Comparison of different antibodies for detection of progesterone receptor in breast cancer

Monoclonal antibodies directed against human estrogen receptor (ER) and progesterone receptor (PR) have been used extensively for biochemical and immunohistochemical detection of receptors independent of hormone-binding assays. These antibodies have been valuable both for experimental work and for detection of receptors in clinical breast cancer specimens. The purpose of this study was to characterize the sensitivity and specificity of different antibodies for detection of PR by immunohistochemistry (IHC) of formalin-fixed paraffin breast carcinoma sections. The panel of twelve antibodies included two new ones (PgR636 and PgR1294) produced prospectively to be resistant to formalin fixation and paraffin embedding. Fifty-nine breast carcinomas, having known PR levels by biochemical ligand-binding assay, were used to prepare multitumor paraffin-embedded tissue blocks for characterization of the PR antibodies. Of all the antibodies tested, both PgR636 and PgR1294 stained the highest percentage of breast carcinomas known to be positive by the biochemical assay (95-98%) and they exhibited the highest concordance with the biochemical assay (88-90%). The PgR636 and PgR1294 antibodies, along with one other, PR 88, also gave the highest intensity of nuclear staining, while PgR636 and PgR1294 stained the highest mean percentage of tumor cell nuclei. Antigen retrieval was not necessary for PR immunostaining by PgR636 and PgR1294 in most tumors and other tissues examined, but did slightly increase the staining intensity. The majority of the other antibodies tested were highly dependent on antigen retrieval; only PR 88 and KD 68 antibodies approached the performance of PgR636 and PgR1294 without antigen retrieval. These results indicate that PgR636 and PgR1294 are optimal antibodies for IHC detection of PR in routine paraffin tissue blocks.     

Clinicopathologic Characteristics of Oestrogen Receptor-Positive/Progesterone Receptor-Negative/Her2-Negative Breast Cancer According to a Novel Definition of Negative Progesterone Receptor Status: A Large Population-Based Study from China

PurposeA lack of progesterone receptor (PgR) expression in oestrogen receptor-positive (ER+) tumours is associated with worse survival. PgR status is usually defined as positive or negative using 1% positive nuclei as a cut-off point. In this study, we aimed to assess the clinicopathologic characteristics of ER+/PgR-/HER2- tumours by comparing them with ER+/PgR+/HER2- tumours using a PgR cut-off point of 20% as a divisive criterion.MethodsWe analysed 1,522 patients with primary breast cancer who had undergone surgery at the Cancer Center of Fudan University between 2012 and 2014. Age, grade, tumour size, lymph node status and lymphovascular invasion were assessed. Multinomial logistic regression, linear regression and chi-square test models were applied to assess associations between ER, PR and clinical features.ResultsER+/PgR-/HER2- tumours showed poorer clinicopathologic characteristics relative to ER+/PgR+/HER2- tumours using a PgR threshold of 20% instead of 1%. The clinicopathologic characteristics did not differ between tumours with purely negative PgR expression and tumours with a PgR percentage ranging from 1% to 19%. The prognostic significance of PR expression appeared more pronounced in patients under a high Ki-67 status than those under a low Ki-67 status.ConclusionsBased on these findings, we propose the use of a novel threshold of 20% to define PgR status. Nevertheless, the impact of this new criterion on patient management and clinical treatment requires additional study.     

Biological and clinical effects of aromatase inhibitors in neoadjuvant therapy

Postmenopausal women with large primary oestrogen receptor-rich (>20 fmol/mg protein or 80 histoscore) breast cancers have been treated neoadjuvantly with either letrozole (2.5 or 10 mg daily n=12 in each case) or anastrozole (1 or 10 mg daily n=12 and 11, respectively). Tumour was available for analysis before treatment (wedge biopsy) and 3 months later at definitive surgery (wide local excision or mastectomy). Clinical response to treatment was assessed by sequential measurements of tumour volume based on caliper assessment, ultrasound and mammography. Results showed that in these selected groups of patients a reduction in tumour volume with treatment was observed in 43 of 47 cases (91%). Pathological responses, i.e. clear decrease in tumour cellularity or increased fibrosis was evident in 32 cases (68%). Furthermore, there was a decrease with therapy in immunohistochemical staining for Ki67 in all tumours. Staining for progesterone receptor (PgR) was reduced in all 21 PgR-positive cancers treated with letrozole and in 16 of 17 positive cancers treated with anastrozole. These effects are at least as great as those seen in a non-randomised group of patients treated with tamoxifen over the same time period (additionally tamoxifen treatment was often associated with an increase in PgR staining). The results suggest that potent specific aromatase inhibitors will be valuable in treating hormone-dependent cancers.     

Breast infiltrating ductal carcinoma: analysis of hormone, HER-2 receptors and Ki-67 proliferation marker

The aim of this study was to analyse breast carcinomas with discordant receptor status, probably hormonal dependent (estrogen receptor (ER) positive, progesterone receptor (PR) negative or ER-PR + subgroup profile) infiltrating ductal breast carcinomas not otherwise specified (IDC NOS). Specimens from 90 IDC NOS were grouped into three categories according to hormonal status: dependent (D) (ER +PR +), probably dependent (PD) (ER +PR- or ER-PR +) and non-dependent (ND) (ER-PR-); they were evaluated considering some established prognostic parameters in breast carcinomas. Statistically significant difference was found between tumor receptor status distribution and menopausal status (p = 0.0235), age of the patients (p = 0.000467), histological grade (p = 0.000003), vascular invasion (p = 0.006), HER-2 status (p = 0.0039) and Ki-67 proliferation rate (p = 0.000311). D tumors were found exclusively in post-menopausal patients (average age 68.9 years), most of which had intermediate (II) grade, without vascular invasion, with HER-2 status score predominantly 0 or 1 + and lower Ki-67 proliferation rate. PD tumors were found predominantly in younger post-menopausal patients (average age 57.5 years), with vascular invasion found in 23% of the cases. ND tumors mostly had higher histological grade, showed the highest percentage of the Ki-67 positive tumor cells and vascular invasion in 30% of the cases. We conclude that the patients with PD breast carcinomas were younger post-menopausal women with the tumors moderately differentiated, HER-2 score 0 or 1+ and with lower Ki-67 proliferation rate.     

Comparison of the oestrogen and progesterone receptor status in primary breast carcinomas as evaluated by immunohistochemistry and immunocytochemistry: a consecutive series of 267 patients

A.M. Domanski, N. Monsef, H.A. Domanski, D. Grabau and M. Fernö
Comparison of the oestrogen and progesterone receptor status in primary breast carcinomas as evaluated by immunohistochemistry and immunocytochemistry: a consecutive series of 267 patients Objective: The use of cytological specimens to evaluate tumour biomarkers in metastatic breast cancer lesions has attracted increased interest because of the considerable number of reports that have shown discordance between the primary tumour and metastatic lesion. Oestrogen receptor (ER) and progesterone receptor (PgR) assays are crucial for the management of patients with breast cancer, in both adjuvant and palliative settings. The aim of this study was to compare the ER and PgR immunocytochemical analysis of fine needle aspiration (FNA) samples with the immunohistochemistry (IHC) of surgical specimens and core biopsies from primary breast cancers. Methods: The FNA specimens were prepared as cell blocks (n = 25) or ThinPreps (n = 258) for the immunocytochemistry (IC) ER and PgR analyses. Sixteen patients were excluded because of lack of follow‐up (n = 1), neoadjuvant therapy (n = 3) or cell counts in their fine needle aspirates that were too low (n = 12). The results of IC on 25 cell blocks and 242 ThinPreps were compared with IHC on the corresponding core needle biopsies (n = 16) or excised tumours (n = 251). The ER and PgR status was defined as negative (when less than 10% of the nuclei were stained) or positive (when equal or more than 10% of the nuclei were stained). Kappa statistics were used to evaluate the concordance. Results: The ER concordance was 98% with ThinPrep (κ = 0.93) and 92% with cell block (κ = 0.82). The corresponding values for PgR were 96% (κ = 0.91) and 96% (κ = 0.92). Conclusions: Our results confirm that, in cases in which biopsies or surgical specimens are not available, IC (with either cell block or ThinPrep techniques) is a reliable method for the determination of the ER and PgR status performed under strict conditions using primary breast carcinomas, and is therefore potentially useful in metastatic settings.     

Expression of sex steroid receptors and IGF-1 mRNA in breast tissue--effects of hormonal treatment

The mechanisms behind increased breast tissue proliferation and a possibly increased breast cancer risk in women using hormonal contraception (HC) and hormonal replacement therapy (HRT) are incompletely understood. We analyzed breast tissue from 20 premenopausal and seven postmenopausal women undergoing reduction mammoplasties for estrogen receptor (ER) and progesterone receptor (PR) content as well as mRNA levels for ER, PR and insulin-like growth factor-1 (IGF-1). The receptor values were correlated to IGF-1 mRNA concentrations and levels of steroid and peptide hormones and SHBG. In women using HC, we found significantly lower ER values (p=0.02) but non-significantly lower ER mRNA levels compared to those in naturally cycling women. PR and PR mRNA were no different. Women on HC displayed a higher breast tissue proliferation (p=0.05) expressed as Ki-67, MIB-1 positivity, which was correlated with IGF-1 mRNA (r_s=0.82, p=0.04). Since the concentration of sex steroid receptors in breast tissue is comparatively low and steroid receptors are down-regulated during hormonal treatment, mechanisms other than direct sex steroid receptor action are likely to be present. Our results suggest a role for IGF-1 in the proliferative response of breast tissue during exogenous hormonal treatment.     

Sex steroid receptor expression in the oviduct and uterus of sheep with estrus synchronized with progestagen or prostaglandin analogues

The objective of this study was to investigate differences in the expression of estrogen receptor-alpha (ERalpha), progesterone receptor (PR) and the proliferative indexes (Ki-67), in the uterus and oviduct of sheep with estrus synchronized either by prostaglandin analogues (Group PA, n=27) or by treatment with progestagens (Group P, n=29) on days 4 and 7 (day 0=estrus), when the embryos were collected. Immunohistochemical methods were used to quantify ERalpha, PR and Ki-67 in six superficial and deep compartments in the uterus and oviduct. The expression of ERalpha was significantly (P<0.01) lower in progestagen treated ewes than in prostaglandin analogues treated group in the luminal epithelium, superficial glands and superficial stroma in the uterus on day 4. The expression of PR was significantly lower in progesterone treated ewes than in the PA Group in the superficial gland (P<0.05) in both days studied. The lowest expression of PR was observed in the luminal caruncular epithelium and superficial glands in both treatments, obtaining the lowest levels on day 4 (P<0.05). There were significant differences between days 4 and 7 in the Ki-67 immunostaining in the luminal epithelium (P<0.01) and superficial glands (P<0.05). A higher cell proliferation was observed in the uterine epithelium (P<0.05) on day 4 in the animals treated with progestagens. Results indicate that sheep with synchronization of estrus with progestagens showed a reduction of ERalpha and PR protein expression in most of oviductal and uterine cells.     

PCNA independence of Ki-67 expression in HPV infection.

12 Infectious Wart lesions were stained using the streptavidin-biotin immunoperoxidase method for PCNA10, MIB-1 (Ki-67 equivalent antigen) and Human Papilloma Virus antigen to study the effect of HPV presence on epidermal proliferation. Using strict methods to avoid observer bias, Ki-67 antigen was found in a high proportion of nuclei in the suprabasal layers together with HPV antigens, in the absence of PCNA staining. This finding indicates that DNA synthesis related, Ki-67 antigen bearing structures can be raised in the human nucleus in the absence of induction of PCNA bearing structures, suggesting also structural independence between the antigen bearing molecules.     

Flow cytometric analysis of estrogen, progesterone receptor expression and DNA content in formalin-fixed, paraffin-embedded human breast tumors.

Flow cytometric analysis of estrogen (ER) and progesterone (PgR) receptor expression in archival human breast tumors is relatively difficult. We have used enzyme digestion and microwave antigen retrieval procedures for multiparametric flow cytometric analysis of ER and PgR expression and DNA content in nuclei isolated from formalin-fixed/paraffin-embedded primary breast tumors. Deparaffinized rehydrated tissue sections treated with pepsin were subjected to microwave irradiation for unmasking of ER and PgR antigenic sites. Biotinylated ER antibody and streptavidin-fluorescein isothiocyanate (FITC) were used for ER labeling and PgR antibody with phycoerythrin labeled goat anti-mouse antibody was used for PgR labeling. Counter staining with propidium iodide-RNase was used for determination of cellular DNA content. Our results show that enzyme digestion and microwave treatment of formalin-fixed, paraffin-embedded breast tumors can be successfully used for the multiparametric analysis of nuclear hormone receptor expression and DNA content by flow cytometry.     

Elevated metallothionein (MT) expression in invasive ductal breast cancers predicts tamoxifen resistance

Elevated expression of the low molecular weight metallothionein (MT) proteins can be found typically in breast cancer cases with less favourable prognosis. The MT gene has been described to be potentially down-regulated by estrogen receptor alpha. The present study is aimed at examining the predictive value of MT expression for results of tamoxifen treatment in breast cancer in relation to steroid receptor status. Sixty patients with primary invasive ductal breast cancers with post-operative tamoxifen treatment were enrolled in the study. In paraffin sections of the studied tumours immmunohistochemical reactions were performed using antibodies directed against MT, estrogen receptors (ER) and progesterone receptors (PgR). Results of the immunohistochemical reactions and of clinical observations were analysed using multivariate progression analysis based on the Cox proportional hazard model. Elevated MT expression was demonstrated to be typical for cases with documented relapse of the disease (P<0.001) or terminated by death (P=0.03). Decreased ER expression was found to be typical for cases of a higher grade (P=0.02) and cases terminated by death (P=0.006). The multivariate analysis showed that elevated MT expression was characteristic for cases with shorter overall survival time (P=0.04). The data showed that MT carried an independent, and also independent from ER status, unfavourable predictive value as far as results of tamoxifen treatment were concerned.     

Immunoreactivity to MIB-1 in breast cancer: methodological assessment and comparison with other proliferation indices

The recent availability of the monoclonal antibody MIB-1 (which is able to detect the human nuclear cell proliferation-associated antigen Ki-67 even on formalin-fixed, paraffin-embedded sections, microwave-treated and routinely processed for immunohistochemistry) could open new avenues for validation of the clinical role of tumour cell proliferation on large, consecutive and unselected series of human tumours. However, the routine use of such a marker requires a methodological standardization as well as the comparative assessment of some technical and biological aspects. The MIB-1 index was determined in parallel samples from 50 consecutive invasive breast carcinomas processed with different fixatives for different times. The median values of MIB-1 indices following 2, 6 and 24 h of formalin fixation were similar (29.4%, 30.6% and 29.7%, respectively) and consistent with those reported in the literature; squared linear regression coefficients were 0.99. The median values of MIB-1 indices were markedly lower in Bouin-fixed, paraffin-embedded, and in frozen samples (20.0% and 19.8%, respectively), with a poor correlation coefficient with the values detected following formalin fixation ( R ²=0.456). Moderate and poor correlations were observed between Ki-67 index and MIB-1 detected on frozen ( r _s, 0.78) or formalin-fixed, paraffin-embedded samples ( r _s, 0.47) and a minimal concordance was observed between TLI and MIB-1 or Ki-67 ( r _s, 0.25 and 0.22, respectively). Our results indicate interference of the fixative type on immunoreactivity to MIB-1 and also suggest that Ki-67 and MIB-1 reacted with different epitopes of the same antigen.     

A progesterone receptor affinity chromatography reagent: 17α-Hexynyl nortestosterone sepharose

Several affinity chromatography reagents have been proposed for purification of progesterone receptor (PgR), and significant results have been achieved with some of these. None, however, have approached the results achieved in affinity chromatography of estrogen receptor. We have therefore synthesized a number of new 19-nortestosterone derivatives capable of chemically stable linkage with Sepharose beads, and have identified one with very high PgR affinity for further study. We first synthesized the epoxides of 17α-allyl nortestosterone, by analogy with the estradiol derivatization of Greene and Jensen. The relative affinity of these epoxides for PgR from T47D human breast cancer cells, however, was only around 5% that of R5020, and affinity beads prepared from them bound very little PgR. We then reacted appropriately protected 17α-ethynyl-nortestosterone with a series of diiodo alkanes, and found that 17α-(6'-iodohex-1'-ynyl)nortestosterone had an affinity of 22% relative to R5020, equal to the affinity of progesterone itself. Reaction with Thiopropyl-Sepharose 6B yielded hexynyl-nortestosterone-Sepharose beads with a ligand density of about 7 micromoles/ml beads. One-hundred μl of these beads adsorbed 71% of the PgR present in 1 ml ofcytosol from T47D cells. This adsorption was inhibited by 10 μM progesterone but not Cortisol, indicating the specificity of the binding. Comparisions with NADAC and Sterogel, other affinity beads used for PgR purification, show that the former takes up much less receptor, while the latter takes up and releases similar amounts of receptor but more extraneous protein, and is less stable. We therefore believe that hexynyl-nortestosterone-Sepharose, having a high density of a high affinity ligand, and having chemically and biochemically stable covalent bonds, should be a good reagent for affinity purification of PgR.     

MIB1 proliferation index in breast infiltrating carcinoma: comparison with other proliferative markers and association with new biological prognostic factors

AIMS: In breast invasive carcinoma our objectives were I) to compare cellular proliferation determined by MIB1 index with S-phase fraction (SPF) assessed by flow cytometry and with mitotic index, and II) to examine the association of MIB1 index with classical and with new biological prognostic factors [bcl-2, p53, c-erbB-2 and cathepsin D (CD)]. METHODS AND RESULTS: From 102 cases of breast invasive carcinoma, 5-microm thick serial sections were cut from formalin-fixed, paraffin-embedded tissue blocks, and processed for detection of CD, c-erbB-2, p53, bcl-2, Ki-67 antigen MIB-1 and estrogen receptors (ER) and progesterone receptors (PR). SPF was measured by flow cytometry in fresh-frozen tissue samples taken from the carcinoma in each patient. MIB1 index was correlated with SPF (rho=0.45, p<0.0001) and with mitotic index (rho=0.42, p<0.0001). The MIB-1 index was positively associated with the histological grade (p=0.001), tumor size (p=0.04) and the presence of metastases in axillary lymph nodes (p=0.01). MIB1 was associated directly with p53 (p=0.045) and inversely with bcl-2 (p=0.0002). The MIB-1 index was not statistically associated with c-erbB-2. There was a weak association between MIBI index and stromal cell CD. The median MIB1 index was higher in tumors with moderate to strong CD staining of stromal cell, but the difference did not reach statistical significance (p=0.09). CONCLUSIONS: MIB1 index correlates with well established methods for assessing tumor proliferation and with parameters of an aggressive phenotype of tumor. MIB1 index is an effective and readily accessible method for assessing tumor proliferation in breast carcinoma.     

Changes in receptor status after treatment with tamoxifen in endometrial cancer

Estrogen (ER) and progesterone receptor (PgR) status was determined in 41 women with operable endometrial cancer before and after administration of tamoxifen (TAM). The first sample was obtained by hysteroscopy to ensure a precise biopsy of neoplastic tissue; the second was done on the surgical specimen. PgR content was significantly increased after TAM treatment and this data was compared with the degree of tumor differentiation.     

Aromatase inhibitors: cellular and molecular effects

Marked cellular and molecular changes may occur in breast cancers following treatment of postmenopausal breast cancer patients with aromatase inhibitors. Neoadjuvant protocols, in which treatment is given with the primary tumour still within the breast, are particularly illuminating. In Edinburgh, we have shown that 3 months treatment with either anastrozole, exemestane or letrozole produces pathological responses in the majority of oestrogen receptor (ER)-rich tumours (39/59) as manifested by reduced cellularity/increased fibrosis. Changes in histological grading may also take place, most notably a reduction in mitotic figures. This probably reflects an influence on proliferation as most tumours (82%) show a marked decrease in the proliferation marker, Ki67. These effects are generally more dramatic than seen with tamoxifen given in the same setting. Differences between aromatase inhibitors and tamoxifen are also apparent in changes in steroid hormone expression. Thus, immuno-staining for progesterone receptor (PgR) is reduced in almost all cases by aromatase inhibitors, becoming undetectable in many. This contrasts with effects of tamoxifen in which the most common change on PgR is to increase expression. Changes in proliferation occur rapidly following the onset of exposure to aromatase inhibitors. Thus, neoadjuvant studies with letrozole in which tumour was sampled before and after 14 days and 3 months treatment show that decreased expression of Ki67 occur at 14 days and, in many cases, the effect is greater at 14 days than 3 months. These early changes precede evidence of clinical response but do not predict for it. However, this study design has allowed RNA analysis of sequential biopsies taken during the neoadjuvant therapy. Based on clustering techniques, it has been possible to subdivide tumours into groups showing distinct patterns of molecular changes. These changes in tumour gene expression may allow definition of tumour cohorts with differing sensitivity to aromatase inhibitors and permit early recognition of response and resistance.     

Cell proliferation in prostatic carcinoma: comparative analysis of Ki-67, MIB-1 and PCNA

Summary Antibodies to assess the proliferative index of tumours are being increasingly employed together with established markers for prognostic evaluation. This study set out to compare three cell proliferation markers, Ki-67, MIB-1 and PCNA, utilizing a semiquantitative method of assessment, in 20 human prostatic carcinomas. The streptavidin-biotin immunostaining system was used for the monoclonal antibodies MIB-1 and PCNA and an indirect immunoperoxidase assay for the monoclonal antibody Ki-67. Significant correlations were found between the expression of Ki-67 in frozen tissues and MIB-1 in formal saline-fixed wax-embedded tissues (p = 0.0003); between Ki-67 and PCNA expression in Bouin's-fixed tissues (p </ 0.0001); and MIB-1 (formalin-saline-fixed tissues) and PCNA (Bouin's-fixed tissues) (p </ 0.0001). A more intense nuclear staining pattern with less heterogeneity was observed for MIB-1 compared with PCNA, suggesting the antibody of choice, on formal saline-fixed tissues, is MIB-1, which closely correlated with Ki-67, a marker we have previously shown to be of prognostic value in prostatic carcinoma.     

RSF1 and Not Cyclin D1 Gene Amplification May Predict Lack of Benefit from Adjuvant Tamoxifen in High-Risk Pre-Menopausal Women in the MA.12 Randomized Clinical Trial

Most women with estrogen receptor expressing breast cancers receiving anti-estrogens such as tamoxifen may not need or benefit from them. Besides the estrogen receptor, there are no predictive biomarkers to help select breast cancer patients for tamoxifen treatment. CCND1 (cyclin D1) gene amplification is a putative candidate tamoxifen predictive biomarker. The RSF1 (remodeling and spacing factor 1) gene is frequently co-amplified with CCND1 on chromosome 11q. We validated the predictive value of these biomarkers in the MA.12 randomized study of adjuvant tamoxifen vs. placebo in high-risk premenopausal early breast cancer. Premenopausal women with node-positive/high-risk node-negative early breast cancer received standard adjuvant chemotherapy and then were randomized to tamoxifen (20 mg/day) or placebo for 5 yrs. Overall survival (OS) and relapse-free survival (RFS) were evaluated. Fluorescent in-situ hybridization was performed on a tissue microarray of 495 breast tumors (74% of patients) to measure CCND1 and RSF1 copy number. A multivariate Cox model to obtain hazard ratios (HR) adjusting for clinico-pathologic factors was used to assess the effect of these biomarkers on Os and RFS. 672 women were followed for a median of 8.4 years. We were able to measure the DNA copy number of CCND1 in 442 patients and RSF1 in 413 patients. CCND1 gene amplification was observed in 8.7% and RSF1 in 6.8% of these patients, preferentially in estrogen receptor-positive breast cancers. No statistically significant interaction with treatment was observed for either CCND1 or RSF1 amplification, although patients with high RSF1 copy number did not show benefit from adjuvant tamoxifen (HR = 1.11, interaction p = 0.09). Unlike CCND1 amplification, RSF1 amplification may predict for outcome in high-risk premenopausal breast cancer patients treated with adjuvant tamoxifen.     

Induction and inhibition of estradiol hydroxylase activities in MCF-7 human breast cancer cells in culture

The effects of estradiol, progesterone, and tamoxifen on the activity of estradiol 2- and 16 alpha-hydroxylases were studied in human breast cancer cell cultures using a radiometric assay. After 5 days' exposure to these compounds, incubations in the presence of either [2-3H]estradiol or [16 alpha-3H]estradiol as substrate were carried out. In MCF-7 cells, estradiol (10(-8) M), progesterone (10(-6) M) and tamoxifen (10(-6) M) significantly increased 16 alpha-hydroxylase activity (estradiol; 21% progesterone 10% to 32%; tamoxifen 21% to 31%; P less than 0.01). Synergistic effects were observed when the cells were successively exposed to tamoxifen and progesterone. Simultaneous treatment with tamoxifen plus estradiol or estradiol plus progesterone showed no change from estradiol alone. On the other hand, although estradiol had no direct effects on 2-hydroxylase activity, tamoxifen decreased this enzymatic activity significantly at 10(-6) M (23% to 37%). Progesterone acted synergistically to further decrease this reaction. Treatment with only progesterone caused an increase in 2-hydroxylation. In contrast, a subline of MCF-7 cells with low estrogen receptor levels showed only minimal enzyme-hormone responses. Likewise, treatment of the estrogen receptor-negative MDA-MB-231 human breast cancer cell line with these compounds showed no effects on either 2- or 16 alpha-hydroxylase activity. In the progesterone receptor-rich T47D cell line, estradiol decreased both activities while progesterone increased both.(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibition of estrogen receptor alpha expression and function in MCF-7 cells by kaempferol

Estrogens are mitogenic for estrogen receptor (ER)-positive breast cancer cells. Current treatment of ER-positive breast tumors is directed towards interruption of estrogen activity. We report that treatment of ER-positive breast cancer cells with kaempferol resulted in a time- and dose-dependent decrease in cell number. The concentration required to produce 50% growth inhibition at 48 h was approximately 35.0 and 70.0 microM for ER-positive and ER-negative breast cancer cells, respectively. For MCF-7 cells, a reduction in the ER-alpha mRNA equivalent to 50, 12, 10% of controls was observed 24 h after treatment with 17.5, 35.0, and 70.0 microM of kaempferol, respectively. Concomitantly, these treatments led to a 58, 80, and 85% decrease in ER-alpha protein. The inhibitory effect of kaempferol on ER-alpha levels was seen as early as 6 h post-treatment. Kaempferol treatment also led in a dose-dependent decrease in the expression of progesterone receptor (PgR), cyclin D1, and insulin receptor substrate 1 (IRS-1). Immunocytochemical study revealed that ER-alpha protein in kaempferol-treated MCF-7 cells formed an aggregation in the nuclei. Kaempferol also induced degradation of ER-alpha by a different pathway than that were observed for the antiestrogen ICI 182,780 and estradiol. Estradiol-induced MCF-7 cell proliferation and expression of the estrogen-responsive-element-reporter gene activity were abolished in cells co-treated with kaempferol. These findings suggest that modulation of ER-alpha expression and function by kaempferol may be, in part, responsible for its anti-proliferative effects seen in in vitro.     

Estrogen and progesterone receptors in colorectal cancer and surrounding mucosa

In this prospective study we have quantified by means of ELISA-methods the cytosolic content of estrogen (ER) and progesterone receptors (PgR) in tumoral tissue and paired normal mucosa from 163 patients with resectable colorectal cancer. Survival analysis was performed in a subgroup of 120 patients and the mean follow-up period was 24.9 months. The cutoff for ER and PgR levels was set at 1 fmol/mg protein. On the basis of this cutoff 20.9% of the cancers were ER positive and 25.8% were PgR positive; normal adjacent tissue presented ER in 18.4% and PgR in 24.5%. Our results did not show any significant correlation between ER and PgR levels in neoplastic tissues. Howewer, a correlation was found in normal mucosa samples (p=0.02). Statistical analysis showed that there was no correlation between tumor ER and PgR content and patient age or sex, tumor location, Dukes' stage, histological differentiation, DNA ploidy status and S-phase fraction. Furthermore, the results did not show any statistical differences in relapse-free and overall survival curves calculated for patients classified according to the hormone receptor content of their tumors. ER and PgR were detected at low levels in normal and neoplastic colorectal tissues without any significant relationship to either clinicopathological tumor characteristics or patient outcome. Their possible role in colorectal cancer remains to be elucidated.