Cancer slope factor

Chronic toxicity Mammalian systems Carcinogenicity Neurotoxicity De ve 1 opm e nta l/rep rod u cti ve toxicity Aquatic vertebrates and invertebrates Plants Mutagenicity, increased tumours Reproduction and growth Cancer slope factors Reference doses, and so on IC50, EC50... 

EPA Carcinogenic classification Cancer slope factor oral i nhalati on... 

Verified inhalation and oral slope factors were unavailable from U.S. EPA for dimethylhydrazine. A cancer assessment based upon the carcinogenic potential (withdrawn cancer slope factors) of dimethylhydrazine revealed that AEGL values for a theoretical excess lifetime 10 4 carcinogenic risk exceeded the AEGL-2 values that were based on noncancer endpoints. Because the risk for dimethylhydrazine exposure was estimated from nonverified sources and because AEGLs are applicable to rare events or single once-in-a-lifetime expo... 

No studies were located regarding cancer incidence in animals after inhalation exposure to hexachloroethane. EPA has derived an inhalation unit risk (cancer slope factor) of 1.4x102 (mg/kg/day) 1 for hexachloroethane (IRIS 1995). This inhalation unit risk was calculated using data from oral studies (see Section 2.2.2.8) and Figure 2-2. 

Table 8.5 Selected potencies, or cancer slope factors, used by the US EPAd For those based on animal data, the potencies include a factor for interspecies scaling (see text)...

The linearized multistage model (used by the EPA). This determines the cancer slope factor, which can be used to predict cancer risk at a specific dose. It assumes a linear extrapolation to a zero-dose threshold (Fig. 2.10). This factor is an estimate (expressed in mg/kg/day) of the probability that an individual will develop cancer if exposed to the chemical for 70 years. 

For carcinogens, the risk is expressed in terms of increased risk of developing a cancer (e.g., 1 in 106). This is calculated from the cancer slope factor and the 70-year average daily intake in mg/kg/day. 

Number of chemicals sampled by CDC in third national report 25 Number of chemicals for which EPA reference values (i.e., RfCs or RfDs) and/or cancer slope factors are established ... 

Cancer slope factors are upper bounds, approximating a 95% confidence limit, on the increased cancer risk posed by a lifetime exposure to a carcinogen (EPA 2006). 

Lack of health-based values for comparison Few health-based values (such as RfDs, RfCs, cancer slope factors, or BEIs) are available to put biomonitoring results into context... 

Mixture of concern. Mixture assessments based on data on the mixture of concern include direct testing of the environmental mixture itself or its concentrate, or evaluating fractions or single components of the whole mixture. When occupational, epidemiological, or bioassay data are available on the mixture of concern, a toxicological reference value, such as a reference dose (RfD),1 reference concentration (RfC),2 or cancer slope factor,3 can be determined for the whole mixture using similar... 

Assessment of Human Health Mixture RfD/RfC Hazard Quotient Hazard Index Dose-Response Modeling Cancer Slope Factors Epidemiological Measures Comparative Potency... 

The key risk assessment parameter derived from the EPA carcinogen risk assessment is the cancer slope factor, which is a toxicity value that quantitatively defines the relationship between dose and response. The cancer slope factor is a plausible upper-bound estimate of the probability that an individual will develop cancer if exposed to a chemical for a lifetime of 70 years. The cancer slope factor is expressed as mg/kg/day. See Figure 9.33. 

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