohol Listed as ‘Known Carcinogen’

1/30/2005 U.S. Dept. of Health & Human Services: Report on Carcinogens, 9th edition For the first time alcoholic beverages have been listed as a known human carcinogen by the U.S. Department of Health and Human Services in its "Report on Carcinogens" 9th edition. The report states that consumption of alcoholic beverages is causally related to cancers of the mouth pharynx larynx and esophagus and that studies indicate that the risk is most pronounced among smokers and at the highest levels of consumption. The effect of a given level of alcoholic beverage intake on cancers of the head and neck is influenced by other factors, especially smoking, but that smoking does not explain the increased cancer hazard associated with alcoholic beverage consumption according to the report. There is evidence that suggests a link between alcoholic beverage consumption and cancer of the liver and breast. Potential Hazard The report was first ordered by Congress in 1978 to educate both the public and health professionals in the recognition that many cancers are apparently induced by chemicals in the home workplace general environment and from the use of certain drugs. It identifies "potential" cancer hazards. A listing in the report does not by itself establish that a substance presents a cancer risk to an individual in daily life, according to press releases. However the "known" category is reserved for those substances for which there is sufficient evidence of carcinogenicity from studies in humans that indicates a cause and effect relationship between the exposure and [...]

2009-03-25T19:53:56-07:00January, 2005|Archive|

Lugol’s Dye Spray Chromoendoscopy Establishes Early Diagnosis of Esophageal Cancer in Patients with Primary Head and Neck Cancer

1/27/2005 CL Hashimoto et al. Am J Gastroenterol, February 1, 2005; 100(2): 275-82 Objective: Patients with primary head and neck cancer show a predisposition to develop esophageal cancer. The aim of this study was to investigate in these patients: the prevalence of esophageal cancer comparing the value of chromoendoscopy using Lugol's solution examination to standard endoscopy, in the early diagnosis of esophageal cancer. Methods: Prospective observational study at a state general university hospital in Sao Paulo, Brazil. 326 consecutive adult patients with primary head and neck cancer were evaluated. A standard endoscopy was performed, followed by a 2% lugol's dye spray chromoendoscopy and histopathologic study. The prevalence of esophageal cancer was defined. The results of the two endoscopic methods were compared. Results: Twenty-four patients with esophageal cancer and high-grade intraepithelial neoplasia were detected and had a prevalence of 7.36%. Chromoendoscopy and standard endoscopy were equivalent to the diagnosis of advanced and invasive esophageal cancer. However, standard endoscopy diagnosed 55% of high-grade intraepithelial neoplasia, in comparison to chromoendoscopy that detected 100%. Conclusions: Patients with primary head and neck cancer should be considered as high risks for the presence of esophageal cancer. Lugol's dye chromoendoscopy diagnosed high-grade intraepithelial neoplasia, which went unnoticed with standard endoscopy. It permits a more exact detection of lesion boundaries and facilitates a more precise targeting of biopsy fragments. Authors: CL Hashimoto, K Iriya, ER Baba, T Navarro-Rodriguez, MC Zerbini, JN Eisig, R Barbuti, D Chinzon, and JP Moraes-Filho Authors' affiliation: Department of Gastroenterology, Faculty of Medicine, University [...]

2009-03-25T19:53:25-07:00January, 2005|Archive|

Molecular profiling of tumor progression in head and neck cancer

1/27/2005 TJ Belbin et al. Arch Otolaryngol Head Neck Surg, January 1, 2005; 131(1): 10-8 Objective: To assess gene expression changes associated with tumor progression in patients with squamous cell carcinoma of the oral cavity. Design: A microarray containing 17 840 complementary DNA clones was used to measure gene expression changes associated with tumor progression in 9 patients with squamous cell carcinoma of the oral cavity. Samples were taken for analysis from the primary tumor, nodal metastasis, and "normal" mucosa from the patients' oral cavity. Setting: Tertiary care facility.Patients Nine patients with stage III or stage IV untreated oral cavity squamous cell carcinoma. RESULTS: Our analysis to categorize genes based on their expression patterns has identified 140 genes that consistently increased in expression during progression from normal tissue to invasive tumor and subsequently to metastatic node (in at least 4 of the 9 cases studied). A similar list of 94 genes has been identified that decreased in expression during tumor progression and metastasis. We validated this gene discovery approach by selecting moesin (a member of the ezrin/radixin/moesin [ERM] family of cytoskeletal proteins) and one of the genes that consistently increased in expression during tumor progression for subsequent immunohistochemical analysis using a head and neck squamous cell carcinoma tissue array. Conclusion: A distinct pattern of gene expression, with progressive up- or down-regulation of expression, is found during the progression from histologically normal tissue to primary carcinoma and to nodal metastasis. Authors: TJ Belbin, B Singh, RV Smith, ND Socci, VB Wreesmann, [...]

2009-03-25T19:52:56-07:00January, 2005|Archive|

Psychosocial effects in long-term head and neck cancer survivors

1/27/2005 Richard L Holloway et al. Head Neck, January 24, 2005 Background: To identify and rate the importance of several psychosocial and physiologic influences on quality of life (QOL) among a cohort of 5-year head and neck cancer survivors, we conducted a cross-sectional study of a convenience sample that used both questionnaires and physiologic evaluations. Methods: QOL was assessed by the Functional Assessment of Cancer Therapy (FACT) and the FACT Head and Neck additional concerns (FACT-H&N) questionnaires. Psychosocial characteristics (or risk factors) potentially influencing QOL were measured by the Millon Behavioral Health Inventory (MBHI) and the Social Support Questionnaire (SSQSR). Physiologic risk factors were measured in examinations that included shoulder and neck range of motion, whole and stimulated saliva measurements, and oropharyngeal swallowing efficiency. We evaluated the association of selected QOL measures with three groups of potential risk factors: psychosocial factors, consisting of selected MBHI and SSQSR scales; physiologic factors, consisting of selected physical ability measures; and a combination of psychosocial/physiologic factors. Results: The entire study population of 105 subjects completed the FACT and FACT-H&N questionnaires; 86 of these completed the physiologic tests as well. Combined psychosocial/physiologic models best predicted all QOL measures considered. Psychosocial models alone, compared with physiologic models alone, better predicted FACT physical and social/family well-being measures. Physiologic models alone, compared with psychosocial models alone, better predicted FACT-H&N additional concerns measures. Premorbid pessimism (MBHI) was consistently the best predictor of QOL measures. Conclusions: Both psychosocial and physiologic factors influence QOL in patients with head and neck cancer, [...]

2009-03-25T19:52:05-07:00January, 2005|Archive|

Radiation Sensitizers: A Selective Review of Molecules Targeting DNA and Non-DNA Targets

1/27/2005 Larry K. Kvols, MD Society of Nuclear Medicine Jan 2005 as reported by RedNova.com The ideal radiation sensitizer would reach the tumor in adequate concentrations and act selectively in the tumor compared with normal tissue. It would have predictable pharmacokinetics for timing with radiation treatment and could be administered with every radiation treatment. The ideal radiation sensitizer would have minimal toxicity itself and minimal or manageable enhancement of radiation toxicity. The ideal radiation sensitizer does not exist today. This review outlines the concept of combining 2 modalities of cancer treatment, radiation and drug therapy, to provide enhanced tumor cell kill in the treatment of human malignancies and discusses molecules that target DNA and non-DNA targets. Combining drugs that have unique mechanisms of action and absence of overlapping toxicities with systemically administered radiotherapy should be exploited in future clinical trials. This is an exciting time in clinical oncology research, because we have a plethora of new molecules to evaluate. Surgery, radiation, and chemotherapy have been the mainstays of treatment for human malignancies for more than 40 years. The use of a combination of radiation and chemotherapy is often called chemoradiation in the medical literature. For most of the last 4 decades, this has involved the use of cytotoxic agents with external beam radiation. Recently, however, with newer molecules that target very specific pathophysiology or molecular pathways and the use of radiation delivered systemically by antibodies or hormones labeled with radionuclides, the concept of radiation sensitizers has been expanded. Heidlberger's preclinical [...]

2009-03-25T19:51:33-07:00January, 2005|Archive|

The Level of Evidence for Permitting a Qualified Health Claim: FDA’s Review of the Evidence for Selenium and Cancer and Vitamin E and Heart Disease1

1/26/2005 Paula R. Trumbo The American Society for Nutritional Sciences J. Nutr. 135:354-356, February 2005 Health claims are authorized for the labeling of foods when there is significant scientific agreement among qualified experts on the evidence for a relationship between a food or food component (substance) and a disease. Qualified health claims are permitted when there is less scientific evidence for a substance-disease relationship, therefore requiring qualifying language. The evidence for a relationship between vitamin E and heart disease and selenium and cancer was reviewed by the U.S. FDA. It was determined that there was insufficient evidence to permit a qualified health claim for vitamin E and cancer, whereas there was some evidence for permitting a qualified health claim for selenium and cancer. Author's affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740

2009-03-25T19:50:56-07:00January, 2005|Archive|

The predictive value of p53, p53R2, and p21 for the effect of chemoradiation therapy on oesophageal squamous cell carcinoma

1/26/2005 H Okumura et al. British Journal of Cancer (2005) 92, 284-289. The p53 family regulates cell-cycle arrest, triggers apoptosis or is involved in repair of DNA damage. In the present study, we analysed the expression of some p53 family proteins and their responses to chemoradiation therapy (CRT) in cases of oesophageal squamous cell carcinoma (ESCC). We immunohistochemically investigated the relationship between p53, p53R2, and p21 expression in biopsy specimens of untreated primary tumours and their clinical and histological responses to CRT in 62 patients with ESCC. Chemoradiation therapy consisted of 5-fluorouracil plus cisplatin and 40 Gy of radiation. The rates of clinical and histological responses (complete or partial) to CRT were 71.0% (clinical) and 52.8% (histological). The rate of positive expression was 43.5% for p53, 37.1% for p53R2, and 54.8% for p21 expression. Statistically significant correlations were found between p53 or p53R2 expression and favourable response to CRT (P=0.0001 or 0.041 clinical, P=0.016 or 0.0018 histological, respectively). Furthermore, in p53-negative tumours, CRT was more effective in tumours with p53R2 negative expression than those with p53R2 positive expression (P=0.0014). We demonstrated that the negative expression of p53 and p53R2 expression was closely related to the effect of CRT and should predict the CRT outcome in patients with ESCC. Authors: H Okumura1, S Natsugoe1, M Matsumoto1, Y Mataki1, H Takatori1, S Ishigami1, S Takao1 and T Aikou1 Authors' Affiliations: 1Department of Surgical Oncology, Digestive Surgery, Graduate School of Medicine, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima 890-8520, Japan

2009-03-25T19:49:44-07:00January, 2005|Archive|

Current Evidence and Research Needs to Support a Health Claim for Selenium and Cancer Prevention

1/26/2005 Gerald F. Combs, Jr The American Society for Nutritional Sciences J. Nutr. 135:343-347, February 2005 Selenium was recognized as a nutritional essential only in the late 1950s. That it might also be anticarcinogenic was first suggested a decade later based on ecological relationships of cancer mortality rates and forage crop Se contents in the United States. Since that time, a substantial body of scientific evidence indicated that Se can, indeed, play a role in cancer prevention. This is supported by a remarkably consistent body of findings from studies with animal tumor and cell culture models, and by some, but not all epidemiologic observations. The body of clinical trial data is less extensive, yet also supportive. The consistent findings from this evidence are that both inorganic and organic Se-compounds can be antitumorigenic at doses greater than those required to support the maximal expression of the selenoenzymes that are generally regarded as discharging the nutritional effects of the element. Although the plausibility of Se as a cancer-protective factor is clear, other research is required to support evidence-based evaluation of this hypothesis. In addition to further, well-planned clinical trials, that research must include the development of analytical tools for speciating Se in foods and biological tissues; the development of better means of assessing Se status in ways that are relevant to cancer prevention; and the determination of the minimal dose of Se that is both safe and effective in reducing cancer risk.

2009-03-25T19:03:55-07:00January, 2005|Archive|
Go to Top