Evaluation of biomarkers of oxidative stress and female reproductive hormones in post menopausal women with breast cancer in Southern Nigeria.

Abstract

Reproductive hormones and reactive oxygen species produced by either hormonal or aerobic metabolism have been implicated in carcinogenesis of the breast and disease progression. Perturbations in the homeostasis of female reproductive hormones and oxidative stress indices in breast cancer (BCa) could be used for monitoring disease prognosis. The aim of this study was to assess levels of some biomarkers of oxidative stress and female reproductive hormones in postmenopausal women with BCa at different stages. Reduced glutathione (GSH), total antioxidant capacity (TAC), total plasma peroxides (TPP), nitric oxide (NO), malondialdehyde (MDA), estradiol (E2), and prolactin (PRL) levels were determined in 50 post-menopausal women with BCa (stages II-IV) and 50 women without BCa (controls) by colorimetry and ELISA methods. Oxidative stress and body mass indices (OSI &BMI) and clinical history were obtained. Post-menopausal women with BCa had significantly higher BMI (26.60 ± 5.17 vs 22.73 ± 1.21 kg/m2, P=<0.001), TAC (5.59 ± 2.38 vs 4.43 ± 2.66 mmol/l, P = 0.023), TPP (4.92 ± 3.59 vs 2.98 ± 2.82 mmol/l, P = 0.003), NO (31.96 ± 10.73 vs 23.92 ± 6.37 μmol/l, P=<0.001) and E2 (78.89 ± 54.54 vs 11.08 ± 14.80 pg/ml, P = 0.003) levels and lower mean age at menarche (13.16 ± 0.87 vs 14.14 ± 1.60 years, P=<0.001) compared to controls. Controls had significantly lower E2 (P = 0.003), TPP (P = 0.005) and OSI (P = 0.043) compared to women with stage II BCa; lower E2 (P=<0.001), NO (P = 0.010), TAC (P = 0.010) and TPP (P=<0.001) compared to stage III BCa; and lower E2, (P=<0.001), NO (P = 0.044) and MDA (P = 0.020) compared to stage IV BCa respectively. Prolactin correlated positively with E2 (r = 0.296, P = 0.037), and TAC (r = 0.336, P = 0.011) in women with BCa. Postmenopausal women with BCa at different stages have increased estradiol, antioxidants, lipid peroxidation, and oxidative stress index suggesting that these indices may be useful for clinical assessment and monitoring progression of breast cancer.