Lipid-soluble antioxidants: β-carotene and α-tocopherol levels in breast and gynecologic cancers

Free radical-induced damage is etiologically implicated in many chronic diseases including cancer. Epidemiologic data suggest an association between increased dietary intake of nutrients that are high in antioxidant vitamins and protection against the incidence of some human cancers. The purpose of this study was (a) to determine whether specific tissue antioxidants (β-carotene and α-tocopherol) and any differences in their levels were measurable in randomly selected human breast and gynecologic malignant neoplasms and nonneoplastic tissue samples obtained from the same patient and (b) to establish normal ranges of these two antioxidant levels in human female reproductive tract tissues. Tissue samples were excised immediately from surgical specimens and released by staff pathologists from a spectrum of human female cancers. Neoplastic and adjacent nonneoplastic tissues samples were obtained from the same patient. Normal reproductive tract tissue samples were obtained from women undergoing hysterectomy for benign gynecologic conditions. Breast carcinoma and adjacent nonmalignant tissue specimens were obtained from women undergoing mastectomy. The concentrations of β-carotene and α-tocopherol were measured by high-pressure liquid chromatography. In the same patient, β-carotene levels were significantly lower in the cervical (P < 0.01) and endometrial (P < 0.005) carcinoma tissues than the levels detectable in adjacent nonneoplastic sites. In contrast, β-carotene levels were higher in the ovarian (P < 0.05), breast (P < 0.005), and vulva (P < 0.05) carcinoma tissues. The α-tocopherol concentrations were significantly higher in the cancer tissues of cervix (P < 0.01) and endometrium (P < 0.001) than those in adjacent noninvolved tissue sites. The tissue concentrations of α-tocopherol in malignant and adjacent normal sites in breast, ovary, and vulva were comparable. For the first time, the ranges for β-carotene and α-tocopherol levels in the normal female reproductive tract tissues were also established. The present findings of contrasting tissue levels of the antioxidants (β-carotene and α-tocopherol) in breast, cervix, endometrium, ovary, and vulva cancers and in nonneoplastic tissues of the same patient suggest an organ-specific and heterogenous distribution. These antioxidants appear to be essential nutritional requirements of the human female reproductive tract and breast and are implicated in the pathophysiology and carcinogenesis of these human organs. The findings require further study of the role of these antioxidant nutrients in epithelial cell proliferation, maturation, and differentiation.