Estrogen and progesterone receptor status in breast cancer in Kuwait female population.

The levels cytosol estrogen (ERc) and progesterone (PRc) receptors were determined in 315 primary breast cancers of female Arab patients aged 23-80 years. Most of breast cancers (78%) occurred in women aged 21-50 years, and only 22% were in women aged 51-80 years. Breast cancers containing ERc and PRc concentrations in the range 5-50 fmol/mg of cytosol protein (mg c.p.) were found with similar frequency in women aged under or over 50 years (53% for ERc and 43% for PRc, respectively). On the other hand, breast cancers with ERc values of > 50 and > 100 fmol/mg c.p. were twice as frequent in women aged over 50 years as in women aged under 50 years. The frequency of breast cancers with PRc level of over 50 fmol/mg c.p. in women aged over 50 years was only half that in those aged under 50 years. In breast cancers of Kuwait Arab women the higher values of ERc (> 100 fmol/mg c.p.) and PRc (> 50 fmol/mg c.p.) were less frequent than in other populations reported in literature. The low frequency of breast cancer in postmenopausal Kuwait women is associated with low proportions of tumors with higher ERc and PRc contents. In contrast to this, data from literature indicate that in the North Western European and American populations the postmenopausal incidence rise of breast cancers is associated with increased proportions of tumors with higher ERc and PRc levels.

Hormone sensitivity in breast cancer: influence of heterogeneity of oestrogen receptor expression and cell proliferation.

The percentage of oestrogen receptor (ER) positive cells in a series of 118 breast cancers has been examined by immunohistochemistry in relation to patients' response to endocrine therapy. Positive and negative predictive values have been used to calculate appropriate cut-off points. The rate of response to treatment was significantly higher in women with receptor positive tumours, especially where the tumours contained more than 70% positive cells. Tumours that were apparently negative for ER expression rarely responded to endocrine therapy. The hormone sensitivity of ER positive breast cancer was also influenced by the rate of tumour cell proliferation, with tumours expressing high levels of Ki67 immunostaining rarely responding to therapy.

Estrogen deprivation in breast cancer. Clinical, experimental, and biological aspects.

The endocrinological and clinical effects of an LH-RH agonist, Zoladex, and an antiestrogen, Nolvadex, in patients with advanced breast cancer are outlined and their potential in the therapy of nonmalignant diseases of the breast and high-risk states is briefly discussed. Additional data are presented to indicate that new antiestrogens are now available for experimental studies that, unlike tamoxifen, do not possess partial estrogen-like activity and that show favorable antitumor properties against DMBA-induced mammary tumors and MCF-7 human breast cancer cells in culture. The lack of agonistic effects of this new class of pharmacological agents now allows a state of total estrogen deprivation to be approached, a previously unobtainable clinical goal.

Ki67 immunostaining in primary breast cancer: pathological and clinical associations.

Ki67 immunostaining has been performed on 136 primary breast cancers and related to various clinical and pathological features of the disease. Staining was most frequently seen in poorly differentiated tumours showing high rates of mitotic activity, but was independent of tumour size, lymph-node status and ER expression. A high level of Ki67 immunostaining was often associated with early recurrence of breast cancer after mastectomy. These data are consistent with the concept of the Ki67 antibody detecting an antigen that is closely related to cell proliferation and thus provides a clinically useful marker for this important characteristic of the tumour.

Immunocytochemical localization of estrogen receptor in human breast tissue.

An immunocytochemical assay for the measurement of estrogen receptor (ER-ICA; Abbott Diagnostics) has been evaluated in 163 human breast carcinomas. Specific binding was observed in the nuclei of 111 of 163 (68%) tumors. An excellent correlation was observed between the ER-ICA and the estrogen receptor enzyme immunoassay. A significant relationship was observed between ER-ICA status and percentage of ER-ICA negative cells, histological grade of malignancy, and mitotic activity of the tumors. A significant correlation was also observed between ER-ICA status and age at mastectomy with 50% of patients with ER-ICA positive breast tumors presenting with their disease over 60 years of age. No association was observed with either tumor size or patient nodal status. Examination of the proportion of negative cells within tumors revealed a trend for the acquisition of poor prognostic features to be associated with an increase in the negative cell population. Data on the recurrence free interval of these patients showed a significant recurrence free advantage in ER-ICA positive patients, particularly those whose tumors contained low numbers of negative cells.