Serum hormone levels in breast cancer patients and controls in Egypt and Great Britain. The Anglo-Egyptian Health Agreement Collaborative Study

High levels of oxidative DNA damage in lymphocyte DNA of premenopausal breast cancer patients from Egypt

Egypt shows a parallel increase in premenopausal breast cancer and environmental pollution. The purpose of this study is to explore a possible relationship between oxidative DNA damage, urinary estrogen metabolites and breast cancer in Egyptian premenopausal women. We conducted a pilot study of Egyptian breast cancer involving 29 cases and 32 controls and analysed lymphocyte DNA levels of 7,8-dihydro-8-oxo-2'-deoxyguanine (8-oxo-dG), a measure of oxidative DNA damage using high performance liquid chromatography with electro-chemical detection (HPLC-ECD) method. We analysed levels of urinary estrogen metabolites, 2-hydroxyestrone (2-OHE) and 16alpha-hydroxyestrone (16alpha-OHE) by an enzyme immuno assay. We also collected residential, occupational, and reproductive histories of all study subjects. We detected, in all subjects, exceptionally high levels of 8-oxo-dG and thus oxidative DNA damage, the levels (mean 8-oxo-dG/10(5) dG+/-SD) were significantly (P<0.01) higher in breast cancer cases (139.4+/-78.4) than in controls (60.9+/-51.5). Urinary 2-OHE and 16alpha-OHE or their ratio was not significantly different between cases and controls. However, 8-oxo-dG levels were positively correlated (P<0.05) with 2-OHE and 16alpha-OHE from cases while controls showed a negative correlation (P<0.05). Urban residence (Odds Ratio [OR] 3.1; Confidence interval [CI], 1.1-9.3), infertility (OR [9.8]; CI [1.1-89.7]), age (OR [2.6]; CI [1.4-4.6]) and 8-oxo-dG (OR 5.8; CI 1.9-17.5) levels were found to be significant predictors of breast cancer. Our finding of exceptionally high levels of 8-oxo-dG, a common result of oxidative DNA damage, warrant future studies on a larger population of premenopausal women in Egypt with consideration of other susceptibility markers and dietary characteristics.

Serum organochlorine levels and history of lactation in Egypt

We conducted a study in Egypt to assess the determinants of organochlorine serum levels among premenopausal women and the risk of premenopausal breast cancer for women with high organochlorine serum levels. We included 69 breast cancer patients and 53 controls consisting of visitors to the hospitals of the cancer patients. We found low levels of dichlorodiphenyldichloroethylene (DDE), total dichlorodiphenyltrichloroethane, and beta-hexacholorhexane (beta-HCH) in most subjects. Mean DDE levels were 12.7 +/- 20.3 ppb for cases and 16.6 +/- 30.1 ppb for controls (P = 0.60); beta-HCH levels were 2.1 +/- 3.8 ppb for patients and 2.1 +/- 3.9 ppb for controls (P = 0.71). Interestingly, subjects with low levels had breast fed their children for an average period of 18 months. Women with no lactation history had much higher organochlorine levels than women who breast fed (P = 0.002 for DDE). Younger age, older age at first childbirth, and shorter duration of breast feeding were significant predictors of higher levels of serum DDE levels. Younger age, older age at first childbirth, and higher body mass index were significant predictors of higher beta-HCH levels. This study suggests that organochlorine serum levels in Egyptian women are quite low, but indicates an effect of breast feeding in eliminating organochlorines, which would imply exposure to children. Organochlorine serum level was not a risk factor of breast cancer in this population.

Geographical variation in endocrine function and its relation to breast cancer incidence: some general considerations

Abnormalities in endocrine function are not a determinant of risk of breast cancer within countries, and racial differences in this function do not explain geographical variation in risk. It is suggested that hormonal status is related to tumor growth rates and hence to age at diagnosis, recurrence rates after primary treatment, and survival. Such evidence as there is points in this direction, but it still remains to be finally established whether the disease runs a similar course in all countries when patients are standardised for factors known to affect prognosis.

Serum hormone levels in British and rural Chinese females

The comparison of blood levels of oestradiol, testosterone, prolactin, and sex-hormone binding globulin (SHBG) was made of 3250 rural Chinese and 300 British women, aged 35 to 64. To reduce the number of assays performed the blood samples were combined so as to form 390 and 30 pools, respectively. The Chinese had significantly less oestradiol and testosterone. Prolactin levels were similar in both races. SHBG was significantly lower in postmenopausal British women. In the Chinese women, testosterone was positively and prolactin negatively correlated with breast cancer mortality.

Sex hormones in women in rural China and in Britain

Plasma concentrations of certain hormones linked to breast cancer risk were measured in age-pooled samples from 3,250 rural Chinese women in 65 counties, and 300 British women, all aged 35-64. In age-groups 35-44, 45-54 and 55-64 respectively, mean oestradiol concentrations were 36% (P = 0.043), 90% (P less than 0.001) and 171% (P = 0.001) higher in the British than in the Chinese women, and mean testosterone concentrations were 48% (P less than 0.001), 68% (P less than 0.001) and 53% (P = 0.001) higher in the British than in the Chinese women. The difference in testosterone concentrations between the two countries appeared to be due largely to the lower average body weight in the Chinese women. Sex hormone binding globulin did not differ significantly between the two countries in age groups 35-44 and 45-54, but was 15% (P = 0.002) lower in the British than in the Chinese women at ages 55-64. Prolactin concentrations did not differ significantly between the two countries in any age group.

The distribution of estradiol in the sera of normal Caucasian, Chinese, Filipina, Hawaiian and Japanese women living in Hawaii

Mean concentrations of sex-hormone-binding-globulin (SHBG) and the percentage distribution of estradiol between the non-protein-bound, albumin-bound and SHBG-bound fractions were not different in Caucasian, Hawaiian, Chinese, Japanese and Filipinas living in Hawaii. The widely varying incidence rates for breast cancer are therefore not explained by variations in the availability of estradiol.