required for life hemoglobin cytochromes DNA repair catalase iron fortification

1. Fe++ Fe+++ • required for life • hemoglobin • cytochromes • DNA repair • catalase • iron fortification • excess dangerous • oxidative stress • ‘food’ for invaders • cancer • heart disease • give blood?

2. Iron too little anemia much of the 20th century spent trying get iron into people ? too much cancer since mid-1970s, growing concerns about too much iron

3. William Crosby(1914 - 2005) “The safety of iron-fortified food” JAMA 1978. • WWII veteran - Bronze star • pioneer of modern hematology • 1951: established hematology and oncology specialties at Walter Reed Army Hospital • over 450 publications

4. Biological Rationale • Iron as food to a cancer cell • iron is an essential nutrient • animal experiments • Iron and oxidative stress • DNA damage • iron as radiosensitizer

5. C ++ Fe ++ Fe ++ Fe ++ Fe carcinogen food C C C C C N C C C C C Normal cell Cancer cell Cancer O + H O 2 2 2 ++ Fe •OH DN NA Stevens & Kalkwarf, Environ Health Perspec, 87:291–300, 1990

6. Animal Experiments • Breast • diet - Thompson HJ, Carcinogenesis, 12:111, 1991 • diet - Hann H, Cancer Res, 48:4168, 1988 • Lung • diet - Yano T, Cancer Letters, 76:57, 1994 • Liver • injection - Smith AG, Carcinogenesis, 11:437, 1990 • Colon • diet - Siegers CP, Cancer Letters, 65:245, 1992

7. Relevant Iron • High iron content of blood and interstitial fluid in a form that can be utilized by cancer cells; e.g., high transferrin saturation • High intracellular iron content in a form that can engage in pro-oxidant reactions; e.g., with DNA, ferritin, and non-specific iron complexes such as ATP•Fe++ Stevens et al., N Engl J Med, 319:1047-52, 1988

8. Potentially Reactive Iron in Cells • Ferritin • Whiting et al., Cancer Res, 41:1628, 1981 • Nelson & Stevens, Cell Prolif, 25:579, 1992 • DNA-iron complexes • Loeb et al., PNAS, 85:3918, 1988 • Imlay & Linn, Science, 240:1302, 1988 • Other complexes, e.g., ADP•Fe++ • Floyd, Arch Biochem Biophys, 225:263, 1983 • Graf et al., J Biol Chem, 259:3620, 1984

9. Epidemiology IN GENERAL: high body iron is reflected in high serum ferritin and transferrin saturation and low TIBC and serum transferrin Syllogism: IF: high body iron increases cancer risk THEN: cancer should be associated with high serum ferritin and transferrin saturation and low TIBC and serum transferrin prior to development of disease

10. Blumberg: ‘Australia antigen’ led to discovery of HBV Gajdusek: Kuru disease in New Guinea led to discovery of Prions

11. Taiwan studies of HBV • study begun in 1975 • male government workers aged 40 to 59 initially • funded by NIH and by Taiwan National Science Council R. Palmer Beasley

12. co-factors: why do some HBV carriers get PHC and not others?

13. Cancer Risk in NHANES IMen and Women Combined Stevens et al., NEJM, 319:1047, 1988; Int J Cancer, 56:364, 1994

14. Cancer MortalityMen and Women Separately

15. Moderate Iron Excess U.S. and Finland real? Knekt et al., Int J Cancer, 56:379, 1994

16. Breast Cancer Study from Hiroshima • Nested case-control design • Interactions among 3 factors: • Estradiol (Kabuto et al., CEBP, 9:575,2000) • Radiation dose (Land et al., JNCI, 65:353, 1980) • Iron (Stevens et al., Radiat Res, 153:844, 2000) • Known risk factors

18. dropped at 8:15 in the morning, August 6, 1945 - clear skies, a nice day in Hiroshima exploded 1 minute later at about 500 meters above the city

19. 3 km circle

20. Nested Case-control Study of Body Iron and Breast Cancer Rick in Japanese Atomic Bomb Survivors • do women with higher body iron have greater risk of breast cancer? • are women with higher body iron more sensitive to radiation for causing breast cancer? • what is ‘body iron’?

21. Nested Case-control Study THE PAST THE PRESENT find and identify cases save: biological samples, medical info., questionnaire sample from risk set controls assay samples Cohort Population calculate odds ratio

22. Epidemiology IN GENERAL: high body iron is reflected in high serum ferritin Syllogism: IF: high body iron increases breast cancer risk THEN: women with breast cancer should have higher serum ferritin than women without breast cancer

23. Life Span Study 94,000 survivors and 27,000 unexposed (out of city on August 6)

24. Adult Health Study 20,000 enrolled in AHS for annual physical exams; blood samples taken every two years beginning in 1969

25. on 7/15/1984, a 57 yo woman is diagnosed year 1970 1990 2001 10,000 8,300 6,100 persons in cohort 9,350 still in cohort 7/15/84 - but only 52 cancer-free women aged 57 select 2 or 3 of the 52 randomly as control Risk Set cohort study of breast cancer and body iron (serum ferritin) begun in 1970 which saved blood sample from 10,000 females will do nested case-control study of cases up to 2001

26. Risk Set • retrieve the blood sample from storage for the 57 year old case and her control • assay sample for ferritin • repeat this process for all cases which occur up until 2001 • analyze data – Logistic regression

28. back to genetic iron overload conditions

29. Editorial, Nature Genetics, August, 1996 At a small meeting in the Wasatch mountains in the late 1970s, there was discussion of an iron-overload disease gene associated with an HLA region on chromosome 6. “After months of further discussion, Botstein, Davis, Skolnick and Ray White proposed the framework for a comprehensive genetic map, culminating in 1980 in their classic publication.” Hemochromatosis “…is now recognized as one of the most common single-gene hereditary disorders [among EuroAmericans]…with a remarkable carrier frequency of 1 in 10”

30. Hereditary Hemochromatosis • HH results in morbid iron overload • HH afflicts 1 in 200-400 individuals of Northern European descent • 1 in ~10 are carriers (i.e., heterozygotes) • HFE - chromosome 6p • two missense alterations, homozygous in 83% of 178 HH patients Feder et al., Nature Genetics, 13:399-408, 1996

31. Cancer in Hemochromatosis • Bradbear et al. (JNCI, 1985) • 208 subjects • 16 liver cancers - 0.07 expected • 4 colorectal cancers - 1.8 expected • Niederau et al. (NEJM, 1985) • 163 subjects • 16 liver cancers - 0.07 expected • 7 “other” cancers - 5.3 expected

32. Hemochromatosis(based on pedigree HLA linkage)transferrin saturation conventional wisdom: this can’t be a problem conventional wisdom: this is a problem normal heterozygotes homozygotes males 32.8 % 42.6 % 93.0 % females 30.2 % 40.1 % 83.7 % Bulaj et al., N Engl J Med, 335:1799-805, 1996

33. Iron Overload in Africa(Interaction between a Gene and Dietary Iron Content) • traditional beer brewed in iron pots (Zimbabwe) • propensity for iron-overload from beer drinking follows Mendelian pattern, however: • not HLA-linked (i.e., not HFE) • estimate that 3 to 4% homozygotes, ~30% heterozygotes Gordeuk et al., N Engl J Med, 326:95, 1992

34. Ferroportin • chromosome 2q32 • Q248H polymorphism associated with elevated ferritin in Africans and in African Americans • also associated with elevated serum C-Reactive Protein Rivers CA, et al., Blood Cells, Mol Dis, 38:247, 2007 McNamara L, et al. J Gastro Hepatol, 20:1855, 2005

35. what about iron in cancer prognosis?

37. Iron and breast cancer prognosis • publically available microarray data on 674 breast cancer cases • divided into ‘test’ and ‘training’ groups • ‘fooled around’ in the ‘training’ group to find best predictor of 5-year survival • 16 gene ‘Iron Regulatory Gene Signature’ • applied to ‘test’ group • strongly associated with survival after adjustment for other known prognostic indicators

38. cites the epidemiology

39. Frank Torti

40. Suzy Torti