Comments on Extrapolation of Cancer Response from High Dose to Low Dose

Comments on extrapolation of cancer response from high dose to low dose.

In making judgments as to the cancer risk from low level exposure to carcinogens it is generally necessary to base these judgments on high dose or high incidence data from laboratory or epidemiological studies. The biological considerations involved in making such extrapolations are discussed, as well as some of the mathematical procedures. The difficulties presented by moving from species to s...

High- to low-dose extrapolation: critical determinants involved in the dose response of carcinogenic substances.

Recent investigations on mechanism of carcinogenesis have demonstrated important quantitative relationships between the induction of neoplasia, the molecular dose of promutagenic DNA adducts and their efficiency for causing base-pair mismatch, and the extent of cell proliferation in target organ. These factors are involved in the multistage process of carcinogenesis, including initiation, promo...

Problems of extrapolation from high dose to low dose in Tradescantia mutation studies.

Inflorescences of several clones of Tradescantia heterozygous for flower color have been treated with ionizing radiation and with the gaseous form of several known or suspected chemical mutagens. Pink somatic mutations were subsequently scored in the stamen hair cells of mature flowers and exposure/dose response curves were constructed. Results indicate clearly that there is no threshold for mu...

Low-dose extrapolation of radiation-related cancer risk.

Biological bases for cancer dose-response extrapolation procedures.

The Moolgavkar-Knudson theory of carcinogenesis of 1981 incorporates the viable portions of earlier multistage theories and provides the basis for both the linearized multistage and biologically based dose-response extrapolation methodologies. This theory begins with the premise that cancer occurs because irreversible genetic changes (mutations) are required for transformation of normal cells t...