Viral hepatitis in all its forms is a major public health problem throughout the world, affecting several hundreds of millions of people. Viral hepatitis is a cause of considerable morbidity and mortality both from acute infection and chronic sequelae which include, in the case of hepatitis B, C and D, chronic active hepatitis and cirrhosis. Hepatocellular carcinoma, which is one of the 10 commonest cancers worldwide, is closely associated with hepatitis B and, at least in some regions of the world, with hepatitis C virus. This timely monograph is a distillation of knowledge of hepatitis B, C and D, based on a review of 1000 studies by a small group of scientists. (It is interesting to note in passing that some 5000 papers on viral hepatitis are published annually in the world literature.) The epidemiological, clinical and experimental data on the association between infection with hepatitis B virus and primary liver cancer in humans are reviewed in a readable and succinct format. The available information on hepatitis C and progression to chronic infection is also evaluated and it is concluded (perhaps a little prematurely) that hepatitis C virus is carcinogenic. However, it is concluded that hepatitis D virus, an unusual virus with a number of similarities to certain plant viral satellites and viroids, cannot be classified as a human carcinogen. There are some minor criticisms: there are few illustrations and some complex tabulations (for example, Table 6) and no subject index. A cumulative cross index to IARC Monographs is of little value and occupies nearly 30 pages. This small volume is a useful addition to the overwhelming literature on viral hepatitis, and the presentation is similar to the excellent World Health Organisation Technical Reports series on the subject published in the past. It is strongly recommended as a readable up-to-date summary of a complex subject; and at a cost of 65 Sw.fr (approximately £34) is excellent value. A J ZUCKERMAN

https://jcp.bmj.com/content/jclinpath/48/7/691.1.full.pdf

IARC Monographs on the Evaluation of Carcinogenic Risks to Humans

For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from...

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Hormones and endocrine-disrupting chemicals: Low-dose effects and nonmonotonic dose responses

Estimated number of new cancer cases for 2010, excluding basal and squamous cell skin cancers and in situ carcinomas except urinary bladder. Note: State estimates are offered as a rough guide and should be interpreted with caution. State estimates may not add to US total due to rounding.

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Cancer Facts & Figures 2004

The complexity of tobacco smoke leads to some confusion about the mechanisms by which it causes lung cancer. Among the multiple components of tobacco smoke, 20 carcinogens convincingly cause lung tumors in laboratory animals or humans and are, therefore, likely to be involved in lung cancer induction. Of these, polycyclic aromatic hydrocarbons and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone are likely to play major roles. This review focuses on carcinogens in tobacco smoke as a means of simplifying and clarifying the relevant information that provides a mechanistic framework linking nicotine addiction with lung cancer through exposure to such compounds. Included is a discussion of the mechanisms by which tobacco smoke carcinogens interact with DNA and cause genetic changes--mechanisms that are reasonably well understood--and the less well defined relationship between exposure to specific tobacco smoke carcinogens and mutations in oncogenes and tumor suppressor genes. Molecular epidemiologic studies of gene-carcinogen interactions and lung cancer--an approach that has not yet reached its full potential--are also discussed, as are inhalation studies of tobacco smoke in laboratory animals and the potential role of free radicals and oxidative damage in tobacco-associated carcinogenesis. By focusing in this review on several important carcinogens in tobacco smoke, the complexities in understanding tobacco-induced cancer can be reduced, and new approaches for lung cancer prevention can be envisioned.

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Tobacco Smoke Carcinogens and Lung Cancer

https://bura.brunel.ac.uk/bitstream/2438/18351/1/FullText.pdf

An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling.

Discovered in the early 1800s, the use of cadmium and various cadmium salts started to become industrially important near the close of the 19th century, rapidly thereafter began to flourish, yet has diminished more recently. Most cadmium used in the United States is a byproduct from the smelting of zinc, lead, or copper ores, and is used to manufacture batteries. Carcinogenic activity of cadmium was discovered first in animals and only subsequently in humans. Cadmium and cadmium compounds have been classified as known human carcinogens by the International Agency for Research on Cancer and the National Toxicology Program based on epidemiologic studies showing a causal association with lung cancer, and possibly prostate cancer, and studies in experimental animals, demonstrating that cadmium causes tumors at multiple tissue sites, by various routes of exposure, and in several species and strains. Epidemiologic studies published since these evaluations suggest that cadmium is also associated with cancers of the breast, kidney, pancreas, and urinary bladder. The basic metal cationic portion of cadmium is responsible for both toxic and carcinogenic activity, and the mechanism of carcinogenicity appears to be multifactorial. Available information about the carcinogenicity of cadmium and cadmium compounds is reviewed, evaluated, and discussed.

Cadmium-induced Cancers in Animals and in Humans

This paper considers the use of historical control data in the evaluation of tumor incidences from carcinogenicity studies in rodents. Although the most appropriate control group for interpretative purposes is always the concurrent control, there are instances in which the use of historical control information can aid an investigator in the overall evaluation of tumor incidence data. One example is rare tumors; another is a tumor that shows a marginally significant result relative to concurrent controls. However, before historical control data can be used in a formal testing framework, a number of important issues must first be considered. The nomenclature conventions and diagnostic criteria for each study should be identical to insure unambiguous identification of all relevant tumors in the historical control database. Criteria should be established that will aid in determining whether a particular study should be included in the database. This will assure a homogeneous set of studies upon which to base statistical comparisons. Since study-to-study variability in tumor rates may exceed what would be expected by chance alone, these sources of variability should be identified and controlled. Finally, statistical procedures should be employed that adjust for extra-binomial variability. This paper also summarizes tumor incidence data from untreated Fischer 344 rats and B6C3F1 mice in the National Toxicology Program (NTP) historical control database. All studies in the database are of two years duration, and all neoplasms occurring with a frequency of 0.5% or more are reported.

https://journals.sagepub.com/doi/pdf/10.1177/019262338401200203

Use of historical control data in carcinogenicity studies in rodents.

Groups of 50 male and 50 female B6C3F1 mice were exposed 6 hours per day, 5 days per week, for 60 to 61 weeks to air containing 0, 625, or 1250 parts per million 1,3-butadiene. These concentrations are somewhat below and slightly above the Occupational Safety and Health Administration standard of 1000 parts per million for butadiene. The study was designed for 104-week exposures but had to be ended early due to cancer-related mortality in both sexes at both exposure concentrations. There were early induction and significantly increased incidences of hemangiosarcomas of the heart, malignant lymphomas, alveolar-bronchiolar neoplasms, squamous cell neoplasms of the forestomach in males and females and acinar cell carcinomas of the mammary gland, granulosa cell neoplasms of the ovary, and hepatocellular neoplasms in females. Current workplace standards for exposure to butadiene should be reexamined in view of these findings.

Multiple organ carcinogenicity of 1,3-butadiene in B6C3F1 mice after 60 weeks of inhalation exposure

The carcinogenicity of inhaled 1,3-butadiene was evaluated in C57BL/6 x C3H F1 mice exposed to concentrations of this gas ranging from 6.25 to 625 ppm. Butadiene is a high production volume chemical, used mainly in the manufacture of synthetic rubber. In these 2-yr inhalation studies, a potent multisite carcinogenic response was observed, including neoplasms of the lung at concentrations as low as 6.25 ppm. Early occurrence and extensive development of lethal lymphocytic lymphomas in mice exposed to 625 ppm of butadiene reduced the number of animals at risk for the expression of later developing neoplasms at other sites; at lower exposure concentrations, dose responses were demonstrated for hemangiosarcomas of the heart and neoplasms of the lung, forestomach, Harderian gland, preputial gland, liver, mammary gland, and ovary. So far, no long-term studies on butadiene have been conducted at exposure concentrations that have not shown a carcinogenic response. In separate experiments with reduced exposure durations, butadiene induced neoplastic responses at multiple organ sites even after only 13 wk of exposure. Because of the correspondence between these animal data and recent epidemiology findings, there is a worldwide public health need to reevaluate current workplace exposure standards for 1,3-butadiene.

https://cancerres.aacrjournals.org/content/canres/50/20/6592.full.pdf

Carcinogenicity of 1,3-Butadiene in C57BL/6 × C3H F1 Mice at Low Exposure Concentrations

Groups of 50 male and female Fischer 344 rats and male and female B6C3Fl mice were fed diets containing 6000 or 12,000 (rats) or 3000 or 6000 (mice) mg di(2‐ethylhexyl) phthalate (DEHP)/kg feed for 103 consecutive wk. Concurrent controls (50 of each sex and species) were fed diet without the addition of DEHP. Treatment with DEHP did not affect survival rates for rats or mice, nor did it alter the amount of food consumed. Mean body weight gains of treated male rats (6000 and 12,000 mg/kg), female rats (12,000 mg/kg), and female mice (3000 and 6000 mg/kg) were less than those of the corresponding controls. Seminiferous tubular degeneration and hypertrophy of cells in the anterior pituitary were observed in male rats at 12,000 mg/kg, and chronic inflammation of the kidney and seminiferous tubular degeneration were observed in male mice at 6000 mg/kg. Neither clinical signs of toxicity nor nonneoplastic lesions were detected in the other treated groups at incidences greater than in the corresponding controls....

James Huff

Papers

Cadmium-induced Cancers in Animals and in Humans

Use of historical control data in carcinogenicity studies in rodents.

Multiple organ carcinogenicity of 1,3-butadiene in B6C3F1 mice after 60 weeks of inhalation exposure

Carcinogenicity of 1,3-Butadiene in C57BL/6 × C3H F1 Mice at Low Exposure Concentrations

The carcinogenicity of dietary di(2-ethylhexyl) phthalate (DEHP) in Fischer 344 rats and B6C3F1 mice.