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Immunocytochemical detection of progesterone receptor by monoclonal KD-68 antibody in operable breast cancer: correlations with biochemical assay, pathological features and cell proliferative rate.

A new immunocytochemical assay (ICA) for progesterone receptor (PgR), employing the rat monoclonal KD-68 antibody and a sensitive peroxidase-anti-peroxidase (PAP) technique as the displaying system, was performed in 129 human breast cancer specimens. PgR-ICA staining was almost all electively located in neoplastic cell nuclei with a substantial heterogeneity in distribution and intensity. To study the basic relationship of the results of the ICA method with the biochemical dextran-coated charcoal (DCC) assay we compared, in all the same specimens, the antibody nuclear staining with the PgR positivity by DCC (cut-off value of 10 fmol/mg of protein). We found an overall agreement of 77% between the two methods and a PgR-ICA sensitivity of 83% and a specificity of 72%, assuming that biochemical PgR is truth. PgR-ICA false-negative results were only nine out of 53 (17%); and false-positive were 21 out of 76 (28%). Using both methods no significant association was observed between PgR positivity with menopausal status, histological type, tumor size and lymph node status. The correlations between PgR expression and cell kinetics were assessed by an immunocytochemical method employing the monoclonal Ki-67 antibody. While a significant negative relationship was found between high Ki-67 score and PgR-ICA positivity (P less than 0.01) no correlation was found with DCC positivity. The present results demonstrate that ICA is a practical, reliable and inexpensive method with a good correlation to the conventional biochemical assay to determine the PgR status. Moreover, ICA recognizes PgR expression at the single cell level, thus providing additional information to the quantitative DCC assay that should improve the prognostic evaluation and the prediction of responsiveness to endocrine therapy in breast cancer.

Adult↗

Molecular identification, expression and prognostic role of estrogen- and progesterone receptors in head and neck cancer.

The aims of this study were to assess the sex hormone receptor status of head and neck (HNC) cancers. Frozen surgical samples (n = 67) of HNC patients were analyzed. Protein expression of estrogen receptor (ER)alpha, ERbeta and progesterone receptor (PgR) of tumor cells was determined by immunocytochemistry. Data were confirmed at mRNA level by nested-PCR and sequencing. ER and PgR expressions confirmed by PCR analysis were frequent in HNC: 50.7 and 49.3% respectively. Concerning the ER isoforms, ERalpha expression was predominant over ERbeta in both of oral cavity- as well as laryngeal/hypopharyngeal (LH) cancers. The delta3 splice variant of ERalpha was detected at low frequency, while the delta5 splice variant of ERbeta was frequent in HNC. The incidence of functional receptor expression (coexpression of ER and PgR) was relatively frequent also in HNC (27/67, 40.3%) which was independent of the anatomical location of the tumor. Sex hormone receptor expressions did not affect survival of HNC patients, however, in the LH cancer subgroup ER expression was associated with a trend of shortened survival (p = 0.0636, Mantel-Cox generalized savage). ERalpha,beta and PgR expressions are frequent in HNC and may affect the prognosis of the disease, at least in case of LH cancers.

Adult↗

Proliferation, steroid receptors and clinical/pathological response in breast cancer treated with letrozole.

Sixty-three postmenopausal women with large primary breast cancers were treated with neoadjuvant letrozole (2.5 mg daily) for 3 months. Tumour samples were taken at diagnosis and after 10-14 days and 3 months treatment. Immunohistochemical staining for Ki67, oestrogen receptor (ER) and progesterone receptor (PgR) was performed and related to clinical (ClinR) and pathological responses (PathR) after 3 months treatment. ClinR was observed in 48 of 63 cases (76.2%) and PathR in 47 of 62 (75.8%). Pretreatment Ki67 scores were similar in responders (R) and non-responders (NR). Highly significant Ki67 decreases occurred in all tumour subgroups at 10-14 days (P<0.005). A significant difference in Ki67 scores at 10-14 days (P<0.007) was found between PathR and PathNR but not between ClinR and ClinNR. At 3 months, decreases from pretreatment Ki67 scores were highly significant in all tumour subgroups irrespective of response status. However, whereas Ki67 scores were significantly different between pathological R and NR (P = 0.009), the corresponding comparison of ClinR status was not. Significant decreases between 10-14 days and 3 months were found only in ClinR and PathR (P = 0.02 and 0.045, respectively). Treatment significantly reduced PgR expression at 14 days and 3 months (both P<0.0001), but the level of changes was not different between response status groups. In summary, letrozole produces rapid and profound decreases in expression of Ki67 and PgR but changes do not always correlate with clinical and pathological responses.

Aged↗

Demonstration of estrogen receptors and of estrogen responsiveness in the HKT-1097 cell line derived from diethylstilbestrol-induced kidney tumors.

This study was undertaken in order to examine the estrogen sensitivity of HKT-1097, an established cell line recently derived from diethylstilbestrol (DES)-induced kidney tumors in Syrian hamsters. Estrogen receptor (ER) level in HKT-1097, determined by enzyme-linked immunoassay, was 67 fmol/mg protein, i.e., a value approx. 30% lower than that found in Syrian hamster kidney tumors. ER immunostaining in cells fixed with Carnoy's mixture, as well as ER demonstration by Western blotting, suggested DES-induced nuclear translocation or stabilization of the receptor within the nucleus. Kinetic parameters of estrogen binding to ER in HKT-1097 cells were 8.4 x 10(-11) M and 60.8 fmol/mg protein for Kd and Bmax, respectively. The Kd of estrogen binding to ER in HKT-1097 was close to that evaluated for the receptor in breast cancer-derived MCF-7 cell line, whereas the Bmax value was approx. seven times lower in HKT-1097 as compared to MCF-7. In HKT-1097 cells, antiestrogens ICI 182,780 and RU 58,668 induced ER downregulation and competed with estrogen binding to the receptor. As demonstrated by Western blot analysis, DES exposure led to an increased expression of progesterone receptor (PgR) in HKT-1097 cells. Addition of DES to estrogen-free medium produced a stimulation of growth in both HKT-1097 and MCF-7 cells, but the mitogenic effect was less marked for HKT-1097. Despite the fact that ICI 182,780 and RU 58,668 clearly interact with HKT-1097 cell ER, they appeared unable to suppress DES-induced stimulation of growth and increase of PgR expression.

Animals↗

Prenylflavonoids as nonsteroidal phytoestrogens and related structure-activity relationships.

In the search for estrogen receptor (ER) modulators, a series of prenylflavonoids were found to be widely distributed amongst tonic herbal medicines and to possess estrogen-like activity in MCF-7/BOS cells, as evaluated by an estrogen-screening assay. Cell-cycle analysis revealed that the stimulatory effects of these compounds toward cell proliferation were elicited at the G1-S checkpoint and could significantly increase the S-phase population of MCF-7 cells under hormone-free conditions. ER-responsive gene (PS2, PgR) and protein (PgR) expression was also detected; mRNA and protein-expression levels for PS2 and PgR were up-regulated by the compounds in a dose-dependent manner. These effects could be inhibited by the pure ER antagonist ICI 182,780 ((7alpha-[9-{4,4,5,5,5-pentafluoropentyl}sulfinyl]nonyl)estra-1,3,5(10)-triene-3,17beta-diol). It was therefore concluded that the estrogen-like effects of these prenylflavonoids were mediated primarily through ERs. Furthermore, to explore the structure-activity relationship based on the estrogen receptor and detailed molecular mechanisms among the prenylflavonoids, protein-ligand docking simulations were carried out by using the DS-MODELING software package. The binding affinity of each prenylflavonoid toward ERalpha was scored, and the receptor-ligand interaction was also analyzed to provide the simulation characteristics of virtual molecular recognition mechanisms.

Base Sequence↗

Measurement of steroid hormone receptors in breast cancer patients on tamoxifen.

Estrogen (ER) and progesterone receptor (PgR) positive breast tumors often respond to tamoxifen, but ultimately progress as they become tamoxifen resistant. An accurate assessment of receptor status in specimens from tamoxifen-resistant patients could help to understand potential mechanisms of resistance and to predict response to second line hormonal therapies. However, since tamoxifen itself can affect ER and PgR determinations, assay results can be misleading. We measured ER and PgR by both ligand binding (LBA) and immunohistochemical (IHC) assays in 34 tumors from patients on tamoxifen, 30 of whom were displaying resistance to the drug. These tumors were classified into several receptor phenotypes. Eleven patients, 8 of whom were clearly progressing, expressed both receptors while on tamoxifen. ER was significantly less often negative when measured by IHC, suggesting that ER status by LBA was falsely negative in this group due to receptor occupancy by tamoxifen. Six patients had no detectable ER by LBA or IHC but still expressed PgR. The presence of PgR suggests that ER could still be functional, though undetectable, in these tumors, or that PgR is constitutively expressed by them. Finally, 12 patients were ER and PgR-negative by both assays, suggesting hormonal independence as the mechanism for resistance in this group. In a subset of patients with receptor assays both prior to tamoxifen and at the time of progression while taking the drug, we found that most ER-positive tumors converted to an apparent ER-negative status when assayed by LBA, while PgR status frequently remained unchanged. The continued expression of ER and/or PgR in many patients with tumor progression on tamoxifen indicates that mechanisms for resistance other than receptor loss are common in breast cancer.

Adult↗

Clinical impact of detection of loss of heterozygosity of BRCA1 and BRCA2 markers in sporadic breast cancer.

The development of familial and sporadic breast cancer is based on genetic alterations of tumour-suppressor genes, for which loss of heterozygosity (LOH) is one mechanism of gene inactivation. To investigate LOH of BRCA1 (17q21) and BRCA2 (13-q12-13) in sporadic breast cancer, polymerase chain reaction (PCR)-based fluorescent DNA technology for detection of microsatellite polymorphisms was applied. A total of 137 breast cancer and 15 benign breast specimens with matched normal tissue were examined. Fluorescent-labelled PCR products were analysed in an automated DNA sequencer (ALFTM Pharmacia). Losses at both loci were correlated with different histological types, age, tumour size, lymph node status, grading and steroid hormone receptor expression, [SHR: oestrogen receptor (ER), progesterone receptor (PgR)]. For BRCA1 (D17S855, THRA1, D17S579) losses could be detected in invasive ductal carcinoma (IDC; n = 108) in 32-38%, invasive lobular carcinoma (ILC; n = 19) in 21-42% depending on the marker applied, but not in benign breast tumours (n = 15). Losses of BRCA1 markers correlated with larger tumour size, higher grade, and PgR expression. For BRCA2 (D13S260, D13S267, D13S171) losses could be detected in 108 IDCs in 30-38%, in 19 ILCs in 17-39% depending on the marker applied, but not in benign breast tumours. Losses of BRCA2 markers correlated only with higher grade. Microsatellite analyses combined with detection of fluorescent-labelled PCR products by an automated laser DNA sequencer can be used for routine determination of LOH. In sporadic breast cancer, LOH of BRCA1 of BRCA2 does not add decisive prognostic value as stated for familial breast cancer.

Age Factors↗

Nepalese breast cancer in relation to reproductive factors: comparison between Nepalese and Japanese cases.

The characteristics of Nepalese breast cancer in relation to reproductive factors have not been studied. One hundred and nine Nepalese breast cancer patients were compared with 108 Japanese breast cancer patients and the expression of estrogen (ER) and progesterone receptor (PgR) was evaluated immunohistochemically in 27 Nepalese breast cancer cases. In the Nepalese cases, the age at menarche was significantly older (14.1 vs 13.3 years), while the age at menopause was similar (49.0 vs 49.9 years). The mean age at first full-term pregnancy was significantly lower (20.6 vs 26.6 years), the average number of children was significantly larger (3.1 vs 2.1) and the cumulative duration of lactation was significantly longer (26.9 vs 17.1 months) in the Nepalese cases. In both groups, approximately 60% of breast cancer was premenopausal. The average age of Nepalese breast cancer patients, particularly premenopausal breast cancer patients, was significantly lower (38.6 vs 44.9 years). ER and PgR expression was 11% and 15%, respectively, in Nepalese breast cancer. Nepalese breast cancers were in an advanced stage when discovered. Nepalese breast cancer cases, particularly premenopausal breast cancer patients, were seen at a relatively young age with late menarche, early first full-term pregnancy, long duration of lactation and a large number of children, when compared with Japanese cases. Breast cancer in Nepal may involve mechanisms independent of estrogen exposure.

Adult↗

Nuclear expression of YB-1 protein correlates with P-glycoprotein expression in human breast carcinoma.

Drug resistance is a common clinical problem in cancer treatment. The overexpression of P-glycoprotein appears to be closely associated with multi-drug resistance to anticancer agents. YB-1 binds to the Y-box in the promoter region of MDR1, which encodes P-glycoprotein. We evaluated the correlation between nuclear YB-1 and P-glycoprotein expression and other molecules, such as hormonal receptors, angiogenic factors, immune factors, and methalloprotease in 63 human breast cancers. Nuclear YB-1 expression had a significant correlation with P-glycoprotein and PgR expression, and also with CD68 grade, concerning accumulation of tumor associated macrophages. This series did not demonstrate P-glycoprotein and nuclear YB-1 expression might be one of the useful prognostic marker of breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Adenocarcinoma of the cervix. Expression and clinical significance of estrogen and progesterone receptors.

BACKGROUND: Although hormone receptor status is an important prognostic indicator in adenocarcinoma of the breast and the endometrium, few studies have investigated the expression and clinical significance of estrogen receptor (ER) and progesterone receptor (PgR) in adenocarcinoma of the cervix. METHODS: ER and PgR expression were determined using an immunohistochemical method in 84 cervical adenocarcinomas. Clinical features and outcome were determined by chart review. RESULTS: ER was identified in 17 of the 84 cases (20%). ER positivity was most frequently detected in mucinous adenocarcinoma of the endocervical type (in 11 of 48 cases) and endometrioid adenocarcinoma (in 4 of 10 cases). PgR was identified in 23 of the 84 cases (27%). PgR positivity was also most frequently detected in mucinous adenocarcinoma of the endocervical type (in 15 of 48 cases) and endometrioid adenocarcinoma (in 6 of 10 cases). Mucinous adenocarcinoma of the intestinal type (five cases), glassy cell carcinoma (two cases), and clear cell adenocarcinoma (two cases) were uniformly negative for both ER and PgR. No association was detected between International Federation of Gynecology and Obstetrics stage and receptor status, but there was a somewhat lower frequency of ER positivity in poorly differentiated tumors (P = 0.07). No association was detected between PgR status and disease free survival. Similarly, no association between ER status and overall survival was observed. Although ER positive tumors may be associated with longer disease free survival than ER negative tumors, this difference did not reach statistical significance in this study (P = 0.06). CONCLUSIONS: ER and PgR positivity were found in 20% and 27%, respectively, of primary cervical adenocarcinomas. However, receptor status was not significantly associated with either overall survival or disease free survival.

Adenocarcinoma↗

Oestrogen and progesterone receptor expression influences DNA ploidy and the proliferation potential of breast cancer cells.

The influence of oestrogen (ER) and progesterone (PgR) receptor has not been investigated in relation to DNA ploidy and cell proliferation. Here we have investigated a series of 46 breast cancer fine-needle aspirates in order to define the prognostic value of ER/PgR and possible correlations between DNA ploidy, size of the S-phase fraction (SPF) and cell cycle distribution features measured by image cytometry (ICM) and ER/PgR status of the primary tumours. The breast cancers were grouped into ER+/PgR+, ER+/PgR- and ER-/PgR-. Inter-group comparisons were made of DNA ploidy, SPF and the pattern of cell cycle distribution defined by the G0G1/G2M ratio in order to determine the influence of ER and PgR expression on the respective cell features. Our studies suggest that ER and PgR exert differential effects on the cell features examined. This study also analysed the possibility of predicting nodal involvement and 5-year disease-free survival by combining ER/PgR status with DNA ploidy, SPF and G0G1/G2M ratios. A high degree of accuracy was achieved for predicting both nodal involvement and 5-year disease-free survival. These findings suggest that a combination of ER/PgR status with DNA ploidy, SPF and cell cycle distribution provide a powerful marker for disease prognosis.

Breast Neoplasms↗

EGFR activity in HER-2 over-expressing metastatic breast cancer: evidence for simultaneous phosphorylation of Her-2/neu and EGFR.

Her-2/neu overexpression is an important prognostic parameter in breast cancer patients and has become a response predictor for trastuzumab treatment. Nevertheless, while trastuzumab is highly effective in many Her-2/neu overexpressing tumors, some do not respond. The reason for the differential effect is unknown, but it has been hypothesized that the complex interactions between Her-2/neu and other members of the EGFR family are involved in trastuzumab resistance. We have analyzed the protein expression of Her-2/neu, EGFR, and their activated forms, ptyr-1248 Her-2/neu, ptyr-845 EGFR and ptyr-1173 EGFR, in 57 Her-2/neu overexpressing breast tumors and investigated potential correlations between the receptors. By performing immunohistochemistry on paraffin-embedded tissue sections, we found that ptyr-845 EGFR was significantly co-expressed with Her-2/neu and ptyr-1248 Her-2/neu (p=0.043 and p=0.040, respectively), while ptyr-1173 EGFR was only correlated to Her-2/neu expression (p=0.042). Interestingly, EGFR and its activated forms were all significantly inversely correlated with PgR expression (p=0.011, p=0.033 and p=0.032, respectively), and ptyr-845 EGFR was also inversely correlated with ER expression (p=0.008). While we have previously shown that serum levels of the extracellular component of Her-2/neu are associated with tumoral ptyr-1248 Her-2/neu expression, we did not find a similar relationship between serum EGFR and intratumoral total/activated EGFR. We did, however, observe significantly higher levels of serum EGFR in women with 3+ overexpression of HER-2/neu (p=0.047). Taken together, we have demonstrated the activation pattern of EGFR and Her-2/neu in Her-2/neu overexpressing breast cancer. We suggest that EGFR inhibition might enhance the efficacy of trastuzumab by preventing cross-phosphorylation.

Adult↗

Estrogen receptor expression of benign breast epithelium and its association with breast cancer.

We conducted a case-control study of estrogen receptor (ER) and progesterone receptor (PgR) expression in benign breast epithelium from 120 women (51 breast cancer cases and 69 benign disease controls) who underwent breast operations at University Hospital, Syracuse, New York. Benign samples were obtained and processed immunohistochemically for ER and PgR (Abbott, Chicago, IL). Receptor positivity was defined as any nuclear immunostaining. Proportionately more cases than controls were ER positive (84% versus 57%); PgR positivity was similar in cases and controls (86%). Logistic regression yielded an adjusted odds ratio of 6.5 for breast cancer among ER-positive women (95% confidence interval of 1.5 and 27.4); odds ratio of PgR positivity was 0.3 (95% confidence interval of 0.1 and 1.9). Adjustment for known risk factors for breast cancer did not change the odds ratio. ER-positive breast epithelium needs evaluation as a possible risk marker for breast cancer.

Adult↗

Human chorionic gonadotrophin-beta transcripts correlate with progesterone receptor values in breast carcinomas.

The pathophysiological role for the expression of human chorionic gonadotrophin (hCG) in malignant neoplasms is currently speculative. We investigated the overall expression of genes hCG-beta 5, 3, 8 and 7 in breast carcinoma (n=214), fibroadenoma (n=37) and macromastia (n=10) by quantitative reverse transcriptase-PCR. Eighty (37.4%) of the breast cancer samples revealed positive hCG-beta mRNA expression and the mean value was 67. 9 copies per 200 ng total RNA (range: 0-1743; 95% confidence interval (CI) for mean: 44-92). Fibroadenomas had more frequently detected (56.8%) and greater hCG-beta copy numbers (mean 86.9; range: 0-845; 95% CI for mean: 35-138). Macromastia probes yielded no positive hCG-beta mRNA. The hCG-beta mRNA expression was significantly different in the three histological subgroups (P=0. 006). Among breast carcinomas, a positive correlation was detected between hCG-beta mRNA copy numbers and progesterone receptor (PgR) values (P<0.001). No significant differences were seen regarding disease-free (P=0.87) and overall survival (P=0.20) depending on hCG-beta mRNA status. Finally, our findings do not support a role for hCG-beta in malignant transformation of human breast cells and indicate a possible involvement of hCG-beta in benign breast disease. The relationship with PgR expression may suggest that progestins regulate the expression of hCG in breast epithelial cells.

Adult↗

Cellular receptors for sex steroids in human pituitary adenomas.

Cellular receptors for sex steroids (SSRs) were studied in an unselected series of 55 human pituitary tumors. Cytosolic receptors for estrogen (ERcs) and progesterone (PgRcs) were determined in all cases and cytosolic androgen receptors (ARcs) in 47 cases. Nuclear receptors (ERns, PgRns, ARns) were also studied in 33 cases. ERs and PgRs were determined by an ELISA and ARs by [3H]methyltrienolone binding. Where both cytosolic and nuclear receptors were studied (n = 33), ERs, PgRs and ARs were found in at least one subcellular fraction in 66.7, 60.6 and 81.8% of cases respectively, ERs and ARs being mainly recovered from the cytosol and PgRs from the nucleus. No linear correlation was found between pre-operative plasma steroid hormones and their specific cellular receptors. Nonetheless, the differential expression of SSRs according to sex and gonadal status at the time of surgery strongly supports their regulation by the steroid environment in vivo: PgRcs were more frequent in tumors found in women (41.4 vs 15.4%, P < 0.05), whereas a high expression of ERcs and ARcs (> 15 fmol/mg protein) was more common in tumors found in men (34.5 vs 10.3%, P < 0.05 and 54.5 vs 24.0% respectively). PgRs were positively correlated with ERns, indicating the possibility of estrogen priming of their expression, and negatively correlated with ARs in nuclear fractions. SSRs appeared to be widely distributed among pituitary tumors, although, compared with other hormone-secreting groups, prolactinomas displayed a higher ERc expression (34.8 +/- 11.3 vs 4.8 +/- 5.1 fmol/mg protein, P = 0.007) and gonadotroph cell adenomas lower ARc values (1.3 +/- 0.8 vs 38.2 +/- 10.6 fmol/mg protein, P = 0.048). Microadenomas were characterized by a higher PgR expression than macroadenomas, whereas hemorrhagic (macro)adenomas were characterized by a high ER expression (> 90%). The present results indicate that most pituitary tumors are targets for sex steroids, SSR expression being partially triggered by the steroid environment itself. Possible physiopathological and therapeutic implications of these findings are discussed.

Adenoma↗

Estrogen receptor mutations and changes in estrogen receptor and progesterone receptor protein expression in metastatic or recurrent breast cancer.

To investigate the frequency of estrogen receptor (ER) gene mutation in metastatic or recurrent breast cancer, metastatic lymph nodes or recurrent breast cancer tissue from 35 patients with ER-positive primary tumors were screened for mutations in the hormone-binding domain of the ER gene by sequence analysis. Four missense mutations, Val316Ile, Gly344Val, Ala430Val and Gly494Val, were identified in these lesions. Second, to clarify whether there is any disparity in hormone receptor status between primary and metastatic or recurrent tumors, we immunohistochemically studied 117 specimens including the above 35 specimens obtained from metastatic or recurrent breast cancer patients using monoclonal anti-ER and progesterone receptor (PgR) antibodies. Although hormone receptor status, especially ER, was highly maintained through disease progression, negative change in PgR expression at relapse (33%) was identified more frequently than in metastatic lymph nodes (6.7%). Therefore, it was suggested that development of PgR-negative phenotype might correlate with disease progression in some breast cancer patients. These results suggest that ER mutations in metastatic or recurrent breast cancer may be more frequent than in primary lesions, irrespective of high maintenance of ER protein expression through disease progression.

Breast Neoplasms↗

Immunohistochemical evaluation of hormone receptor status for predicting response to endocrine therapy in metastatic breast cancer.

BACKGROUND: The importance of establishing hormone receptor status of tumors for the treatment of women with hormone receptor-positive breast cancer has been emphasized, however, there is no general agreement as to how immunohistochemical assays should be evaluated. It is critical to evaluate hormone receptor status when considering response to endocrine therapy. METHODS: Estrogen receptor (ER) and progesterone receptor (PgR) expression was examined by immunohistochemistry using Allred's score for primary breast tumors from 75 metastatic breast cancer patients who received first-line treatment with endocrine therapy (56 patients received tamoxifen, 11 patients received aromatase inhibitors, and 8 patients received LH-RH agonist or other endocrine reagents) on relapse. Correlation between hormone receptor status and response to endocrine therapy as well as post-relapse survival was analyzed. RESULTS: The most significant correlation between positive ER expression and response to any endocrine therapy (p = 0.011) or tamoxifen only (p = 0.030) occurred when the cutoff score was set at 10%. When the evaluation was based on Allred's score (TS), a cutoff point of TS>or=4 showed a more significant association between positive ER expression and response to all kinds of endocrine therapy (p = 0.020) or tamoxifen only (p = 0.047). When evaluated at a cutoff point of 1% positive cells, there were fifteen patients with both ER- and PgR-negative tumors, and three patients (20.0%) responded to the therapy. Patients with 1% or more ER or PgR positive cells had better survival after relapse (p = 0.0005 and p = 0.0008, respectively). CONCLUSIONS: The proportion score alone might be enough to predict hormone responsiveness and post-relapse survival in metastatic breast cancer. The cutoff might be set low, for example 1%, especially for metastatic disease.

Antineoplastic Agents, Hormonal↗

Cell-transforming activity and estrogenicity of bisphenol-A and 4 of its analogs in mammalian cells.

Estrogenicity is an important mechanism in hormonal carcinogenesis but not sufficient to explain the carcinogenic activity of all estrogens. Additional mechanisms, related to genetic alterations, in conjunction with estrogenicity mediated through the estrogen receptor, have been suggested. An environmental estrogen bisphenol-A (BP-A) and its analogs are widespread in our living environment. Because of the potential for human exposure, the possible relationship between carcinogenicity and estrogenicity of these bisphenols was studied using mammalian cells. We quantitatively compared the cell-transforming activity of BP-A and 4 of its analogs (BP-2, BP-3, BP-4 and BP-5) in Syrian hamster embryo (SHE) cells lacking estrogen-receptor expression. The transforming activity determined by the morphological transformation frequencies in SHE cells treated with the bisphenols ranked: BP-4 > BP-5 > BP-3 > BP-A > BP-2. We also compared the estrogenicity of the 5 bisphenols in MCF7 human breast cancer cells as determined by cell proliferation or progesterone receptor (PgR) expression assayed by RT-PCR. When MCF7 cells were treated with the bisphenols, the proliferative potency ranked: BP-A > BP-5 > BP-4 > BP-3 = BP-2. The level of mRNA for PgR in cells treated with the bisphenols was BP-A > BP-5 > BP-4 > BP-3 > BP-2. These indicate that the transforming activity does not correlate with the estrogenicity of the bisphenols, except for BP-2 that has the weakest activity at the both endpoints. In addition, our results suggest that bisphenols with few, if any, transforming and estrogenic activities could be altered by a modification of the chemical structure. Published 2001 Wiley-Liss, Inc.

Animals↗