A Double-Labeling Assay for Simultaneous Estimation and Characterization of Estrogen and Progesterone Receptors using Radioiodinated Estradiol and Tritiated Org 2058

Estrogen (ER) and progesterone receptors (PgR) appear to be a prerequisite to elicit a biologic response by a hormone-target organ. Current methodologies for analysis of these proteins (e.g., dextran-coated charcoal, DCC) in single-label assay (SLA) require relatively large amounts of tissue material, time and laboriousness. Therefore, we have developed for breast cancer tissue an improved dual-label assay (DLA) for simultaneous titration (by DCC) and/or characterization (by sedimentation properties) of ER and PgR on the same sample, using 125I-E2 and 3H-Org 2058 as tracers. The interaction of 125I-E2 with ER and plasma proteins in comparison to 3H-E2 was studied in terms of specificity, time course, affinity binding and sedimentation pattern. 125I-E2 bound the same molecular forms displayed by 3H-E2 (9 and 3S) but with lower titers (about 1.3-fold), irrespective of the technique used, and did not bind to sex hormone-binding globulin. Simultaneous detection of 125I and 3H was achieved by use of a gamma counter plus a beta counter sequentially. ER and PgR titrations with DCC in DLA were in good agreement with those obtained with SLA, in terms of titers and Ka values. An analogous result was obtained with sucrose density gradient (SDG) analysis. Both the DLA methods were highly reproducible (CV < 8.0 %). Between the rotors available for SDG, the vertical one was preferable because of the larger number of samples processed and of less purturbation of sedimenting receptor molecules. Furthermore, a biochemical application of the method is described. In conclusion, the DLA procedure, by simplifying ER and PgR estimation, makes it possible to study, even on small tumor biopsies, the molecular properties of these proteins in relation to the clinical response of the disease.

Clinical Data and Estradiol Receptor Evaluation in Breast Cancer Biopsies

To determine the correlation between the response to the estradiol receptor test and some fundamental properties of the tumor and the host, a study was conducted on 337 patients. Primary carcinomas, including lobular carcinomas, and recurrences or metastases are characterized by similar frequencies of response to the estradiol receptor test (68% positive, 26% negative and 6% borderline), while normal breast tissue is characterized by a higher frequency of negative results (3% positive, 71% negative and 26% borderline). Postmenopausal patients show a shift of estradiol receptor levels towards higher values with respect to premenopausal patients. Contemporaneously, an increase in estradiol receptor concentrations with patient age is observed. The clinical stage appears to influence estradiol receptor content only in postmenopausal patients, for whom an increase in the tumor size is accompanied by a decrease in the estradiol receptor levels. The apparent association constant of the receptors assumes values ranging from 1.5 to about 300 × 10′ Mr’ and does not appear to be related to either the type of tumor tissue or to the clinical stage of the tumor, age, or menopausal status of the patient.

Detection of the 170 kDa P-Glycoprotein in Neoplastic and Normal Tissues

A membrane purification procedure and an immunoblotting assay have been designed to allow screening of human solid tumors for overexpression of the GP170 glycoprotein without employing a disaggregation method to obtain cell suspensions. The electrophoresed membrane proteins were probed, after Western Blotting, with the C219 monoclonal antibody and iodinated Protein A. The labeling intensity of the bands on the autoradioimmunoblots were quantified by densitometry. To test for the presence of GP170, we used membranes from the UV 2237 fibrosarcoma line and its adriamycin-resistant variant ADMR, grown in vitro or as solid tumor in mice. Membranes of human normal and tumor tissues obtained from previously untreated patients were also tested. An immunoreaction was observed in the adriamycin-resistant UV 2237 lines grown in vitro or in vivo. Quantitatively, the binding of the resistant cell line grown in vitro was higher than that observed in cells grown in mice. Bands in the GP 170 region were observed in 4/7 normal and in 7/7 tumor colon tissues and in the normal medulla from 2 patients with cancer of the renal cortex. No reaction could be found in samples from normal tissue, primary tumor or nodal metastasis from 7 patients with breast cancer.

Distribution and Chemotherapeutic Activity of Daunomycin and Adriamycin in Spontaneous Mammary Carcinoma of Mice

The distribution of tritiaded daunomycin and adriamycin have been studied in inbred C3H mice hearing spontaneous mammary carcinoma. It was found that adriamycin administration results in higher blood and tissue levels than daunomycin and that significant levels may be maintained in the tumor as much as a week after 3 injections of adriamycin 2.5 mg/kg at 12-intervals. Tumor hearing animals were treated with daunomycin or adriamycin daily or on alternate days. Daunomycin proved to be active only when administered daily, while adriamycin activity is marked even if administered every other day. Adriamycin activity is particularly marked if administered according to an intermittent schedule (weekly cycle of 3 injections every 12 h); on this schedule results the toxicity, as determined from weight loss and survival time of treated animals, is also somewhat lower.

Correlation between Clinical Response to Bilateral Oophorectomy, Estrogen Receptors and Urinary Androgen Excretion in 49 Patients with Advanced Breast Cancer

The aim of this study was to find out if it is possible to predict the clinical response to bilateral oophorectomy in premenopausal patients with advanced breast cancer. Two methods of determination were used before oophorectomy: 1) the presence of estrogen receptors in the tumor tissue; 2) the urinary concentration of androgens. The clinical response to oophorectomy was evaluated after a six-month follow-up. Determinations carried out on 49 patients showed that a significant correlation exists between clinical response to oophorectomy and androgenic activity alone or in combination with estrogen receptors when both tests give concordant results.

Variations in Estrogen and Progesterone Receptor Content in Premenopausal Breast Cancer Patients Throughout the Menstrual Cycle

Estrogen (ER) and progesterone (PgR) receptor content was assayed in 290 premenopausal women with primary breast cancer, in order to investigate the influence of endogenous hormones on cytoplasmic receptor concentrations throughout the menstrual cycle, subdivided into four phases of ovarian function (early and late follicular phase, early and late luteal phase). Of the total population, 231 (79.7 %) patients were ER positive and 59 (20.3 %) were ER negative; 220 (75.9 %) were PgR positive and 70 (24.1 %) were PgR negative. The percentages of positive cases were almost constant in each phase. No significant difference in mean values of ER concentration was noted throughout the cycle. Instead, the PgR concentration significantly increased from the first to the third phase (P = 0.02) and decreased from the third to the fourth phase (P = 0.01). Our results suggest that ER- and PgR- cases are homogeneously distributed and not influenced by the phase of the cycle. Moreover, they suggest that PgR measurement in the luteal phase, rather than in other phases, prevents the occurrence of false low PgR levels and, at the same time, improves its prognostic significance and response rate to endocrine therapy.

Distribution of Estrogen and Progesterone Receptors in Primary Tumor and Lymph Nodes in Individual Patients with Breast Cancer

Primary breast cancer tissue and lymph nodes were obtained from 48 patients. Estrogen receptors (ER) and progesterone receptors (PgR) were determined by a dextran-coated charcoal assay. ER were present in 72.9 % of the primary tumors and in 62.4 % of the malignant lymph nodes, whereas PgR were present in 73.0 % and 50.0 % of the cases, respectively. The primary tumor and the corresponding malignant lymph nodes showed an identical ER and PgR status, i.e., both tumor sites were receptor positive or both receptor negative in 89.6 % and 77.1 %, respectively. However, 10.4 % of the patients had ER-positive tumors but ER-negative lymph nodes and 22.9 % had PgR-positive primaries with PgR-negative lymph nodes. No receptor-positive lymph nodes showed a combination with receptor-negative primary tumor. This preliminary data shows that receptor-positive malignant lymph nodes mostly display the same receptor status as the corresponding primary tumor, whereas receptor-negative lymph nodes may have a receptor-positive primary tumor.

Prognostic Significance of Progesterone Receptors Alone or in Association with Estrogen Receptors in Human Breast Cancer

Estrogen (ER) and progesterone (PgR) receptors were measured simultaneously in 1144 consecutive breast cancer patients to determine the distribution of patients according to receptor and menopausal status when receptor occurrence rates were considered. The prognostic signicance of PgR, either alone or in association with ER, was studied on 187 consecutive breast cancer patients treated only by radical mastectomy. All the cases, as regards axillary node status, were pathologically assessed as node negative. These patients did not receive any adjuvant treatment after mastectomy. At 36 months after mastectomy, the follow-up indicated that PgR- patients have a worse prognosis than PgR+ ones. This is evident when PgR alone is considered as a prognostic factor as well as when it is used to identify, within ER+ cases, those with a higher probability of relapse. In conclusion, it can be stated that although PgR status is an independent prognostic factor, it is useful to evaluate ER and PgR simultaneously for better patient management.

Hormonal and Receptor Status in Postmenopausal Women with Endometrial Carcinoma before and after Treatment with Tamoxifen

Twenty-four patients with endometrial carcinoma received tamoxifen (Nolvadex) for 7 days. Before and after administration, circulating hormones (estradiol, testosterone, progesterone, gonadotropins FSH and LH) were evaluated. Estrogen (ER) and progesterone receptors (PgR) in neoplastic tissue were also assayed. Our results show a net increase in PgR content and a signicant decrease in gonadotropin levels after the treatment. The authors suggest that clinical trials be conducted using tamoxifen and progestins for adjuvant therapy after surgery of endometrial carcinoma and for the therapeutic approach of advanced carcinoma.

Hormone Treatment and Sex Steroid Receptors in Metastatic Renal Cell Carcinoma: Report of a Multicentric Prospective Study

Twenty-eight patients with metastatic renal cell carcinoma entered a multicentric prospective study to evaluate the response to high-dose medroxyprogesterone acetate (MPA) and testosterone in MPA failures in relation to sex steroid receptors. No objective remission was seen in the 24 evaluable patients, and only disease stabilizations of short duration were achieved in one-third of treated patients. Stabilizations achieved with second line testosterone were all seen in patients unresponsive to MPA. Receptor studies demonstrated that estrogen, progesterone, or androgen receptors were found in low concentrations and in only 6 of 23 tumors (26%) and 13 normal tissue samples (56%). Surprisingly, no disease stabilization was achieved in patients positive for receptors. It can be concluded that the occasional objective responses to hormone therapy reported in the literature may have been due to some cytotoxic effect of hormone therapy rather than to a true hormonal mechanism.

Results of the Italian Interlaboratory Quality Control Program for Estradiol Receptor Assay

This article presents results of the first Italian quality control program for determining the estradiol receptor on lypophilized guinea pig and calf uteri. Despite considerable variability in quantitative terms, the results concur in ability to define samples as positive or negative for receptor content. One of the parameters that most strongly influences accuracy of determination of receptor concentration is protein assay. The evaluation of several lyophilized preparations at scalar concentrations permitted identification, by linear regression, for each laboratory of the systematic and non-systematic variables. More comparable results will be forthcoming when a standardized methodology program has been fully adopted.

Estrogen Receptors and MPA Treatment in Metastatic Renal Carcinoma. A Preliminary Report

Ten previously untreated patients with metastatic renal carcinoma underwent transperitoneal radical nephrectomy followed by high dosage MPA treatment. Estrogen receptors were determined in the specimen of all cases by the dextran-coated charcoal method: both the neoplastic tissue and the healthy parenchyma were tested. The disease progressed in 8 cases, and 2 patients are alive without any evidence of progressive disease 12 and 27 months after the operation. Very low receptor levels were detected in these 2 cases and one of them could be defined as borderline with our threshold criterion. However, receptors were undetectable in the neoplastic tissue from 4 of 8 patients who progressed. These questionable results justified the start of a prospective multicentric trial to study in a large number of cases both hormone receptors and clinical response to hormone therapy in human renal cancer.

Evaluation of Doxorubicin Cardiotoxicity in Patients Treated Intermittently with Beta-Methyldigoxin

Twenty-one patients with various advanced neoplasms were treated with 60 to 75 mg/m2 of doxorubicin every 3 to 4 weeks and monitored by ECG and systolic time intervals (PEP/LVET) with the aim to establish whether a pretreatment with beta-methyldigoxin, administered intermittently, could prevent doxorubicin-induced cardiotoxicity. It was found that until patients received digitalis pretreatment the PEP/LVET ratio did not change significantly from mean basal values even after the highest cumulative dosages of doxorubicin. However, after interruption of the therapy with both drugs, PEP/LVET increased reaching a value not significantly different from that observed in a comparable group of patients treated only with doxorubicin. Moreover, of 9 patients who reached the cumulative limiting dose, 2 developed congestive heart failure. These results question the possibility that digitalis administered according to an intermittent treatment scheme may prevent doxorubicin cardiomyopathy.

Relationship between Steroid Receptors (As Continuous Variables) and Response to Adjuvant Treatments in Postmenopausal Women with Node-Positive Breast Cancer

In current clinical practice for breast cancer patients, estrogen (ER) and progesterone receptor (PgR) concentrations, quantified by the dextran-coated charcoal assay, are categorized by an arbitrary cutoff into a negative or positive status. However, although the results obtained with this approach are easy to interpret, such a representation could oversimplify the relationship between ER and PgR content and patient outcome and imply an assumption of monotonicity, which is generally expected but rarely proven. We evaluated the relationship between ER and PgR content (considered on a continuous scale) and clinical outcome, using a flexible statistical model, in a group of postmenopausal patients with N-positive operable tumors who were submitted to surgery and different adjuvant treatments (tamoxifen or CMF). Univariate analysis indicated that in the tamoxifen-treated group, ER level, number of metastatic nodes (pN) and age, but not PgR, were significant indicators of clinical outcome (p=0.032, p=0.021 and p=0.029, respectively). Multivariate analysis indicated that in this group of patients there was no interaction between variables, and in the final model for disease-free survival (DFS) only ER and pN were retained with an overall predictive ability of the regression model of 0.723, as evaluated by Harrell's c. However, pN markedly contributed to the predictive ability of the model with respect to ER, since a marked decrease in Harrell's c statistic (c=0.582) was observed when pN was removed from the model. In the CMF-treated group, only pN affected clinical outcome. When the estimated DFS curves obtained from the final Cox regression models were plotted according to four values of ER (in the tamoxifen-treated group) or three values of pN (in the CMF-treated group) we observed that in the tamoxifen-treated group patients with an ER concentration equal to 0 fmol/mg cytosol protein had the worst prognosis, whereas a marked improvement of the expected DFS was observed for patients with a low but detectable ER level (generally classified as ER-negative because falling below the conventional cutoff value of 10 fmol/mg cytosol protein). Our results seem to suggest that the use of steroid receptor concentrations on a continuous scale, instead of dichotomous “status”, is to be preferred in the choice of adequate therapeutic strategies.

Effect of sodium butyrate on human breast cancer cell lines

We have investigated the effects exerted by sodium butyrate (NaBu) on the growth and cell cycle perturbations of four human breast cancer cell lines (MCF7, T47D, MDA-MB231 and BT20) with different steroid receptor profiles. Moreover, since one of the supposed mechanisms of action for NaBu activity involves the induction of apoptosis, we have studied the effects of NaBu on DNA fragmentation by agarose gel electrophoresis and flow cytometry. In all investigated cell lines, NaBu exerted a time- and dose-dependent inhibition of growth and caused a maximum inhibitory effect (85% to 90%) at the concentration of 2.5 mM. The inhibition was already evident after 3 days of treatment. The antiproliferative effect of NaBu was associated with a persistent block of cells in the G2M phase. The block was associated with apoptosis only in oestrogen-receptor positive cell lines. The inhibiting effect of NaBu in hormone-dependent and independent cell lines and its ability to induce apoptosis through a cell cycle perturbation in hormone-dependent cell lines may have important implications in the treatment of human tumours including breast cancer.

The antiproliferative effects of Uncaria tomentosa extracts and fractions on the growth of breast cancer cell line

Uncaria tomentosa, also known as "Uña de gato", is a Rubiaceae species widely used in South-American folk medicine for the treatment of cancer, arthritis, gastritis and epidemic diseases. Extracts of the plant have been shown to possess cytostatic and anti-inflammatory activity as well as mutagenic and antimutagenic properties. However, to date no studies have been carried out to verify the direct antitumor activity of the extracts. The present study investigates the effects of some extracts and their chromatographic fractions from the bark of U. tomentosa on the growth of a human breast cancer cell line (MCF7). Our data indicated that, in addition to the antimutagenic activity, U. tomentosa extracts and fractions exert a direct antiproliferative activity on MCF7. The bioassay-directed fractionation from barks and leaves resulted in the isolation of two active fractions, which displayed an IC50 of 10 mg/ml and 20 mg/ml, respectively and an antiproliferative effect, with about 90% of inhibition at a concentration of 100 mg/ml.

Genistein blocks breast cancer cells in the G(2)M phase of the cell cycle

Genistein, a natural isoflavone phytoestrogen present in soybeans, caused a dose-dependent growth inhibition of the two hormone-sensitive cell lines T47D and ZR75.1 and of the two hormone-independent cell lines MDAMB-231 and BT20. Flow cytometric analysis of cells treated for 4 days with 15 and 30 microM genistein showed a dose-dependent accumulation in the G(2)M phase of the cell cycle. At the highest tested concentration, there was a sevenfold increase in the percentage of cells in G(2)M (63%) with respect to the control (9%) in the case of T47D cells and a 2.4-fold increase in the case of BT20. An intermediate fourfold accumulation was observed in the case of MDAMB-231 and ZR75.1. The G(2)M arrest was coupled with a parallel depletion of the G(0)/G(1) phase. To understand the mechanism of action underlying the block in G(2)M induced by genistein, we investigated the expression and the activity of cyclins and of cyclin-dependent kinases specifically involved in the G(2)-->M transition. As expected, p34(cdc-2) expression, monitored by Western blotting, was unaffected by genistein treatment in all cell lines. With exception of the T47D cell line, we revealed an increase in the tyrosine phosphorylated form of p34, suggesting an inactivation of the p34(cdc-2) catalytic activity consequent to treatment of cells with genistein. In fact, immunoprecipitates from genistein-treated MDAMB-231 and BT20 cells displayed a fourfold decrease in kinase activity evaluated using the histone H1 as substrate. Conversely, no variation in kinase activity was observed between treated and untreated ZR75.1 cells despite the increase in p34 phosphorylation. In cells treated with 30 microM genistein, cyclin B(1) (p62) increased 2.8-,8-and 103-fold, respectively, in BT20, MDAMB-231, and ZR75.1 cells, suggesting an accumulation of the p62, which is instead rapidly degraded in cycling cells. No effects were observed on cyclin expression in T47D cells. We therefore conclude that genistein causes a G(2)M arrest in breast cancer cell lines, but that such growth arrest is not necessarily coupled with deregulation of the p34(cdc-2)/cyclin B(1) complex only in all of the studied cell lines.

P53 accumulation in primary breast cancer: a comparison between immunohistochemistry and a novel luminometric immunoassay

The accumulation of p53 protein was evaluated by a novel luminometric immunoassay (LIA) in cytosol samples from a series of 245 primary breast cancers. The cytosolic p53 content was not related to nodal status or hormone receptor status, but it was significantly and directly associated with tumor size and cell proliferation. A matched comparison between immunohistochemistry (IHC) and LIA results of individual tumors showed a significant association, albeit with a correlation coefficient of only 0.41. The agreement of results from the two assays was higher in node-positive, estrogen-receptor-negative and rapidly proliferating tumors than in the complementary subgroups. Overall, there was a significant trend in favor of an increase in p53 levels as determined by LIA with the increase in p53-positive cells shown by IHC. However, taking IHC detection as a reference, the sensitivity of the LIA was better for negative (86%) than for positive (61%) values. Based on these findings, a comparative assessment of the clinical relevance of LIA versus IHC results has to be recommended.

Time-dependent relevance of steroid receptors in breast cancer

PURPOSE

To analyze the time-dependent prognostic role of the investigated variables, considered, when appropriate, on a continuous scale, for the purpose of evaluating and describing the interrelationships between clinically relevant patient and tumor characteristics (age, size and histology, and estrogen receptor [ER] and progesterone receptor content) and the risk of new disease manifestation.

PATIENTS AND METHODS

We applied a flexible statistical model to a case series of 1,793 patients with axillary lymph node-negative breast cancer with a minimal potential follow-up of 10 years. To avoid a potential confounding effect of adjuvant treatment, only patients given local-regional therapy until relapse were considered.

RESULTS

ER content and tumor size (adjusted for all the other covariates) showed a time-dependent relationship with the risk of new disease manifestations. In particular, ER content failed to show a prognostic effect within the first years of follow-up; thereafter, a positive association with risk of relapse was observed. For tumor size, within the first years of follow-up, the risk of relapse was directly related to size for only tumors up to 2.5 cm in diameter; thereafter, the impact on prognosis progressively decreased.

CONCLUSION

The availability of a long follow-up on a large breast cancer series, as well as the use of innovative statistical approaches, allowed us to explore the functional relation between steroid receptors and clinical outcome and to generate a hypothesis on the involvement of ER in favoring long-term metastasis development.

The two phyto-oestrogens genistein and quercetin exert different effects on oestrogen receptor function

We compared the oestrogenic and anti-oestrogenic properties of the two well-known phyto-oestrogens, genistein and quercetin, on the oestrogen-sensitive breast cancer cell line MCF-7. Genistein exerted a biphasic effect on growth of MCF-7 cells, stimulating at low and inhibiting at high concentrations, whereas quercetin was only growth inhibitory. At doses which did not inhibit cell growth, respectively 5 and 1 microM, genistein and quercetin counteracted oestrogen- and transforming growth factor-alpha-promoted cell growth stimulation. Furthermore, genistein promoted transcription of the oestrogen-regulated genes pS2 and cathepsin-D, whereas quercetin interfered with the oestrogen-induced expression of the proteins. In in vitro binding experiments, genistein competed with oestradiol for binding to the oestrogen receptor (ER), but quercetin did not. Quercetin and genistein down-regulated cytoplasmic ER levels and promoted a tighter nuclear association of the ER, but only genistein was able to up-regulate progesterone receptor protein levels. In gel mobility assays, ER preincubation with oestradiol or with the two phyto-oestrogens led to the appearance of the same retarded band, excluding differences between the various complexes in binding to the consensus sequence. The data allowed us to conclude that quercetin acts like a pure anti-oestrogen, whereas genistein displays mixed agonist/antagonist properties, and to formulate a hypothesis on the possible mechanism of action of such phyto-oestrogens.

Simultaneous but not sequential treatment with sodium butyrate improves the antiproliferative effect of alpha- or beta-interferon on a breast cancer cell line

Clinical evidence indicates that alpha- and beta-interferon (alpha-IFN, beta-IFN) are only partially effective in human breast cancer. To improve their effectiveness, it has been proposed that differentiation inducers, such as sodium butyrate (NaB), be used to increase the IFN sensitivity of tumors. Therefore, we assessed concomitant or sequential combinations of low/intermediate concentrations of alpha-IFN or beta-IFN (10, 50 and 100 IU/ml) with a low concentration (0.1 mM) of NaB on a human breast cancer cell line (MDA-MB231), which exhibited a moderate sensitivity to IFN. Moreover, to verify the capability of NaB to potentiate IFN effectiveness by increasing IFN receptor (IFN-R) concentration, we investigated the effect of NaB on the synthesis of IFN-R. The concomitant presence of NaB and alpha-IFN or beta-IFN significantly improved the antiproliferative effect of the corresponding IFN alone. Conversely, the sequential treatment NaB-IFN did not enhance the inhibitory activity of the cytokine, although NaB was able to induce the expression of IFN-R. More likely, NaB induced the expression of some component of the IFN system, such as Stat1, Stat2 or p48, whose higher availability in the cytoplasmic compartment promotes formation of the multimeric transcription factor ISGF3, which induces the transcription of IFN-stimulated genes.

Effect of steroid receptors, pS2 and cathepsin D on the outcome of elderly breast cancer patients: an exploratory investigation

In 83 elderly breast cancer patients, oestrogen and progesterone receptors (ER, PgR), pS2 and cathepsin D (CathD) were evaluated for their possible prognostic role on disease-free survival (DFS). The biomarkers were determined on the same cytosol by using immunoradiometric assays, and the variables were considered on a continuous scale. Univariate analysis indicated a linear relationship between logarithmic hazard ratio (log(HR)) and the log(ER) and log(PgR) concentration, but a non-linear relationship between log(HR) and CathD. As regards pS2, there was no evidence of a relationship with log(HR). In multivariate analysis, log(ER) content did not have a significant prognostic role, whereas log(PgR) retained a significant prognostic role. As regards the predictive ability, log(PgR) was the best discriminator of outcome followed by CathD, whereas the contribution of log(ER) was negligible. In multivariate analysis, 2 models were considered: one with log(ER), pS2, CathD and the interaction between pS2 and CathD, and another with log(PgR), pS2, CathD and the interaction between pS2 and CathD. In the first model, log(ER) content did not have a significant prognostic role, whereas in the second model log(PgR) retained a significant prognostic role. Our findings indicate that the quantitative determination of pS2 and CathD, in addition to steroid receptors, on the same cytosolic fraction could be a complementary tool to describe all breast cancer patients rather than just the elderly and that the use of a continuous scale, instead of a simple dichotomous "status", may improve the biological information supplied by the variables.

Genistein in the control of breast cancer cell growth: insights into the mechanism of action in vitro

Genistein significantly inhibited cell growth (IC50 around 10 microM) of MCF-7, MDAMB-231 and HBL-100 cell lines, but not of skin-derived fibroblasts and counteracted the growth-stimulatory effects exerted by estradiol and growth factors. It abolished the paracrine stimulation observed in MCF-7 cells in co-culture with MDAMB-231 or fibroblasts. Genistein-treated cells accumulated in the S and G2/M phases of the cell cycle and underwent apoptosis. Genistein decreased tyrosine phosphorylation induced upon treatment with transforming growth factor-alpha. Finally, genistein bound the estrogen receptor (ER) (relative affinity constant Kd = 4 nM), induced pS2 and cathepsin-D transcription and increased nuclear ER levels.

Estrogen-receptor status of patients who underwent mastectomy for breast cancer with a disease-free interval of not less than 8 years

The authors present a series of 1,226 patients who underwent total or partial mastectomy for breast cancer, who for a period of no less than 8 years from surgery did not have a relapse or relapsed only after 8 years. The patients were evaluated for estrogen-receptor (ER) content of the primary tumor. In the group of 237 patients who relapsed, only 8.8% (21 of 237) were ER negative; in the group of 989 patients without a relapse, 24.1% (239 of 989) were ER negative. The difference was significant (p < 0.001). Therefore, the absence of hormone receptors (ER negative) indicates a favorable prognosis after a period of 8 years. For comparison, ER content in the group of patients who relapsed before 8 years was evaluated; the results showed a different prognosis from the ER-negative patients in this group. Because the behavior of ER-negative tumors in the cancer-affected breast is similar to that of non-hormone-dependent carcinomas arising in other parts of the body (which generally are considered cured after a long disease-free interval from surgery), we conclude that this repudiates the theory that confers to breast cancer the character of a systemic disease.

Is steroid receptor profile in contralateral breast cancer a marker of independence of the corresponding primary tumour?

We compared oestrogen receptor (ER) and progesterone receptor (PgR) profiles between primary and corresponding contralateral breast cancer (CBC) to investigate whether CBC should be considered relapse of a primary or as a feature of the multicentric origin of breast cancer. We adjusted for patient age, menopausal status, histology and adjuvant therapy. In spite of the general application of a cut-off value to dichotomise ER and PgR, we considered them as continuous variables. Moreover, we considered as synchronous cancers only simultaneously occurring lesions. For 399 patients, ER and PgR receptor levels in primary and CBC did not differ significantly, but were significantly correlated within the same patient. The correlation was higher for synchronous than for metachronous lesions when considering ER, but not PgR. The correlation between ER and PgR levels in the same tumour (primary or CBC) appeared stronger than the correlation of either receptor type (ER or PgR) between primary and CBC. Age, histology and adjuvant treatment affected ER concentration, whereas age, menopausal status and histology affected PgR concentration. The analysis indicated that primary and CBC tend to be characterised by a similar steroid receptor profile. The finding may support the hypothesis of CBC as a second primary arising in a common predisposing milieu, rather than a primary-dependent contralateral lesion. In this light, the clinical management of patients with a bilateral breast cancer should be similar to that of a unilateral breast cancer.

Expression of the kidney-associated differentiation glycoprotein gp160 and resistance to the antitumor effects of interferon alpha in renal cell carcinomas

BACKGROUND

Alpha interferon (IFN-alpha) is commonly used to treat patients with advanced renal cell carcinoma (RCC). We previously reported that resistance of RCCs to IFN-alpha in vitro correlated with the expression of a cell-surface glycoprotein of 160,00 kD molecular weight (gp160) which we subsequently identified as aminopeptidase A.

MATERIALS AND METHODS

To directly test the role of gp160/APA in IFN-resistance, we stably introduced the gp160/APA cDNA into IFN-sensitive SK-RC-49 cells resulting in the expression of an enzymatically active gp160/APA protein. In addition, to determine if gp160/APA expression could function as a marker of IFN-resistance in vivo, we assessed gp160/APA protein levels in autologous normal kidney and primary renal cancer specimens from 29 patients half of which were randomized to receive adjuvant IFN-alpha therapy following nephrectomy.

RESULTS

Four clones which possessed varying amounts of gp160/APA specific enzyme activity were assayed for sensitivity to the antiproliferative effects of IFN-alpha. All four clones exhibited sensitivity to IFN-alpha similar to that observed with parental SK-RC-49 cells. The analysis of tumor tissue detected no significant difference between the mean level of gp160/APA in tissue from control and IFN-alpha treated patients (1.33 A.U. versus 0.9981 A.U., p = 0.23); however, the mean gp160/APA level was significantly less in tumor tissue (mean = 1.15 A.U.) compared to normal tissue (mean = 2.15 A.U.; p < 0.00001). Within the IFN-alpha treated group, tumor gp160/APA levels did not correlate with the development of metastases or survival (p = 0.469).

CONCLUSIONS

These data indicate that gp160/APA does not directly convey IFN-resistance to RCC cells and suggest that expression of gp160/APA in primary RCCs does not predict the benefit of IFN-alpha therapy.

Effect of liposome-encapsulated alpha- or beta-interferon on breast cancer cell lines

Experimental evidence and clinical studies have indicated that interferons (IFN) inhibit proliferation in a wide panel of neoplasms, including breast cancer. However, the antitumor activity of IFN requires the continuous presence of high concentrations of the drug and is associated with side effects. To explore the potential of liposomes as an IFN delivery system, we compared the effect of free or liposome-encapsulated alpha-IFN and beta-IFN on the growth of two breast cancer cell lines (MCF7 and MDA-MB231). Cells were cultured in the presence of IFN at different concentrations (500, 1000, 2000 IU/ml) or in the presence of multilamellar liposomes (phosphatidylcholine-phosphatidylserine at a molar ratio of 7:3) containing saline buffer, alpha-IFN or beta-IFN. Additional control groups consisted of cells cultured with alpha-IFN or beta-IFN plus empty liposomes. Empty liposomes were not cytotoxic and did not interfere with IFN activity. In both cell lines liposomes encapsulating alpha-IFN (at the highest lipid:drug ratio) inhibited cell growth in a manner similar to that of free alpha-IFN, whereas liposomes encapsulating beta-IFN showed slightly, lower inhibition than free beta-IFN, this was more evident in MCF7 cells. The present results indicate that liposomes encapsulating alpha-IFN or beta-IFN were effective on the growth of both breast cancer cell lines, which are characterized by a different estrogen responsiveness, and that they might be a useful carrier system for the delivery of high doses of IFN.

int-2 oncogene amplification and prognosis in node-negative breast carcinoma

The role of int-2 oncogene amplification on the prognosis of breast cancer patients was investigated in 128 patients with node-negative primary breast cancers given first-line local-regional treatments until relapse and with a median follow-up of 65 months. Tumours had been previously characterised for oestrogen (ER) and progesterone receptor (PgR) status and proliferative activity (3H-thymidine labelling index). Amplification of the int-2 oncogene occurred in 18% of cases and was significantly related to the presence of hormone receptors and to menopausal status or age, but not to proliferative status. Patients with tumours exhibiting int-2 amplification had a lower probability of disease-free survival than patients with non-amplified tumours and frequently developed local-regional recurrence. Disease-free survival analysis, adjusted for the prognostic contribution provided by tumour size, steroid receptors and proliferative rate, indicated that the association between int-2 amplification and risk of relapse was maintained and remained constant even in the presence of the other co-variates. Interestingly, int-2 amplification was a further prognostic discriminant within subsets of patients with a putatively good (i.e., tumour size <20 mm, ER+ and PgR+) or poor prognosis (i.e., high labelling index). Our exploratory study suggests that within node-negative patients, int-2 amplification could be a valuable and independent prognosticator, useful to identify patients at high risk of local-regional recurrence.

Combined effect of tamoxifen or interferon-beta and 4-hydroxyphenylretinamide on the growth of breast cancer cell lines

To improve the effectiveness of 4-hydroxyphenylretinamide (4-HPR), an analogue of retinoic acid used in chemoprevention and treatment of breast cancer, we investigated the effect of concomitant administration of 4-HPR (0.1, 1 microM) and tamoxifen (TAM, 0.1, 1 microM), or 4-HPR and interferon-beta (IFN-beta, 10, 100, 500 IU/ml) on the growth of four cell lines (MCF7, T47D, MDA-MB231 and BT20) characterized by a different steroid receptor profile. A high concentration of 4-HPR caused a significant inhibitory effect not only on the estrogen receptor-positive cell lines (MCF7 and T47D), but also on one (BT20) of the two estrogen receptor-negative cell lines. IFN-beta displayed a dose-dependent inhibitory effect in all cell lines, but it was most evident in MCF7 cells. In all cell lines, the combination of 4-HPR (0.1 microM) and TAM (1 microM) or IFN-beta (500 IU/ml) generally caused additive or synergistic effects. In particular, the finding that in estrogen receptor-negative MDA-MB231 cells 4-HPR (which at 1 microM was singly ineffective) in combination with TAM at 1 microM or any concentration of IFN-beta produced a synergistic effect suggests that the compound could act through a pathway independent of specific receptors for retinoids. Our results indicate that intrinsic characteristics of cells can influence responsiveness to 4-HPR, TAM and IFN-beta, singly or in association, ever within cell lines with similar steroid receptor profiles. Thus, more attention should be payed to the biological characteristics of the single tumor in order to help choose the best combination of drugs to be applied.

Antiproliferative effect of fermented milk on the growth of a human breast cancer cell line

In vivo and in vitro studies have shown an antitumor activity of Lactobacilli in colon cancer, and some epidemiologic studies have indicated a reduced risk of breast cancer in women who consume fermented milk products. We studied the direct effect of milk fermented by five bacteria strains (Bifidobacterium infantis, Bifidobacterium bifidum, Bifidobacterium animalis, Lactobacillus acidophilus, and Lactobacillus paracasei) on the growth of the MCF7 breast cancer cell line. Our results showed a growth inhibition induced by all fermented milks, even though B. infantis and L. acidophilus were the most effective (85% inhibition after 9 days). The antiproliferative effect was not related to the presence of bacteria in fermented milk, and neither whole milk (crude or ultrahigh temperature sterlizied) nor its main fractions (lactalbumin or beta-lactoglobulin fraction) affected cell growth. Our findings suggest the presence of an ex novo soluble compound produced by lactic acid bacteria during milk fermentation or the microbial transformation of some milk components in a biologically active form. Although the mechanism of the antitumor activity is not clear, the present study suggests the potentiality offered by fermented milk as producers of compounds with antiproliferative activity useful in the prevention and therapy of solid tumors like breast cancer.

Modulation of cathepsin-D and pS2 protein levels in human breast cancer cell lines

Cathepsin-D and pS2 are two estrogen-regulated proteins in human breast cancer cell lines. They have been considered possible prognostic factors in breast cancer, but results have been contradictory. To better understand the regulation of these proteins, we investigated the role of estradiol (E2), serum, and growth factors in hormone-dependent (MCF-7, ZR75.1) and hormone-independent (MDAMB-231, BT20) breast cancer cell lines. E2 treatment in serum-free conditions increased intracellular and secreted levels of pS2 in ZR75.1 and in MCF-7, secreted levels only of cathepsin-D in MCF-7, and both levels of cathepsin-D in ZR75.1. Insulin-like growth factor I (IGF-I) and progesterone receptors were also stimulated by E2, whereas the estrogen receptor was down-regulated. Following treatment with epidermal growth factor (EGF), secreted pS2 levels doubled only in MCF-7 cells. IGF-I did not modify cathepsin-D or pS2 levels in either cell line, but caused an increase in its own receptor. Cathepsin-D and pS2 doubled in MCF-7 cells grown in medium supplemented with denaturated serum, but estrogen regulation of these proteins was still maintained. Cathepsin-D was expressed in MDAMB-231 and BT20, but its levels were modified by neither E2 nor growth factor treatment. Conversely, neither cell line expressed detectable levels of pS2 before or after treatment. In conclusion, our results show that in different types of breast cancer cells, some estrogen-regulated proteins (e.g. pS2) are also regulated by growth factors-such as EGF and other unknown serum factors. This may account for the contradictory results obtained regarding the prognostic relevance of cathepsin-D and pS2.

Effect of progestin treatment on estradiol-and growth factor-stimulated breast cancer cell lines

BACKGROUND

Reports about the effects of progestins on cell proliferation are contradictory. We investigated the effect of progesterone, medroxyprogesterone acetate, megestrol acetate, ORG 2058 and the antiprogestin RU 486 on two hormone-dependent cell lines, T47D and MCF-7 (characterized by a different content of PgR). The aim of the study was to understand the eventual ability of progestins to interfere with cell proliferation stimulated by estradiol and various growth factors (TGF-a, IGF-I, IGF-II).

MATERIAL AND METHODS

MCF-7 and T47D cells were maintained in DMEM/F12 medium supplemented with 2% FCS while experiments were carried out in the same culture medium using DCC-stripped FCS.

RESULTS

In the absence of estradiol, all tested progestins generally tended to stimulate cell growth in the T47D cell line, but in the MCF-7 cell line only the highest concentrations (10(-6) M and 10(-7) M) were found to be stimulatory. In contrast, in the presence of 10(-8) M estradiol, progestins tended to inhibit cell growth stimulation in MCF-7 and T47D cell lines. The antiprogestin RU 486 exerted a stimulatory effect similar to that promoted by estradiol itself in MCF-7 cells. Instead, in T47D cells, RU 486 did not modify cell growth in the absence of estradiol, but tended to counteract the estradiol-promoted cell proliferation. In MCF-7 cells, medroxyprogesterone acetate and megestrol acetate were also able to effectively counteract the cell growth induced by TGF-alpha. However, none of these progestins was able to abolish cell proliferation promoted by IGF-I or IGF-II.

CONCLUSION

We therefore concluded that failure to respond to progestin treatment may be due to the very heterogeneous nature of human breast tumors and to the inability of these molecules to interfere with the IGF-R pathway.

The effect of ICI 164384 and beta-interferon on the growth and steroid receptor profile of breast cancer cell lines

We investigated the effect of a concomitant treatment of ICI 164384 and B-interferon (beta-IFN) on the growth of estrogen-receptor-positive (ER+) and estrogen-receptor-negative (ER-) breast cancer cell lines and on their steroid receptor profiles. ICI 164384 reduced cell proliferation not only in ER+ but also in ER- cell lines and completely suppressed the stimulation induced by estradiol (E2) in hormone-sensitive cell lines, MCF7 and T47D. When associated with beta-IFN, ICI 164384 increased the inhibitory effect exerted by the low concentration of beta-IFN. Moreover, ICI 164384, singly or in association with beta-IFN, did not affect ER and PgR concentration in ER- cell lines, whereas in ER+ cell lines we observed an almost total disappearance of ER and PgR. In conclusion, our study seems to indicate that, although beta-IFN is able to control the proliferation of hormone-sensitive and hormone-independent subclones, it does not further improve the antiproliferative activity of ICI 164384. In contrast, the presence of ICI 164384, which does not induce the selection of resistant subclones under the same experimental conditions in which TAM does, may improve the efficacy of low concentration of beta-IFN and prevent the development of a secondary TAM-induced resistance.

Biologic and clinicopathologic factors as indicators of specific relapse types in node-negative breast cancer

PURPOSE AND METHODS

We evaluated, in 1,800 patients with node-negative tumors treated with locoregional therapy until relapse, the competitive risks for different types of metastasis by cell proliferation (3H-thymidine labeling index [3H-dT LI]), estrogen receptors (ERs), and progesterone receptors (PgRs), and by the integration of biologic and clinicopathologic information.

RESULTS

Hormone receptor status and proliferative activity of the primary tumor were not indicative of contralateral failures. Hormone receptors failed to predict the 8-year incidence of locoregional recurrence, but they were significant indicators of distant metastasis and overall survival. The latter finding was confirmed even in multivariate analysis. Conversely, cell proliferation predicted both locoregional and distant metastases and survival, regardless of patient age, tumor size, and ER and PgR status. Recursive partitioning and amalgamation analysis ascribed to cell proliferation an important prognostic role for locoregional recurrence together with patient age and tumor size.

CONCLUSION

Biologic markers, in particular cell proliferation, provide information for the different types of relapse and could complement the predictive role of pathologic staging.

Tamoxifen and beta-interferon: effect of simultaneous or sequential treatment on breast cancer cell lines

The presence of steroid receptors in breast cancer is usually considered as a good indicator for responsiveness to antiestrogen treatment. However, not all estrogen-receptor (ER) positive tumors respond to tamoxifen, probably owing to the natural heterogeneity of breast cancer, which after tamoxifen treatment can result in an overgrowth of selected ER-negative clones. Since in a previous study we found that beta-interferon exerts an antiproliferative activity on several breast cancer cell lines, regardless of their steroid receptor status, we addressed our attention to the possibility of improving tamoifen efficacy by the addition of beta-interferon. Thus, we investigated the effect of concomitant or sequential treatment with tamoxifen and beta-interferon on breast cancer cell lines (MCF7, T47D, MDA-MB231, BT20) characterized by a different steroid receptor status. The results showed that beta-interferon caused a cell growth inhibition additional to that produced by tamoxifen, regardless of the receptor status of the cell lines. These findings indicate the potential of the combined treatment with tamoxifen and beta-interferon due to the direct effect of beta-interferon on ER-negative cells and the potentiation of tamoxifen activity in ER-positive cells, perhaps through the induction of steroid receptor synthesis.

The effect of alpha-, beta- and gamma-interferon on the growth of breast cancer cell lines

We investigated the antiproliferative effect of different concentrations (10, 100, 1000 IU/ml) of alpha-, beta- and gamma-interferons (IFN) on breast cancer cell lines. Cell lines were treated with IFN, in the absence or in the presence of estradiol for 9 days, and the effect on growth was evaluated as variation in DNA content. Inhibitory effect varied as a function of the type of interferon and cell line. Alpha-IFN and gamma-IFN were effective only at 1000 IU/ml and not in all cell lines, whereas a maximum effect was observed for beta-IFN regardless of the steroid receptor status of cell lines. In fact, a significant growth inhibition was observed at the intermediate concentration of 100 IU/ml in all but MDA-MB231 cell lines. Moreover, in both estrogen-receptor positive cell lines, beta-IFN counteracted growth stimulation induced by estradiol and showed a strong antiestrogenic activity. In conclusion, our results show that beta-IFN is the most active among the IFNs tested and suggest its usefulness in the treatment of all breast cancers, irrespective of their steroid receptor status.

Activity of tamoxifen and new antiestrogens on estrogen receptor positive and negative breast cancer cells

The effect of some new antiestrogens (ICI 164384, ICI 182780, Ly 133314 and Ly 117018) on the growth of a panel of breast cancer cell lines (MDA-MB 231, BT20, MCF7 and T47D) was studied. Their antiestrogenic activity was investigated in the presence of a physiologic concentration of estradiol and compared with the effect displayed by tamoxifen in the same experimental conditions. Tamoxifen confirmed its antagonistic activity in the presence of estradiol, whereas when given alone it did not exhibit a clear antiproliferative effect. All other compounds showed variable activity: ICI 164384 and ICI 182780 exerted a variable inhibitory effect in all cell lines, but only in the absence of estradiol; Ly 133314 and Ly 117018 did not show a clear antagonistic activity and sometimes had a synergistic effect with estradiol in increasing cell growth. These results indicate an extreme variability in terms of antagonistic effect of these new compounds and suggest their inadequacy to replace tamoxifen as an antiestrogen during endocrine treatment. Interestingly, ICI 164384 exerted an antiproliferative action also an estrogen receptor-negative cell lines, probably through an alternative mechanism non estrogen receptor-mediated, supporting the hypothesis that it could be effective on estrogen receptor-positive as well as estrogen receptor-negative tumors.

The Bcl-2 protein: a prognostic indicator strongly related to p53 protein in lymph node-negative breast cancer patients

BACKGROUND

The bcl-2 gene (also known as BCL2) encodes for a mitochondrial protein thought to prevent apoptosis of normal cells. The protein has been detected by immunohistochemical procedures in hormonally regulated epithelia.

PURPOSE

We analyzed the predictive relevance of Bcl-2 expression on 6-year relapse-free and overall survival in lymph node-negative breast cancers in relation to pathologic (tumor size) and biologic ([3H]thymidine-labeling index, p53 protein expression, and estrogen receptor [ER] status) features.

METHODS

The expression of Bcl-2 and p53 was detected by immunohistochemistry on paraffin-embedded sections from 283 node-negative resectable breast cancers treated with local-regional therapy alone until relapse. The [3H]thymidine-labeling index was evaluated on histologic sections after incubation of fresh tumor tissue with [3H]thymidine, and ER content was determined by the dextran-coated charcoal absorption technique.

RESULTS

A significantly higher fraction of Bcl-2-positive cells was observed in small, ER-positive, slowly proliferating, and p53-negative tumors than in large, ER-negative, rapidly proliferating, and p53-positive tumors. A stronger association was observed between Bcl-2 and p53 expression than between these variables and [3H]thymidine-labeling index. In univariate analysis, Bcl-2 and p53 expression, [3H]thymidine-labeling index, tumor size, and ER status were indicators for relapse-free and, with the exception of tumor size, overall survival within 6 years of surgery. In multivariate analysis, Bcl-2 failed to maintain its prognostic role for relapse-free and overall survival in the presence of p53 expression, whereas the [3H]thymidine-labeling index was still statistically significant as a predictor for both events.

CONCLUSION

The predictive role of Bcl-2 expression on 6-year relapse-free and overall survival was mainly dependent on p53 expression.

p53 as an independent prognostic marker in lymph node-negative breast cancer patients

BACKGROUND

At present, most decisions concerning the use of adjuvant therapy in lymph node-negative breast cancer patients are made on the basis of traditional factors such as tumor size, nodal status, and histopathologic features. However, prognostic factors are being investigated that could identify high-risk groups and that could better address treatment efforts for those patients. Identification of more accurate prognostic markers, such as the expression of the mutant p53 protein encoded by the p53 (also known as TP53) tumor suppressor gene, that are reproducible, easily assessable, and independent in predicting clinical outcome would have a beneficial impact on cancer treatment decisions.

PURPOSE

Our purpose was to analyze the predictive relevance of mutant p53 protein expression on 6-year relapse-free and overall survival in node-negative breast cancer patients in relation to menopausal status, tumor size, cell kinetics, and estrogen receptor status.

METHODS

Expression of mutant p53 protein was detected by an immunohistochemical technique using a 1:50 dilution of PAb1801 monoclonal antibody on paraffin-embedded tumor specimens obtained from 256 axillary lymph node-negative breast cancer patients, with long-term follow-up (median, 72 months). The [3H]thymidine labeling index, a measure of cell kinetics, was evaluated on histologic sections after fresh tumor tissue was labeled with [3H]thymidine. Estrogen receptor status was determined by the dextran-coated charcoal absorption technique. Statistical comparisons were made for levels of p53 protein expression, [3H]thymidine labeling index, estrogen receptor status, tumor size, and menopausal status with respect to 6-year relapse-free survival and overall survival.

RESULTS

Overexpression of the p53 protein, defined as the presence of more than 5% positive cells, was detected in 113 (44%) of 256 tumors. Odds ratios (ORs) for multiple regression analysis of 6-year relapse-free survival were significantly higher for p53 (OR = 3.24; 95% confidence limits [CL] = 2.01-5.23) and [3H]thymidine labeling index (OR = 1.92; 95% CL = 1.19-3.12), both of which appeared to be the most relevant indicators of relapse, than for tumor size (OR = 1.49; 95% CL = 0.94-2.38) and estrogen receptor status (OR = 0.91; 95% CL = 0.55-1.51). Overexpression was found to be unrelated to menopausal status.

CONCLUSIONS

Immunohistochemically detected p53 overexpression is an independent marker for shortened 6-year relapse-free and overall survival in node-negative patients with resectable breast cancers. Based on these findings, p53 overexpression should be used with other established prognostic factors, such as [3H]thymidine labeling index and estrogen receptor status, to further refine the prognostic assessment of node-negative breast cancer.

Cell kinetics as a predictive factor in node-positive breast cancer treated with adjuvant hormone therapy

PURPOSE

The fraction of cells that incorporate 3H-thymidine (3H-dT labeling index [3H-dT LI]) proved to be a prognostic indicator in patients with node-negative and node-positive resectable breast cancers treated with locoregional treatment alone or with adjuvant combination chemotherapy. In this study, we assessed the prognostic role of 3H-dT LI alone and in association with other pathologic and biologic variables in a series of 249 women with node-positive breast cancers treated with adjuvant endocrine therapy.

PATIENTS AND METHODS

All patients were postmenopausal, had resectable estrogen receptor-positive (ER+) tumors, and had received tamoxifen for at least 1 year after radical or conservative surgery plus radiotherapy. The median follow-up duration was 48 months.

RESULTS

The 4-year relapse-free survival (RFS) rates were significantly lower for patients with large tumors (> 2 cm), with more than three positive lymph nodes, with low (< 150 fmol/mg proteins) ER content, without progesterone receptors (PgRs), or with rapidly proliferating tumors. 3H-dT LI provided prognostic information independent of axillary node involvement, ER content, PgR status, and tumor size, with an estimated odds ratio (OR) higher than that of tumor size, lymph node involvement, or ER concentration. In addition, 3H-dT LI and PgR in association were able to identify patients with different risks of relapse within subsets of tumors with less or more than three positive nodes.

CONCLUSION

3H-dT LI provides prognostic information complementary to PgR, tumor size, lymph node involvement, and ER content in the prediction of RFS of postmenopausal patients with node-positive, ER + resectable tumors treated with adjuvant hormone therapy.

Prognostic significance of proliferative activity and ploidy in node-negative breast cancers

BACKGROUND

Cell kinetics and DNA ploidy have provided relevant information on the natural history of breast cancer. We assessed the prognostic role of proliferative activity and ploidy, alone and in association with tumor size, estrogen (ER) and progesterone (PgR) receptors.

PATIENTS AND METHODS

In a series of 340 women with resectable node-negative breast cancers given local-regional therapy alone until relapse, proliferative activity was determined as the 3H-thymidine labeling index (3H-dT LI) and flow-cytometric S-phase cell fraction (FCM-S), as quantified by using different modeling systems. DNA ploidy, ER and PgR content were determined on frozen samples by FCM and by the dextran-coated charcoal absorption technique, respectively.

RESULTS

FCM-S estimates obtained by the different models were weakly associated with one another and to the corresponding 3H-dT LIs. Four-year relapse-free survival was significantly predicted by 3H-dT LI, ploidy and tumor size but not by FCM-S. Multiple regression analysis showed that 3H-dT LI, ploidy and tumor size retained their prognostic significance and that 3H-dT LI was the most significant indicator of relapse (p = 0.009).

CONCLUSIONS

The finding that 3H-dT LI and ploidy are weakly related and provide independent prognostic information could allow a more accurate identification of patients at different risk of relapse.

Paracrine interaction in co-culture of hormone-dependent and independent breast cancer cells

A permeable solid support (Transwell Coll.) was used to develop serum-free co-cultures allowing paracrine interactions between hormone-dependent (MCF-7, ZR75.1) and hormone-independent (MDAMB-231, BT20) breast cancer cell lines. Both hormone-independent cell lines were able to stimulate the growth of the hormone-dependent lines, whereas the opposite was observed only in the case of BT20 co-culture with ZR75.1 cells. The cell growth stimulation observed in co-cultures could be abolished by the addition to the culture medium of an excess of transforming growth factor alpha (TGF alpha) or insulin-like growth factor I (IGF-I). Similarly, treatment with a neutralizing anti TGF alpha antibody impaired the growth stimulation exerted by hormone-independent cells on hormone-dependent cells. These results confirm the important role of paracrine interactions in control of the growth of human heterogeneous breast tumors and suggest that the main growth factors involved in such interactions are TGF alpha and probably some growth factors from the insulin-like growth factor family rather than IGF-I itself.

Quantitative immunohistochemical determination of cathepsin-D and its relation with other variables

The expression of cathepsin D was evaluated by immunohistochemistry on histologic sections from formalin-fixed samples in a series of 436 primary breast cancers. The fraction of cathepsin D-positive tumor cells was not related to tumor size or hormone receptor status, and only weakly related to proliferative activity, evaluated as the 3H-thymidine labeling index. Conversely, a higher fraction of positive cells was observed in node-positive than in node-negative tumors (p = 0.05). A matched comparison between immunohistochemical and immunoradiometric results on individual tumors was carried out on 100 cases and showed a significant association but with a correlation coefficient of 0.46. The agreement of results from the two assays was higher in ER- than in ER+ tumors, which sometimes showed an immunostaining limited to macrophages and normal epithelial cells. In situ evaluation has the main advantage of being specifically applicable to detection in tumor cells and allows the simultaneous determination of different biologic aspects for a more complete understanding of breast cancer biology.

Study of the biological and prognostic significance of the antigen CaMBr8 on breast carcinoma

We previously reported that the expression on the primary tumour of the antigen CaMBr8 was related to a short survival, attributable either to higher tumour aggressiveness or a poor response to oophorectomy. To further verify the CaMBr8 prognostic value, we analysed retrospectively 862 breast cancer patients with a 19 year follow-up. In this series, CaMBr8 expression was found to be associated to some negative prognostic factors (premenopausal status, lymphnode invasion, a high number of mitosis and HER-2/neu oncoprotein expression), but had no influence on the patients' survival. Direct association with a poor prognosis was only evident in patients with lobular or mixed breast carcinoma, which however represent only a small fraction of the total breast cancers. Another possibility was that CaMBr8 could identify a subgroup of patients which did not respond to hormone therapy. To verify this hypothesis we evaluated on a second series of 116 patients the relationship between CaMBr8 expression and hormone-receptor levels. A negative association emerged which was also observed in vitro in the human breast cancer line MCF-7 treated with Sodium Butyrate, a differentiation inducer, which reduced hormone-receptor levels and increased CaMBr8 expression. In conclusion, the longer survival of CaMBr8 negative tumour patients observed in the initial study, was probably related to a better response to oophorectomy, due to the hormone-receptor level of their tumours.

Prognostic relevance of pS2 status in association with steroid receptor status and proliferative activity in node-negative breast cancer

Expression of the oestrogen-regulated pS2 protein was investigated on paraffin-embedded sections of primary breast tumours from 200 node-negative patients. Immunoreactivity was observed in 56% of the cases. pS2 expression was inversely correlated with tumour size and proliferative activity, whereas a direct correlation was observed with steroid receptor. 5-year relapse free survival was influenced by tumour size (P = 0.02), oestrogen receptor status (P less than 0.05), and proliferative activity (P less than 0.01). No difference in relapse-free survival was observed between patients subdivided according to pS2 expression alone. However, among patients with oestrogen-receptor-negative tumors, pS2 expression predicted a shorter relapse-free survival.

Biological characterisation of primary and metachronous lesions in breast cancer patients

Proliferative activity, evaluated as [3H]thymidine labelling index ([3H]dT LI), and hormone receptors were determined on 97 primary breast cancers and on metachronous lesions from the same patient. Overall, the [3H]dT LI of metachronous lesions was significantly higher than that of the primary tumour (P = 0.003). Hormone receptor profiles of the two lesions were similar in about 75% of the cases; disagreements were mainly due to a disappearance of hormone receptors in metachronous lesions. In contralateral tumours, [3H]dT LI and hormone receptors were unrelated to those of the relative primary lesion. In this series of relapsing patients, [3H]dT LI was unrelated to hormone receptor status in the primary tumour, but it was higher in the metachronous lesions from patients with hormone receptor-negative primary tumours. For patients given no systemic therapy between surgery and relapse, the time to develop local-regional recurrences or contralateral tumours was inversely related to the [3H]dT LI of the metachronous lesions.

Adjuvant hormone treatment and chemotherapy in postmenopausal women with operable breast cancer: a retrospective analysis

Two hundred consecutive postmenopausal women with operable breast cancer and metastatic axillary nodes were treated during the period January - December 1981 with adjuvant chemotherapy (CMF) or hormonal treatment (tamoxifen). The distribution of receptor status (estrogen or progesterone), number of axillary metastatic nodes (less than = 3 or greater than 3), surgical treatment and size of the primary tumor were homogeneous in both groups. Receptor status and number of axillary lymph nodes were correlated with adjuvant treatment efficacy. Ten-year disease-free survival (DFS) was higher in the TAM-treated (72%) than in the CMF-treated group (52%) (p less than 0.01). In patients with less than = 3 axillary metastatic nodes, those treated with TAM had a higher DFS rate than those treated with CMF (75% vs 59%, p less than 0.01). There was no difference in DFS between CMF-and TAM-treated groups within the greater than 3 metastatic lymph node patients. In ER + primary tumors, DFS was higher in the subset treated with TAM (62%) than with CMF (51%) (p less than 0.05), whereas no difference in DFS was observed in ER- patients between the two treatment groups. Considering the TAM group, DFS was better (p less than 0.01) for ER+ cases than for ER- cases only at 5 years of observation. In the CMF group, DFS was not influenced by ER status. PgR content did not affect DFS in either adjuvant treatment group.

Effects of toremifene and its main metabolites on growth of breast cancer cell lines

The effects of toremifene, an antiestrogen, and its two main metabolites (4-hydroxy- and N-desmethyltoremifene) on cell proliferation have been tested in a series of breast cancer cell lines, with positive (MCF7, ZR 75.1, T47D, 734B) or negative steroid receptor status (MDA-MB 231, BT20). Drug effects were evaluated at concentrations similar to those obtained in breast cancer patients on toremifene treatment, and in the presence or absence of estradiol. Results showed that, for both positive and negative cell lines, high concentrations of the antiestrogens (10(-6)M) were inhibitory, while lower doses (10(-7)M, 10(-8)M) were stimulatory. These data confirm the biphasic behaviour of toremifene and its derivatives. In terms of a clinical application of toremifene, these results seem to suggest that while high doses of toremifene and its derivatives might be therapeutic, lower concentrations might stimulate cell growth and enhance tumor progression.

Interaction between hormone-dependent and hormone-independent human breast cancer cells

We developed two different models based on in vitro co-culture of hormone-dependent and hormone-independent cell lines to simulate the cell population heterogeneity of human breast cancer tumours. Oestrogen-dependent (MCF-7, ZR 75.1) and oestrogen-independent cell lines (MDAMB-231 BT-20) were grown under serum-free conditions. Co-culture of hormone-dependent and hormone-independent cell lines resulted in an increased cell yield compared to single cell cultures carried out at the same seeding ratios. Such an increase was not affected by addition of oestradiol and single growth factors (EGF, bFGF and IGF-I). These results allow us to conclude that in a heterogeneous cell population like human breast tumours, interaction between hormone-dependent and hormone-independent cell lines may result in a complex regulation of cell growth.