Correlations between estrogen receptor, progesterone receptor, and patient characteristics in human breast cancer

The relationships between estrogen receptor, progesterone receptor, and a variety of patient characteristics are described for 2,977 women with primary breast cancer. Older women were more likely to be estrogen-receptor positive than younger women. When patient age and menopausal status were analyzed together, age was found to be the primary determinant of increased estrogen-receptor concentrations. There appeared to be no relationship with progesterone receptor for either age or menopausal status when these variables were analyzed separately. But premenopausal women had higher progesterone receptor concentrations than postmenopausal women when patients of the same age were compared, perhaps reflecting greater estrogen-mediated synthesis of progesterone receptor. Tumor size was negatively related to steroid receptor concentrations, but no relationships were observed between steroid receptors and either the number of positive axillary lymph nodes or the location of the primary tumor.

Perturbation by insulin of human breast cancer cell cycle kinetics

The growth of cultured human breast cancer cells is sensitive to physiological concentrations of insulin suggesting that it may regulate breast cancer growth in vivo. The mechanisms for the growth effects of insulin are poorly defined. In the present study, we examine the effects of insulin on the cell cycle kinetics of asynchronous MCF-7 human breast cancer cells growing in serum-free medium. When the [3H]thymidine labeling index is used to estimate the S-phase fraction, insulin added to asynchronously growing cells results in a time-dependent increase in the proportion of cells engaged in DNA synthesis. Computer analysis of DNA histograms obtained by flow cytometry of mithramycin-stained cells also shows a time-dependent progression of cells into and through the S-phase compartment. Sixteen hr after adding insulin to asynchronous cells, 66% of cells are in S-phase compared to 37% in controls. The effect of insulin on the cell cycle progression of MCF-7 cells is also dose dependent. Stimulation is observed with physiological insulin concentrations of 0.1 to 1.0 nM; maximal effects are observed with 1.0 to 10 nM insulin. Various insulin analogues enhance the progression of cells into S phase in proportion to their ability to bind to the insulin receptor in MCF-7 cells (porcine greater than or equal to chicken greater than guinea pig greater than deoctapeptide insulin), while unrelated peptide hormones have no effect on the cell cycle kinetics. Cell cycle analysis after the addition of colchicine to prevent mitosis and the reentry of cells into G1 demonstrates a shortened G1 in response to insulin. Continuous [3H]thymidine-labeling studies after the addition of colchicine suggest that the growth fraction is about 88% with or without insulin. In summary, insulin causes a marked perturbation of the cell cycle kinetics of MCF-7 human breast cancer cells by facilitating the transit of cells through G1. The data also suggest that this effect is mediated via the insulin receptor.

Human breast cancer cell cycle synchronization by estrogens and antiestrogens in culture

The mechanisms by which estrogens and antiestrogens modulate breast cancer growth have not been totally defined. We have examined the cell cycle kinetic effects of estrogens and antiestrogens in cultured human breast cancer cell lines. In a previous study, we showed that tamoxifen induces a transition delay in early to mid-G1 phase of the cell cycle. In the present study, we show that this cell kinetic alteration by tamoxifen is dose dependent and that other antiestrogens have identical effects. As little as 0.01 to 0.1 microM tamoxifen reduces the S and G2 + M fractions and increases the G1 fraction of MCF-7 cells growing in medium with 5% charcoal-stripped bovine serum. More than 90% of cells are in G1 72 to 96 hr after the addition of 1 microM tamoxifen, a concentration achieved in patients treated with the drug. Nafoxidine and trioxifene have identical activity. Partial reversal of tamoxifen growth inhibition is observed with a simple change to tamoxifen-free medium. Complete reversal of the tamoxifen effect is observed with the addition of 17 beta-estradiol. By 24 hr after the addition of estrogen, 60 to 70% of tamoxifen-inhibited cells have progressed through G1 and into S phase, indicating that tamoxifen-treated cells remain viable. This estrogen "rescue" effect is observed even in the absence of a change to tamoxifen-free medium. A 100-fold-lower concentration of estradiol can totally reverse the inhibitory effects of 1.0 microM tamoxifen. Stimulation of the progression of G1 cells to enter S phase is also observed when estradiol is added to cells maintained for four days in medium with stripped serum, even in the absence of tamoxifen. Similar effects are observed in the estrogen receptor-positive ZR75-1 breast cancer cells. No effects of antiestrogens or estrogens are observed in the receptor-negative MDA-231 cells, suggesting that these effects are mediated through the estrogen receptor. In summary, antiestrogens and estrogens have prominent effects on the cell cycle kinetics of endocrine-dependent human breast cancer cells. Antiestrogens cause an accumulation of cells in G1 phase. Estrogen reverses this block with a synchronous cohort of cells progressing through the cell cycle. These data have important implications for the design of rational clinical trials of combined chemoendocrine therapy.

Bisantrene, an active drug in patients with advanced breast cancer

We have previously reported that bisantrene has significant activity against a variety of tumors in the human tumor soft agar cloning assay. An update of that experience reveals that 26% of evaluable human breast cancer specimens were sensitive to bisantrene, which had activity equivalent or superior to that of doxorubicin. Because of the preclinical activity of bisantrene and its activity in the cloning assay, bisantrene was studied in a phase II clinical trial of 30 patients with advanced breast cancer refractory to standard agents. Six patients (20%) had objective complete or partial regressions, including one patient with complete regression of lymphangitic lung metastases lasting greater than 18 months, confirming the antitumor activity of this compound. Two of the six responding patients had failed doxorubicin treatment, implying a lack of complete cross-resistance. Bisantrene toxicity was acceptable in most patients, with reversible myelosuppression being the most frequent side effect. Phase III trials of this promising new agent are warranted.

Mitoxantrone: modest activity in a phase II trial in advanced prostate cancer

Thirty-seven patients with metastatic prostate cancer refractory to endocrine therapy were treated in a phase II trial of mitoxantrone. Starting doses were 12 and 10 mg/m2 iv every 21 days for good-risk and poor-risk patients, respectively. Of the 35 evaluable patients, two had objective partial regression and five had stable disease. Response duration ranged from 7 to 17+ months. The drug was very well tolerated by these elderly patients; myelosuppression was the major toxic effect. We conclude that mitoxantrone has modest activity and acceptable toxicity in patients with advanced prostate cancer.

Tumor-derived growth factor increases bone resorption in a tumor associated with humoral hypercalcemia of malignancy

Evidence is presented that a tumor-derived transforming growth factor is responsible for stimulating bone resorption and causing hypercalcemia in an animal tumor model of the hypercalcemia of malignancy. Both conditioned medium harvested from cultured tumor cells and tumor extracts of the transplantable rat Leydig cell tumor associated with hypercalcemia contained a macromolecular bone resorbing factor with the chemical characteristics of a tumor-derived transforming growth factor.

Characterization of insulin regulation of lipid synthesis in MCF-7 human breast cancer cells

Stimulation of lipid synthesis by insulin in MCF-7 human breast cancer cells is characterized by an increase in acetate incorporation into long-chain fatty acids. The effects occurs in the absence of an increase in glucose uptake by the cells, and cannot be explained by a decrease in turnover of cellular fatty acids. Differential substrate experiments as well as direct measurement of enzyme activities indicate that insulin stimulates increases in activity of the first enzyme of the de novo pathway, acetyl CoA carboxylase. [32Pi] incorporation into phospholipids is also stimulated by insulin. Thin layer chromatography reveals five peaks of [32Pi]-labeled phospholipids corresponding in mobility to the following standards: lysophosphatidylcholine, sphingomyelin, phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine. [32Pi] incorporation into each of these peaks is stimulated, although the degree of stimulation varies.

An autopsy study of histologic progression in non-Hodgkin's lymphomas. 192 cases from the National Cancer Institute

Histologic slides were reviewed from 192 autopsies of patients with non-Hodgkin's lymphomas admitted to the National Cancer Institute (NCI) from 1953 to 1975. Each autopsy was classified according to the systems of Rappaport and Lukes-Collins. Comparisons with the initial diagnosis were made. The initial histologic diagnoses of the autopsied population were similar in distribution to other published series of non-Hodgkin's lymphomas. Of the 56 cases which initially demonstrated nodular patterns of growth, the following distribution was found at autopsy: 25%, no lymphoma; 6%, nodular lymphoma; 32%, diffuse histiocytic (large cell) lymphoma (DHL); 21%, diffuse undifferentiated (non-Burkitt's) lymphoma (DUL); and 16%, the remaining diffuse morphologies. Of the 136 patients with initial diagnosis of diffuse lymphoma, the following distributions were observed at autopsy: 20%, no lymphoma; 0%, nodular lymphoma; 31%, diffuse histiocytic (large cell) lymphoma; 12%, diffuse undifferentiated (non-Burkitt's) lymphoma; 9%, Burkitt's tumor; 14%, diffuse poorly differentiated lymphocytic lymphoma; and 14%, the remaining diffuse morphologic types. One hundred and thirty-four cases which were initially diagnosed as follicular center cell type within the Lukes-Collins classification gave the following distribution at autopsy: 21%, no lymphoma; 25%, small noncleaved type; 17%, large noncleaved type; 23%, non-follicular center cell lymphomas (17% immunoblastic B); and the remaining 13% were distributed among the other follicular center cell types. This autopsy review demonstrates the rarity of nodular (follicular) lymphomas at autopsy, and the predominance of the diffuse histiocytic or "transformed" type. This study provides a comparison of the rate of histologic progression of lymphomas in the same patient population at autopsy with a previously published study of progression during life.

Effects of tamoxifen on human breast cancer cell cycle kinetics: accumulation of cells in early G1 phase

We have studied the effects of tamoxifen on the cell cycle kinetics of the endocrine-responsive MCF-7 human breast cancer cells. Tamoxifen inhibits proliferation of MCF-7 cells. The tritiated thymidine labeling index is markedly reduced by tamoxifen, indicating a reduction in the fraction of cells in S phase. Flow cytometry of mithramycin-stained cells reveals that cells accumulate in G1 phase, with a concomitant depletion of S- and G2-M-phase cells with tamoxifen. Mapping of G1-phase cells by morphology of prematurely condensed chromosomes demonstrated that tamoxifen-treated cells accumulate in early G1. These studies indicate that tamoxifen inhibits proliferation of MCF-7 human breast cancer cells by invoking a transition delay early in the G1 phase of the cell cycle.

Anaphylactoid reactions associated with bisantrene infusions

Nine of ninety-three patients receiving Bisantrene on an every three week schedule developed an anaphylactoid reaction with a variety of symptoms. Most reactions occurred in patients who had multiple exposures to Bisantrene. Investigators utilizing Bisantrene in ongoing clinical trials should be aware of this life threatening toxicity.

Multiple estrogen receptor assays in human breast cancer

A review of assay results from more than 6000 patients revealed 232 patients in whom multiple breast cancer specimens were analyzed for estrogen receptor (ER). All assays were performed in a single laboratory. Specimens were considered estrogen receptor positive (ER+) if the ER level was greater than 10 fmol/mg protein and estrogen receptor negative (ER-) if the ER level was less than 3. ER values between 3 and 10 fmol/mg protein were considered borderline. Simultaneous assays were performed in 58 patients with 3% major discordance (i.e., one assay ER- and one assay ER+). Major discordance for sequential biopsies was 19% (16 of 82) when the initial assay was ER+ and 13% (eight of 63) when the initial assay was ER-. (Apparent change from ER- to ER+ status was observed in five of nine patients with primary tumors less than 2 cm in diameter, suggesting that an inadequate amount of tissue may have been submitted for initial ER analysis.) There was no significant relationship between the time interval between sequential biopsies and the rate of discordance. Marked decreases in ER levels and 78% discordance were seen if rebiopsy was performed within 2 months of tamoxifen treatment. When these tamoxifen cases were excluded from the analysis, neither intervening endocrine therapy nor chemotherapy significantly altered discordance rates.

Androgen priming and cytotoxic chemotherapy in advanced prostatic cancer

Hormone manipulation has been standard therapy for metastatic adenocarcinoma of the prostate for many years. Recently cytotoxic drugs have been studied, but their effectiveness has been limited, indicating the need for new therapeutic approaches. Based upon the hypothesis that cytotoxic drugs are most effective against actively proliferating cells, we have designed a clinical pilot study employing cyclical androgen priming to transiently stimulate tumor cells followed by cytotoxic chemotherapy with cyclophosphamide and methotrexate. There were nine responders (43%) out of 21 patients entered in the study, with a median duration of response that has not been reached at 9+ months. Survival was significantly better in responders than in non-responding patients. These results are similar to those of other studies in which chemotherapy was used alone. Chemotherapy toxicity with this schedule was mild. However, the androgen priming frequently resulted in increased bone pain, and there was one episode of spinal cord compression, suggesting that tumor stimulation was achieved. These results demonstrate the need for additional basic studies of the effects of testosterone on tumor cell kinetics before further clinical trials of this approach are initiated.

Steroid hormone receptors and carcinoma of the breast

The estrogen receptor (ER) assay has become a standard practice in the management of advanced breast cancer. Tumors lacking ER respond infrequently to endocrine therapy, whereas response rates of 50-60% are observed in ER+ tumors. Recent studies indicate that the ER status of the primary tumor is a good predictor of the endocrine dependence of metastatic tumors at the time of subsequent relapse. Furthermore, the absence of ER in the primary tumor is an important independent prognostic indicator of higher rate of recurrence and shorter survival. Quantitative analysis of ER and assay of progesterone receptor (PgR) are useful for increasing the accuracy of selecting patients for hormonal therapy; tumors with a high quantitative ER content or those with a positive PgR display the highest objective response rates. Preliminary analysis suggests that the presence of PgR may be the best available tumor marker of hormone dependence.

Combined chemo-hormonal therapy in breast cancer: a hypothesis

Results of treatment for advanced breast cancer have plateaued indicating the need for new treatment approaches. One such approach, combined endocrine therapy and cytotoxic chemotherapy, has had limited success in current clinical trials. This lack of synergism could be due to the effect of endocrine therapy on tumor cell kinetics, which could inhibit the activity of the cytotoxic drug. Proper sequencing of the two treatment modalities may increase the therapeutic ratio.

Adjuvant therapy for stage II, estrogen receptor negative breast cancer

The estrogen receptor (ER) assay provides information which correlates with the proliferative potential, pathology and prognosis for patients with breast cancer. A review of our natural history data correlating ER and axillary node involvement at the time of mastectomy with prognosis allows the identification of a high risk subset of patients with early recurrence and poor survival. Patients with ER negative, stage II disease had a significantly higher recurrence rate, and poorer overall survival was observed in spite of systemic therapy instituted at relapse. Based on this data we initiated a pilot study of intensive adjuvant therapy for women with ER negative, stage II breast cancer. At a median follow-up of 19 months for 39 treated patients, both a disease free and overall survival advantage is apparent for treated patients. Morbidity was low, with no therapy related hospitalizations. We have demonstrated the feasibility of intensive therapy for this high risk group. For a definitive answer the patient resources of a cooperative group will be needed.

Potential and problems with growth of breast cancer in a human tumor cloning system

A human tumor cloning system has been utilized to culture 431 patients' breast cancer specimens. Overall, 288 or 67% of the specimens formed colonies in soft agar. Of the primary lesions 188/260 (72%) formed colonies and 100/171 (58%) of the metastatic lesions formed colonies. The median number of colonies per 500,000 nucleated cells plated was 47 for the primary lesions and 30 for the metastatic lesions. Growth from a variety of metastatic sites ranged from 22% for intradermal lesions to 77% for solid visceral metastases. Methods to increase the number of colonies from a specimen are reported including increasing the number of nucleated cells plated and making a variety of changes in the growth media. None of these methods has had a major impact on colony growth. The antitumor activity of standard anticancer agents such as adriamycin and medroxyprogesterone in the assay is presented. In addition, in vitro results with two new anthracene derivatives demonstrate good antitumor activity for the derivatives. The cloning assay represents a new model for both the basic and clinical studies of human breast cancer.

Antagonism between epidermal growth factor and phorbol ester tumor promoters in human breast cancer cells

It has been suggested that the phorbol ester tumor promoters act via the receptor-effector system for epidermal growth factor (EGF), since they interact with the EGF receptor system and mimic many of the effects of EGF in cultured cells. We have studied the interaction of phorbol esters with the EGF-responsive MCF-7 human breast cancer cell line. Similar to other systems, phorbol esters inhibit EGF binding in MCF-7 cells in a manner paralleling their potency as tumor promoters in mice. The effect is specific for EGF since the membrane binding of insulin is unaffected. Like EGF, the potent phorbol ester 12-O-tetradecanoyl-13-phorbol acetate (TPA) stimulates protein synthesis as indicated by a twofold increase in [(3)H]leucine incorporation into protein after 24 h in TPA. Cell morphology, however, is significantly different with TPA treatment. After 24-48 h in TPA, cells become markedly enlarged with increased cytoplasmic vacuolization and increased membrane microvilli. This is reflected in a fourfold increase in the protein/DNA ratio (control 13.1; TPA 55.9). Furthermore, TPA inhibits cell division in media with or without serum, and prevents growth stimulation by EGF. Low TPA concentrations (1.0 ng/ml) are active, and 10 ng/ml results in maximal inhibition of cell replication. Other phorbol esters inhibit MCF-7 cells relative to their tumor promoting activity in vivo and their ability to inhibit EGF binding in these cells. After 24 h in TPA, incorporation of [(3)H]thymidine into DNA is markedly reduced and the thymidine labeling index falls (33% to 2%) indicating very few S-phase cells. Growth inhibition is reversible by removing TPA from the medium. Similar inhibitory effects are seen with the two other human breast cancer cell lines studied, ZR75-1 and MDA-MB-231. In conclusion, phorbol esters may interact with the EGF receptor domain in MCF-7 human breast cancer cells, but they have distinct effects on cell morphology and growth suggesting alternative pathways of action. The antineoplastic activity of these compounds needs further investigation.

Correlation of primary breast cancer histopathology and estrogen receptor content

We studied the association of estrogen receptor (ER) with several histologic variables that correlate with breast tumor differentiation and with patient prognosis. Contingency table analysis revealed highly statistically significant correlations between ER content and histologic and nuclear grades, tumor necrosis, and the degree of elastosis and lymphoid cell infiltration. ER positive tumors were more likely than ER negative tumors to demonstrate histological evidence of tumor differentiation. All tumors with histologic grade 1 or nuclear grade 1 (best differentiated) were ER positive or borderline positive. Eighty-nine percent of ER negative tumors were histologic grade 3 and 78.4% were nuclear grade 3 (poor differentiation). ER positive tumors were also correlated with absent tumor necrosis, higher elastic content, and absent lymphoid cell infiltration, all features of good differentiation. Medullary carcinomas were frequently (73%) ER negative, but no relationship between ER and other morphologic types of breast cancer or 9 other morphologic variables was found. ER appears to be a biochemical marker for the degree of differentiation of human breast cancer providing a rationale for the observed differences in biological behavior between receptor positive and negative tumors.

The value of estrogen and progesterone receptors in the treatment of breast cancer

The estrogen receptor (ER) assay has become a standard practice in the management of advanced breast cancer. Tumors lacking ER respond infrequently to endocrine therapy, whereas response rates of 50 to 60 percent are observed in ER+ tumors. Recent studies indicate that the ER status of the primary tumor is a good predictor of the endocrine dependence of metastatic tumors at the time of clinical relapse. Furthermore, the absence of ER in the primary tumor is an important independent prognostic indicator of higher rate of recurrence and shorter survival. Quantitative analysis of Er and an assay for progesterone receptor (PgR) are two methods for increasing the accuracy of selecting or rejecting patients for hormonal therapy; tumors with a high quantitative ER content or those with a positive PgR display the highest objective response rates. Preliminary analysis suggests that the presence of PgR may be a better marker of tumor hormone dependence than quantitative ER.

Modern approaches to the treatment of breast cancer

Breast cancer is the most common cause of cancer death in women in this country. Until recently, the traditional treatment has been radical surgery with or without radiation therapy for patients with primary breast cancer, and palliative endocrine therapy followed by chemotherapy for patients with advanced disease. These treatments have met with limited effectiveness in terms of eradicating the disease. Studies in the past decade have given cause for optimism for breast cancer patients. Adjuvant systemic therapy after local treatment appears promising for certain subsets of patients with primary breast cancer. The development of estrogen receptor assays has markedly changed our approach to the disease and improved patient care. Estrogen receptor is an important prognostic factor and is useful in planning appropriate therapy for patients with primary breast cancer as well as those with advanced disease. Further research is urgently needed to improve the dismal survival of certain women with this common malignancy.

Steroid hormone receptors in the management of human breast cancer

Recent insight into the mechanism of steroid hormone receptors in human breast cancer has led to new approaches in treatment strategy. Estrogen receptor (ER) has now replaced clinical criteria in the selection of patients for endocrine therapy. Patients whose tumors do not contain ER should not be subjected to hormonal manipulation. In addition, ER measured on the primary tumor has been found to be an independent prognostic factor for both recurrence and survival. Patients with ER negative primary tumors have a poorer prognosis. This information may be useful in the design and selection of therapy for future adjuvant clinical trials. In metastatic breast cancer, the absolute ER value may provide valuable information regarding endocrine responsiveness. In addition, the measurement of progesterone receptor (PgR) may provide additional insight for predicting with confidence those patients likely to respond.

Nodular histiocytic lymphoma: an aggressive nodular lymphoma with potential for prolonged disease-free survival

Nodular histiocytic lymphoma (NH) is uncommon, and its natural history is not well defined. Of 473 patients with non-Hodgkin's lymphoma, we found 16 (3.4%) with NH. Most patients (13/16) presented with pathologic stage (PS) III or IV disease, including 7 with liver involvement. One patient (PS III) was initially treated with cyclophosphamide alone, and 4 patients received only radiotherapy, and none were long-term survivors. Eleven patients received combination chemotherapy, and 8 achieved complete remission. Only one of these patients relapsed and died at 19 mo; the other 7 continue in complete remission without maintenance therapy with a minimum followup of 4.5 yr. The survival of the entire group of patients with NH is intermediate between that of the other nodular lymphomas and diffuse histiocytic lymphoma. Nine of 16 patients had either a repeat lymph node biopsy during the course of their disease or lymph node examination at autopsy. Lymph node histology in the majority converted to a diffuse, less differentiated subtype of lymphoma. NH has a natural history similar to that of diffuse histiocytic lymphoma and should be approached with the same therapeutic strategy.