title: Combined effect of multiple carcinogens and synergy index.
abstract: Tumorigenesis often involves exposure to multiple carcinogens. We here construct a two-stage model, which consists of individuals in three states:normal, intermediate, and malignant. We considered a population exposed to two carcinogens and examined two exposure scenarios: (1) two carcinogens exposed separately; and (2) carcinogens are exposed simultaneously. We calculate the incidence rate of the malignant state, introducing a "synergy index" to quantify the interaction between the two carcinogens. We confirmed the results of previous analyses, but we also calculate more general situation in which each carcinogen affects both steps.
authors.affiliation: Regulatory Sciences Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage, Chiba 263-8555, Japan. kawag@nirs.go.jp
authors.forename: Isao
authors.initials: I
authors.lastname: Kawaguchi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Doi
authors.forename: Shizuko
authors.initials: S
authors.lastname: Kakinuma
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Shimada
mesh_terms: D002273:Carcinogens / Q000008:administration & dosage / Q000633:toxicity*; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced*; D003043:Cocarcinogenesis; D004357:Drug Synergism; D004781:Environmental Exposure / Q000009:adverse effects; D006801:Humans; D008954:Models, Biological; D009369:Neoplasms / Q000139:chemically induced*
chemical_list: D002273:Carcinogens