Endocrine therapy of metastatic breast cancer

Multicomponent Materials to Improve Solubility: Eutectics of Drug Aminoglutethimide

Here, we report the synthesis and experimental characterization of three drug-drug eutectic mixtures of drug aminoglutethimide (AMG) with caffeine (CAF), nicotinamide (NIC) and ethenzamide (ZMD). The eutectic mixtures i.e., AMG-CAF (1:0.4, molar ratio), AMG-NIC (1:1.9, molar ratio) and AMG-ZMD (1:1.4, molar ratio) demonstrate significant melting point depressions ranging from 99.2 to 127.2 °C compared to the melting point of the drug AMG (151 °C) and also show moderately higher aqueous solubilities than that of the AMG. The results presented include the determination of the binary melt phase diagrams and accompanying analytical characterization via X-ray powder diffraction, FT-IR spectroscopy and scanning electron microscopy.

In situ hybridization of chromosome 6 on fine-needle aspirates from breast carcinomas: comparison of numerical abnormalities and ER/PgR status and staining pattern

The estrogen receptor (ER) gene is located on chromosome 6. The aim of our study was to investigate whether numerical chromosomal aberrations were reflected in estrogen/progesterone receptor (PgR) status and staining pattern. Fine-needle aspirates from 51 breast carcinomas were investigated immunocytochemically for ER/PgR and by in situ hybridization technique using digoxigenin-labeled alpha-satellite probe for chromosome 6. Cases with > or = 70% two-signal nuclei were regarded as disome; the remaining tumors showed aneusomy with a variable number of signals. Aneusomy was found in 32 tumors (63%), whereas 19 (37%) had a normal number of chromosome 6. Chromosomal gain occurred in all aneusome cases except one. ER- and/or PgR-positive tumors had an equal distribution of disomy and aneusomy. Variable ER staining pattern or ER and/or PgR negativity was associated with numerical aberrations in chromosome 6 in 76% of the tumors. Cancers with uniform ER staining pattern all had normal chromosome number.

Determination of oestrogen responsiveness of breast cancer by competitive reverse transcription-polymerase chain reaction

Competitive polymerase chain reaction assays have been developed for the quantitation of oestrogen receptor mRNA and two oestrogen-regulated mRNAs (progesterone receptor and pNR-2/pS2) in breast cancer cells. These assays are more sensitive than traditional hybridisation techniques, do not require the use of radioisotopes, measure absolute amounts of messenger RNAs and can be used to measure the expression of mRNAs in small numbers of tumour cells obtained by fine-needle aspiration (FNA). These assays should prove useful for predicting the hormone responsiveness of breast cancer from tumour cells obtained by FNA at diagnosis and could be particularly useful in the management of elderly/frail patients who receive primary tamoxifen, or in other patients for whom tumour tissue for standard biochemical measurements is not available.

Relationship between low estrogen receptor values and other prognostic factors in primary breast tumors

BACKGROUND

The current study compared the immunocytochemical expression of estrogen (ER) and progesterone (PgR) receptors by malignant breast cells to the hormone receptor concentrations reported from radioligand assays. These values were examined in relation to DNA ploidy and the fraction of cells in S phase.

METHODS

ER and PgR concentrations, DNA ploidy, and S-phase fractions were measured by standard techniques with 124 samples of invasive ductal carcinoma. Suspensions of tumor cells were examined by immunocytochemical assay (ICA) for the percentages of ER and PgR positive cells.

RESULTS

Twenty-six of the 38 tumors from patients 50 years of age or younger were classified as high S-phase fraction, and 28 tumors had aneuploid levels of DNA. The 20 ER positive tumors each contained less than 100 fmol/mg. Thirty-nine of the 86 tumors from patients older than 50 years were classified as high S phase, and 41 were aneuploid. Sixty-five samples were considered ER positive by radioligand assay. ICA showed that tumors in either age group with less than 40 fmol/mg did not contain ER positive cells. The proportion of samples with PgR levels between 10 and 100 fmol/mg was small, and fewer PgR positive tumors were categorized as negative when examined by ICA for receptor containing cells. The reclassification of the hormone receptor status of a tumor based on ICA appeared to be independent of S-phase and ploidy values.

CONCLUSIONS

Tumors that are classified as ER or PgR positive based on accepted cutoff values for radioligand assays may actually be receptor negative because the tumors do not appear to contain receptor positive cells.

Immunocytochemical staining of pS2 protein in fine-needle aspirate from breast cancer is an accurate guide to response to tamoxifen in patients aged over 70 years

Fine-needle aspirates from 52 breast cancers in 50 patients over 70 years of age were immunocytochemically stained for pS2 protein. All patients were treated with tamoxifen 40 mg/day and followed up at intervals of 2 months. The size of the tumour was serially assessed with calipers and portable ultrasonography. Change in tumour size was confirmed mammographically. Clinical monitoring was performed bind of the pS2 status. Twenty-five tumours were pS2 positive, of which 23 showed a significant response; ten went into complete remission (mean time to complete remission 6.8 (range 2-14) months) and 13 demonstrated partial remission (mean follow-up 8.9 (range 6-19) months). Two tumours remained static. Twenty-seven tumours were pS2 negative and none of these responded to tamoxifen; six remained static (mean follow-up 11.5 (range 6-14) months) and 21 progressed (mean time to progression 7.0 (range 3-14) months) (P < 0.001). Immunocytochemical assessment of fine-needle aspirates from elderly women with breast cancer accurately predicts a worthwhile response to tamoxifen.

Expression of the pS2 protein and correlation with estrogen receptor status in fine-needle aspirates from breast carcinomas

A series of 36 cases of breast carcinomas diagnosed by fine-needle aspiration were investigated for the presence of estrogen receptors (ER) and the estrogen-induced pS2 protein. Immunocytochemically ER could be demonstrated in 28 aspirates, whereas eight were negative. These eight were also negative for the pS2 protein. In addition three aspirates with a low score for ER and five with a high score for ER were found negative for pS2. Thus, of the 36 cases, 20 were found to express the pS2 protein. The presence of the pS2 protein in the tumor cells is believed to be a marker of a functional estrogen regulatory system and its demonstration may therefore predict clinical responsiveness to hormonal therapy.

cDNA transfection followed by the isolation of a MCF-7 breast cell line resistant to tamoxifen in vitro and in vivo

A tamoxifen resistant cell line (clone 9) has been isolated from the tamoxifen sensitive, hormone responsive MCF-7 breast carcinoma cell line after transfection with mixed cDNA libraries, followed by tamoxifen selection in the presence of oestrogens. Transfection was confirmed by Southern analysis with vector probes. Clone 9 in several-fold more resistant to tamoxifen and other anti-oestrogens than wild type cells when cultured either as a monolayer or as colonies in soft agar but retains oestrogen receptors. Clone 9 was less responsive to 17-beta-oestradiol than were wild type MCF-7. In addition to showing in vitro tamoxifen resistance, clone 9 was also tamoxifen resistant in vivo when xenografted into the nude mouse. Culture medium conditioned by clone 9 cells stimulated quiescent cells of the same clone as well as wild type cells, whereas medium conditioned by wild type MCF-7 was inhibitory to both, suggesting that clone 9 may be secreting an autocrine growth factor. Clone 9 provides a novel model for further investigation of the mechanism of anti-oestrogen resistance that occurs without loss of oestrogen receptors. Preliminary results suggest that an autocrine growth stimulatory mechanism may be one pathway of such resistance.

Truncated forms of DNA-binding estrogen receptors in human breast cancer

The likelihood a breast cancer will respond to antiestrogen therapy depends on the tumor content of immunoreactive or ligand-binding estrogen receptor (ER). To investigate the failure of many ER-positive breast cancers to respond to antiestrogen therapy, we examined by gel-shift assay the ability of tumor ER to bind its cognate estrogen response element (ERE). Analysis of 38 primary breast cancers showed that some tumors containing abundant immunoreactive ER failed to demonstrate DNA binding ER. In many other ER-positive tumors, the fraction of DNA binding ER was low and consisted primarily of truncated receptor forms, which on Western analysis were revealed to be 50 kD homodimers and 67-50 kD ER heterodimers. The use of protease inhibitors during tumor extraction and the demonstration of nuclear-localizing ER and ERE-binding COUP (chicken ovalbumin upstream promoter) protein in these tumors indicated that the truncated forms of ER were likely present in vivo. The presence of intact DNA binding ER correlated with higher tumor content of immunoreactive sex steroid receptors (ER and/or PR), standard predictors of tumor responsiveness to antiestrogen, suggesting that loss or truncation of DNA binding ER may be an important prognostic parameter accounting for some forms of clinical resistance to antiestrogen therapy.

Postoperative hyperprolactinaemia and early recurrence rate in breast cancer

Serum levels of prolactin before and after surgery were measured in 90 women with breast cancer until the 5th postoperative month. Surgery-induced hyperprolactinaemia occurred in 51 patients, without significant correlation to any other clinical variable. After a median follow-up of 39 months, irrespective of each other variable (i.e. nodal involvement, oestrogen receptor status, adjuvant therapies), patients with postoperative hyperprolactinaemia had a significantly lower recurrence rate than those in whom surgery was not followed by an abnormal increase in prolactin secretion (3/51 vs. 13/39, P less than 0.001). These results suggest that, despite the stimulatory role of prolactin on mammary tumours, the lack of postoperative hyperprolactinaemia is an unfavourable prognostic factor because of its association with a higher relapse rate.