Because of evidence that increased body iron stores are associated with an increased risk of cancer, we examined iron status and cancer risk in the first National Health and Nutrition Examination Survey, a survey of more than 14,000 adults begun in 1971, with follow-up between 1981 and 1984. Among 242 men in whom cancer developed, the mean total iron-binding capacity was significantly lower (61.4 vs. 62.9 mumol per liter; P = 0.01) and transferrin saturation was significantly higher (33.1 vs. 30.7 percent; P = 0.002) than among 3113 men who remained free of cancer. The risk of cancer in men in each quartile of transferrin-saturation level relative to the lowest quartile was 1.00, 1.01, 1.10, and 1.37 (P = 0.02 for trend). The serum albumin level was significantly lower in men in whom cancer developed than in those who remained cancer-free. Among women, those in whom cancer developed did not have significantly lower total iron-binding capacity or higher transferrin saturation than those who remained cancer-free. However, a post hoc examination of 5367 women (203 with cancer) yielded a relative risk of 1.3 (95 percent confidence interval, 0.9 to 1.9) associated with a very high transferrin saturation (greater than or equal to 36.8 percent, a value in the highest quartile among men); in 5228 women with at least six years of follow-up (149 with cancer), the relative risk associated with transferrin saturation above this level was 1.5 (1.0 to 2.2). These results are consistent with the hypothesis that high body iron stores increase the risk of cancer in men. The possibility that a similar association exists in women requires further study.

Body Iron Stores and the Risk of Cancer

Iron-induced carcinogenesis: the role of redox regulation.

Purpose: Endometriotic cysts are known to transform into ovarian cancers, such as clear cell and endometrioid carcinomas. We hypothesized that an iron-rich environment produced by the repetition of hemorrhage in the endometriotic cysts during the reproductive period may play a crucial role in carcinogenesis in the cysts through the iron-induced persistent oxidative stress. Experimental Design: Contents of human ovarian cysts, including 21 endometriotic cysts, 4 clear cell carcinomas, and 11 nonendometriotic cysts, were analyzed for the concentrations of free “catalytic” iron, lactose dehydrogenase, potential antioxidant, lipid peroxide, and 8-hydroxy-2′-deoxyguanosine (8-OHdG). Iron deposition and 8-OHdG levels were also analyzed histologically. Reactive oxygen species and the mutagenicity of the contents in endometriotic cyst were determined in vitro . Results: The concentration of free iron in endometriotic cysts (100.9 mmol/L) was significantly higher than that in nonendometriotic cysts (0.075 mmol/L; P P P P P In vitro analyses showed that the contents of endometriotic cyst could produce more reactive oxygen species and could induce gene mutations more frequently than the contents in the other cysts. Conclusions: Abundant free iron in the contents of endometriotic cysts was strongly associated with greater oxidative stress and frequent DNA mutations. A long-standing history of the RBCs accumulated in the ovarian endometriotic cysts during the reproductive period produces oxidative stress that is a possible cause for the malignant change of the endometriotic cyst.

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Contents of Endometriotic Cysts, Especially the High Concentration of Free Iron, Are a Possible Cause of Carcinogenesis in the Cysts through the Iron-Induced Persistent Oxidative Stress

(1990). Cellular Iron Metabolism in Health and Diseased. Drug Metabolism Reviews: Vol. 22, No. 5, pp. 531-579.

Cellular iron metabolism in health and disease.

Relative impact of HLA phenotype and CD4-CD8 ratios on the clinical expression of hemochromatosis

The present investigation was motivated from the consideration that a host environment rich in iron, represented by high serum transferrin saturation (TS) and high serum iron and serum ferritin levels might offer favorable growth conditions for leukemic cells in addition to infection, thus affecting survival. Serum measurements were obtained on 113 pediatric patients with acute lymphoblastic leukemia (ALL), seen at Memorial Sloan-Kettering Cancer Center between May 20, 1981 and August 8, 1983. A significant difference (p less than 0.001) was found between the survival of patients according to whether their first measured TS was greater than 36% or less than 36%, with fewer deaths in the group with TS less than 36. The relationship between TS and survival was still observed when patients were stratified according to length of time from diagnosis, risk group, French-American-British (FAB) classification, or presence of organomegaly at diagnosis (p less than 0.001). Similar differences were observed between survival of patients grouped according to their first measured serum ferritin. These results independently confirm and extend observations presented earlier and support the consideration that motivated this study. The value of serum iron-related measurements as prognostic variables cannot be established from this type of study; however, these findings suggest the need for a prospective study.

Miller D

Papers

Association of serum iron, serum transferrin saturation, and serum ferritin with survival in acute lymphocytic leukemia.