The antineoplasic effect of molecular iodine on human mammary cancer involves the activation of apoptotic pathways and the inhibition of angiogenesis.

Abstract

Abstract Abstract #3082 Breast cancer is the most frequent malignant neoplasia in women. One factor thought to influence the incidence of breast cancer is diet. Japanese women, who have a high dietary intake of iodine (5280 vs 209 µg/day in western population) due to ingestion of seaweed, have the lowest incidence of breast cancer in the world. In normal mammary gland, iodine deficiency is involved in dysplasias, which are reversible with I2 but not with iodide administration. Recent data generated in our laboratory showed that continuous treatment with I2, but not iodide, has a potent antineoplastic effect on tumoral progression in N-methyl-N-nitrosourea-treated virgin rats (50-70%). Also I2 treatment in MCF-7 human breast cancer cells, but not in normal mammary cells (MCF-12F), shows a significant apoptotic effect induced by activation of Bax-caspases and AIF-PARP-1 pathways. Based on these findings, a study of women diagnosed with cancer (mammography and tru-cut biopsy) was initiated. Patients were divided into placebo or I2 (5 mg/day) groups for 2 to 5 weeks before surgery. One day before beginning the I2 treatment and the day of the surgery, urine and blood samples were collected. The day before surgery, a second mammography was obtained. In the tumor samples proliferation (PCNA), apoptosis (TUNEL), and vasculature area (CD-31) were analyzed by immunohistochemistry. Bax, Bcl2, p53, and VEGF proteins were analyzed by Western blot. Circulating TSH and T3 levels were measured by RIA and urinary iodide by HPLC. The results showed that although tumor size did not differ between groups, a significantly lower proliferation and increased apoptotic rate were observed in tumors from women supplemented with iodine. In these tumors the ratio Bax/Bcl2 increased, p53 levels were unchanged, and VEGF levels and vasculature area diminished significantly. Serum TSH and T3 showed no changes in any group, indicating that I2 treatment had not compromised the thyroid status. We propose that I2 supplements should be considered for use in clinical trials of breast cancer therapies. We thank Dr. Jorge Álvarez-Aguirre2,3, Dr. Alonso Gallegos-Corona2, Lic. Concepción Correa-Tinajero3, Alejandro Núñez-Nolasco2,3, and Silvia Serrato-Águila2. This work was partially supported by: PAPIIT-UNAM IN201207, and CONACyT 44976-M and 85952. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3082.