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Percentage of chemicals classified as carcinogens.

Low dose Carcinogenesis Low dose Anticarcinogenesis Hormesis can be seen in the same animal species Richard Wilson, Harvard University Frank Pompei, Exergen Amherst, MA Tuesday, June 11th 2002.

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Percentage of chemicals classified as carcinogens.

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  1. Low dose CarcinogenesisLow dose AnticarcinogenesisHormesiscan be seen in the same animal speciesRichard Wilson, Harvard UniversityFrank Pompei, ExergenAmherst, MA Tuesday, June 11th 2002

  2. Regulatory posture for 30 yearsIf an increase in tumors in any site is seen after administration of a chemical,label it carcinogenic and ban it.This has led experimentation e.g. NTP

  3. Choose most sensitive gender/speciesIgnore anticarcinogenic effectsAllow ad-libitum feeding(simpler and “more sensitive” )

  4. Sir Richard Peto and others;if the cancer is identical to one that occurs naturally, adding a small dose is (differentially) linear (Taylor’s theorem)But what do data say?

  5. It has long been known that alcohol consumption displays hormetic effects (reduction in mortality at low doses and increase in high doses)This is attributed to addition of two effects:reduction in incidence of strokeincrease in cancer (and antisocial behavior)

  6. Percentage of chemicals classified as carcinogens.

  7. Percentage of chemicals classified as anticarcinogens

  8. About 5% of cases show anticarcinogenic responses in one site and carcinogenic responses in another.They add to what is seen in alcohol

  9. Carcinogenic responses are easiest to see when there is an increase in rare tumorsAnticarcinogenic responses can only be seen as a reduction in common tumors.The sum will display hormesis even if each is individually linear with dose

  10. Schematic picture showing how this leads to hormesis

  11. Kociba’s data on dioxin

  12. Slide of well knowndata on bladder and on liver

  13. Megamouse data

  14. Science only progresses by (however tentatively) believing dataDo we believe the lowest doese data on Dioxin (Kociba et al?Do we believe the lowest dose data from the megamouse study?If not why does not someone repeat the data?

  15. Acknowledgments to many collaborators over the yearsparticularlyEAC CrouchGay GoodmanIgor LinkovGeorge Gray

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