Galgo: a bi-objective evolutionary meta-heuristic identifies robust transcriptomic classifiers associated with patient outcome across multiple cancer types

MOTIVATION

Statistical and machine-learning analyses of tumor transcriptomic profiles offer a powerful resource to gain deeper understanding of tumor subtypes and disease prognosis. Currently, prognostic gene-expression signatures do not exist for all cancer types, and most developed to date have been optimized for individual tumor types. In Galgo, we implement a bi-objective optimization approach that prioritizes gene signature cohesiveness and patient survival in parallel, which provides greater power to identify tumor transcriptomic phenotypes strongly associated with patient survival.

RESULTS

To compare the predictive power of the signatures obtained by Galgo with previously studied subtyping methods, we used a meta-analytic approach testing a total of 35 large population-based transcriptomic biobanks of four different cancer types. Galgo-generated colorectal and lung adenocarcinoma signatures were stronger predictors of patient survival compared to published molecular classification schemes. One Galgo-generated breast cancer signature outperformed PAM50, AIMS, SCMGENE and IntClust subtyping predictors. In high-grade serous ovarian cancer, Galgo signatures obtained similar predictive power to a consensus classification method. In all cases, Galgo subtypes reflected enrichment of gene sets related to the hallmarks of the disease, which highlights the biological relevance of the partitions found.

AVAILABILITY AND IMPLEMENTATION

The open-source R package is available on www.github.com/harpomaxx/galgo.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Abstract P5-16-05: Comparative analysis of the immunohistochemical profile of ductal carcinoma in situ to invasive ductal carcinoma

Introduction:

The molecular subtypes have classified invasive breast carcinomas in diverse entities with different clinical behaviors, but the prevalence of these subtypes in ductal carcinoma in situ (DCIS) has not been evaluated in detail. The main objectives of this study were to compare proteomic expression profiles of DCIS and invasive ductal carcinoma (IDC) by immunohistochemistry (IHC), classify them according to the molecular subtypes and evaluate the relationship between the expression of the biological markers and the tumoral grade.

Methods:

We assessed the frequency of expression of ER, PR, HER2, proliferation markers (PCNA or Ki67), Bcl-2 and p53 in 107 DCIS and compared them with the expression of 682 IDC. They were classified according to molecular subtypes. We evaluated the relationship between the expression of these markers and the nuclear and histological grades of DCIS and IDC respectively.

Results

The expression of Bcl-2 and PR was significantly more frequent in the DCIS group (p = 0.0461 and p = 0.0001 respectively). The IDC showed significantly increased values for cell proliferation markers and mutated p53 (p < 0.0001 and p = 0.0062 respectively). The prevalence of ER and HER2 was similar in both groups (p = 0.0912 and p = 0.4686 respectively).

Clinico-pathological parameters and biomarkers expression DCISIDCPN107682 Age (mean)52.75 years55.79 years0.0219Tumoral size (mean)1.62 cm2.23 cm<0.0001Grade 144 (41.12%)95 (13.92%)<0.0001Grade 229 (27.10%)277 (40.61%)0.0076Grade 334 (31.78%)310 (45.45%)0.0086ER positive82 (76.63%)467 (68.47%)0.0912PR positive70 (65.42%)373 (54.69%)0.0461HER2 positive19 (17.78%)101 (14.81%)0.4686Proliferation markers high65 (60.75%)206 (30.21%)<0.0001Bcl-2 positive84 (78.51%)405 (59.38%)0.0001p53 mutated33 (30.84%)307 (45.01%)0.0062

The luminal A subtype was more common in DCIS (p = 0.0003), whereas luminal B no-HER2 and triple negative were more prevalent in IDCs (p = 0.0195 and p = 0.0351 respectively). There were no differences in the frequency of luminal B-HER2 and HER2 positives (p = 0.3279 and p = 1.0000 respectively).

Prevalence of molecular subtypes. DCISIDCPLuminal A46 (43%)172 (25.22%)0.0003Luminal B32 (29.91%)288 (42.23%)0.0195Luminal B-HER2+11 (10.28%)50 (7.33%)0.3279HER28 (7.47%)51 (7.48%)1.0000Triple Negative10 (9.34%)121 (17.74%)0.0351

In relation to nuclear grade of DCIS, no differences were detected with respect to the expression of ER, Bcl-2 and mutated p53 (p = 0.3691, p = 0.8136 and p = 0.3138 respectively). Proliferation markers increased significantly with increasing nuclear grade (p <0.0001). PR was mostly expressed in DCIS grade 1 and HER2 in grade 3, but this was not statistically significant (p = 0.0741 and p = 0.0851 respectively). With regard to histological grade of IDCs, there were a higher frequency of ER, PR, Bcl-2 in grades 1 (p <0.0001). G3 carcinomas showed increased expression of HER2, proliferation markers and mutated p53 (p <0.0001, p <0.0001 and p = 0.0110 respectively).

Conclusions:

The DCIS presents significant differences in tumor subtypes compared with IDC. The lower frequency of triple negative tumors and Luminal B-HER2-, lower expression of mutated p53 and lower degree of proliferation, suggest a less aggressive behavior of DCIS.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-16-05.

Heat shock factor 1 represses estrogen-dependent transcription through association with MTA1

Heat shock factor 1 (HSF1), the transcriptional activator of the heat shock genes, is increasingly implicated in cancer. We have shown that HSF1 binds to the corepressor metastasis-associated protein 1 (MTA1) in vitro and in human breast carcinoma samples. HSF1-MTA1 complex formation was strongly induced by the transforming ligand heregulin and complexes incorporated a number of additional proteins including histone deacetylases (HDAC1 and 2) and Mi2alpha, all components of the NuRD corepressor complex. These complexes were induced to assemble on the chromatin of MCF7 breast carcinoma cells and associated with the promoters of estrogen-responsive genes. Such HSF1 complexes participate in repression of estrogen-dependent transcription in breast carcinoma cells treated with heregulin and this effect was inhibited by MTA1 knockdown. Repression of estrogen-dependent transcription may contribute to the role of HSF1 in cancer.

Predictive value of apoptosis, proliferation, HER-2, and topoisomerase IIα for anthracycline chemotherapy in locally advanced breast cancer

PURPOSE

Laboratory evidence indicates that tumor growth depends on the balance between cell proliferation and cell death, and many anticancer agents may exert their therapeutic effect by decreasing proliferation and increasing apoptosis. Additionally, clinical observations indicate that overexpression of HER-2 or topoisomerase IIalpha (topo IIalpha) may be predictors of better response to anthracyclines in breast cancer. The objective of this study was to determine if proliferation (Ki-67), apoptosis (TUNEL), and expression of HER-2 and topo IIalpha are affected by anthracycline treatment, and if these molecular markers predict anthracycline responsiveness.

EXPERIMENTAL DESIGN

Thirty-three women with primary breast tumors > or =3 cm received either doxorubicin (75 mg/m(2)) or epirubicin (120 mg/m(2)) for 4 cycles before surgery. Clinical response was evaluated after 4 cycles of treatment. Changes in molecular markers were assessed from core needle taken before treatment (D0), at 24-48 h (Dl) and on day 7 (D7) while on treatment, and from the surgical specimen excised on day 84 (D84) after the fourth cycle of chemotherapy.

RESULTS

The overall response rate was 51% (17 of 33 patients), with a 12% complete clinical response rate (4 of 33 patients). There were trends for tumors with higher apoptosis and topo IIalpha at baseline (D0) to be more responsive to anthracyclines, p = 0.1 and p = 0.08, respectively. Median apoptosis increased from D0 to Dl (p = 0.06) while median Ki-67 decreased (p = 0.07). Overall, expression of HER-2 remained stable throughout the chemotherapy administration. By Day 84, topo IIalpha had significantly decreased from baseline in responders, while it increased in non-responders, p = 0.03.

CONCLUSIONS

In human primary breast cancer, anthracycline treatment causes an early increase in apoptosis and a decrease in proliferation. In this pilot study, higher apoptosis and topo IIalphaa levels in primary tumors were associated with greater responsiveness to anthracyclines, and topo IIalpha levels declined in responsive tumors.

Progesterone receptors: their localization, binding activity and expression in the pig oviduct during follicular and luteal phases

Estrogens (E) and progesterone (P) are known to require their respective steroid receptors in order to exert structural and functional effects on the oviduct. Cyclic changes in progesterone receptor (PR) localization in the oviductal tissue of female pigs were determined using an immunohistochemical technique with mouse monoclonal antibody mPRI against PR. The variations observed during the estrous cycle in the progesterone receptor (PR) intensity and proportion between ampulla and isthmus probably reflect different response of these regions to progesterone. Immediately before ovulation, during follicular phase, no staining was observed in either the ampulla or the isthmus stroma. However, a low expression of PR in the epithelium of the ampulla was observed. After ovulation, during luteal phase, PR immunostaining was more intense in the whole oviduct. According to immunohistochemical assays, the binding assays for nuclear and cytosolic PR (PRn and PRc, respectively), by using [3H] R5020 at 4 degrees C for 15 h, also showed a higher specific binding during luteal phase. However, the PR mRNA in the oviduct, analyzed by RT-PCR, showed similar levels at both stages of the estrous cycle. Although this methods could not be quantitative, indicate the possibility that a post-transcriptional control could differentially regulate the PR in the pig oviduct.

Effect of neonatal chronic stress on expression of Hsp70 and oestrogen receptor alpha in the rat oviduct during development and the oestrous cycle

A chronic unpredictable stress model used to produce depressive disorders in adult rats was applied to neonatal rats to investigate whether this type of stress can induce changes in the expression of Hsp70 and oestrogen receptor alpha in the oviduct, as detected by immunohistochemistry. Rats stressed during neonatal development showed changes in the expression pattern of Hsp70. In neonatal control rats, Hsp70-positive cells observed in the isthmus did not show any changes. Moreover, rats exposed to this stress model that reached adulthood had higher expression of Hsp70 in the isthmus (P<0.01) but not in the ampulla during oestrus than did the control rats. In contrast, during dioestrus, no significant changes were noted in adult rats that were stressed during neonatal development or in rats that were stressed in adulthood. These findings indicate that the isthmus is very sensitive to stressful stimuli and that repeated pre-weaning stress can change the expression of heat shock proteins in early and adult life. These subtle changes of expression in the oviduct did not affect the fertility of the rats that reached adulthood or that were mated under unstressed conditions. However, the control animals stressed during adulthood showed a disruption of the oestrous cycle: this finding is not observed in rats stressed during neonatal development that show an attenuated oestrous cycle disruption induced by chronic stress in adulthood. Moreover, there was dissociation between the expression of oestrogen receptor alpha and Hsp70. The amount of oestrogen receptor alpha remained constant in the epithelium of the oviduct in the control and in the stressed rats. Expression of oestrogen receptor alpha was noted in the stroma of the oviduct without the concomitant expression of Hsp70. It is possible that in certain cells and tissues Hsp70 is not necessary for oestrogen receptor alpha to be functional or Hsp70 might be present at very low amounts but is sufficient for the receptor to function.

Helicobacter pylori infection affects the expression of PCNA, p53, c-erbB-2 and Bcl-2 in the human gastric mucosa

OBJECTIVE

Helicobacter pylori infection has been related to gastric carcinogenesis. This association is based on epidemiological data, pathological changes observed in the gastric mucosa, and chemical products from bacteria that may induce damage of DNA. In the present study we examined gastric endoscopic biopsies from patients with chronic gastritis, with and without H. pylori infection, and surgical biopsies from gastric cancer patients to evaluate whether this bacteria may induce changes in the expression of molecular markers associated with carcinogenesis.

PATIENTS AND METHODS

the study involved 57 biopsies from the antral region of the stomach of patients with chronic gastritis and gastric cancer that were analyzed by immunohistochemistry. Molecular markers examined were: PCNA (Proliferating Cell Nuclear Antigen), p53, c-erbB-2, Bcl-2, and p21 H-ras.

RESULTS

PCNA content of epithelial cells was significantly higher in H. pylori infected biopsies. Treatment aimed to eradicate H. pylori decreased the level of PCNA-positive cells in the group of patients that became H. pylori-negative as well as in H. pylori-positive patients. Nuclear p53 expression (used here as a surrogate marker for p53 mutation/inactivation) and c-erbB-2 expression were observed only in the group of patients that remained with the bacteria after treatment. A higher bcl-2 expression in lymphoid cells was observed in H. pylori-positive biopsies, and treatment did not change the expression of this protein. No significant expression of p21 H-ras was observed in the studied biopsies.

CONCLUSION

this study suggests that H. pylori is involved in the induction of molecular changes that might predispose human gastric mucosa cells to pre-neoplastic and neoplastic events.

A silver staining method for single-cell gel assay

The single-cell gel assay (comet assay) is a very useful microelectrophoretic technique for evaluation of DNA damage and repair in individual cells. Usually, the comets are visualized and evaluated with fluorescent DNA stains. This staining requires specific equipment (e.g., a high-quality fluorescence microscope), the slides must be analyzed immediately, and they cannot be stored for long periods of time. Here we describe, using human lymphocytes, some modifications of the silver staining for comets that significantly increase the sensitivity/reproducibility of the assay. This silver staining was compared with fluorescence staining and commercial silver stains. (J Histochem Cytochem 49:1183-1186, 2001)

Immunohistochemical analysis of Ki-67, p21waf1/cip1 and apoptosis in marker lesions from patients with superficial bladder tumours treated with vinorelbine intravesical therapy in a preliminary phase I trial

OBJECTIVE

To investigate Ki-67 and p21Waf1/Cip1 expression and apoptosis, before and after treatment, in tumour biopsies obtained from patients with superficial bladder cancer who underwent vinorelbine intravesical therapy.

PATIENTS AND METHODS

Twenty patients with high-risk superficial bladder cancer (including one or more of the following parameters: tumour diameter > 3 cm, histological grade 3, or multicentric tumours) were treated 1-6 times (weekly) with intravesical vinorelbine (50 mg/mL) instillations. Transurethral tumour marker biopsies were obtained one week before the first instillation of the drug and one week after the last. The biopsies were immunostained for Ki-67 and p21Waf1/Cip1 with monoclonal antibodies, on tissue sections derived from paraffin-embedded samples obtained before and after vinorelbine treatments. In addition, apoptosis was determined using a terminal deoxynucleotidyl transferase-mediated dUTP biotin nick-end labelling (TUNEL) technique.

RESULTS

There were no significant differences in the cell proliferation marker Ki-67 in biopsies taken before or after treatment. However, p21Waf1/Cip1 showed significantly higher expression in biopsies obtained after vinorelbine treatment, with median (range) values of 40 (20-90)% before and 70 (50-80)% after (P < 0.001, paired nonparametric Wilcoxon test). The apoptotic index was significantly higher after vinorelbine therapy, with median (range) values of 0.89 (0.06-3.8)% before and 2.25 (0.17-18.7)% after treatment (P < 0.001, paired nonparametric Wilcoxon test). Despite the brief treatment and few patients there was a clinical response in nine patients, together with low toxicity in all.

CONCLUSION

The intravesical treatment of tumours with vinorelbine affects p21Waf1/Cip1 expression without blocking cell proliferation, although increasing apoptosis. The preliminary results suggest that vinorelbine may be useful for treating superficial bladder tumours, and thus a phase II study is warranted.

Differential anthracycline sensitivity in two related human colon carcinoma cell lines expressing similar levels of P-glycoprotein

Chemosensitivity of the human colon carcinoma HCT-15 cell line to 4'-epidoxorubicin proved to be 100-fold higher than that of its variant HCT-15 EDR. Confocal scanning microscopy showed significant less drug accumulation in HCT-15 EDR. A 2-fold increase in hsp27 expression was found in HCT-15 EDR, with no alteration in hsp70. The expression of the drug exporter Pgp was similar in both cell lines, despite the lower drug accumulation shown by HCT-15 EDR in respect to HCT-15. Other molecules implicated in the acquisition of enhanced chemoresistance or a more active Pgp variant present in HCT-15 EDR, could explain the phenomenon.

Constitutive expression of heat shock proteins hsp25 and hsp70 in the rat oviduct during neonatal development, the oestrous cycle and early pregnancy

Certain heat shock proteins are regulated by steroid hormones and are associated with oestrogen receptor function in reproductive tissues, indicating that these proteins have a role during implantation, decidualization and placentation. In the present study, the expression of hsp25, hsp70 and oestrogen receptor alpha were examined by immunohistochemistry in oviducts from rats during neonatal development, the oestrous cycle and during early pregnancy. Oestrogen receptor alpha was the first protein observed in the neonatal oviduct, and its expression preceded that of hsp70 and hsp25. Although these heat shock proteins have been associated with the oestrogen receptor, this study showed that during early development of the oviduct, the receptor protein was not associated with the concomitant expression of hsp25 and hsp70. However, these heat shock proteins were expressed when oviductal cells became differentiated. In the adult oviduct, hsp70 was more abundant than hsp25, moreover, there were no significant modifications in expression of hsp25 during the oestrous cycle. In contrast, the expression of hsp70 was significantly higher in epithelial cells during dioestrus, when the maximum amount of oestrogen receptor alpha was also observed. Therefore, the present study shows that hsp70, but not hsp25, is an oviductal protein modulated by the oestrous cycle and that it is a protein marker for specific phases of the oestrous cycle. In addition, hsp70 was more responsive to the hormonal changes in the infundibulum and ampullar regions of the oviduct. During early pregnancy, hsp25 expression was downregulated (unlike in the endometrium), whereas hsp70 was relatively abundant in the oviduct. hsp70 was observed in all functional segments of the oviduct during pregnancy, indicating that in the oviduct, this protein is modulated by oestrogens and progesterone and possibly by other pregnancy-related hormones.

Constitutive expression of heat shock proteins hsp25 and hsp70 in the rat oviduct during neonatal development, the oestrous cycle and early pregnancy

Certain heat shock proteins are regulated by steroid hormones and are associated with oestrogen receptor function in reproductive tissues, indicating that these proteins have a role during implantation, decidualization and placentation. In the present study, the expression of hsp25, hsp70 and oestrogen receptor alpha were examined by immunohistochemistry in oviducts from rats during neonatal development, the oestrous cycle and during early pregnancy. Oestrogen receptor alpha was the first protein observed in the neonatal oviduct, and its expression preceded that of hsp70 and hsp25. Although these heat shock proteins have been associated with the oestrogen receptor, this study showed that during early development of the oviduct, the receptor protein was not associated with the concomitant expression of hsp25 and hsp70. However, these heat shock proteins were expressed when oviductal cells became differentiated. In the adult oviduct, hsp70 was more abundant than hsp25, moreover, there were no significant modifications in expression of hsp25 during the oestrous cycle. In contrast, the expression of hsp70 was significantly higher in epithelial cells during dioestrus, when the maximum amount of oestrogen receptor alpha was also observed. Therefore, the present study shows that hsp70, but not hsp25, is an oviductal protein modulated by the oestrous cycle and that it is a protein marker for specific phases of the oestrous cycle. In addition, hsp70 was more responsive to the hormonal changes in the infundibulum and ampullar regions of the oviduct. During early pregnancy, hsp25 expression was downregulated (unlike in the endometrium), whereas hsp70 was relatively abundant in the oviduct. hsp70 was observed in all functional segments of the oviduct during pregnancy, indicating that in the oviduct, this protein is modulated by oestrogens and progesterone and possibly by other pregnancy-related hormones.

Molecular markers for predicting response to tamoxifen in breast cancer patients

Tamoxifen is one of the most effective treatments for breast cancer. Standard practice is to select patients who are likely to respond to this therapy through the evaluation of estrogen receptor (ER) and progesterone receptor (PR) in the primary tumor tissue. Over the past 25 yr that physicians have been using ER determination to guide tamoxifen use, numerous studies have demonstrated that this molecular marker is useful in predicting benefit from tamoxifen. ER has been analyzed for many years using ligand-binding assays. However, current practice involves the use of immunohistochemical-based assays to detect ERalpha Immunohistochemistry (IHC) has several advantages. For example, IHC evaluates tumor cell heterogeneity, can be used to study small samples, is less expensive, and allows direct correlation with multiple histopathological tumor features and other molecular markers. PR, an estrogen-responsive protein, can also be useful in predicting response to tamoxifen in specific clinical situations. In recent years, several other markers of tamoxifen response have been examined, including: pS2 (another estrogen-regulated protein), heat-shock proteins 27 and 70, bcl-2 protein, c-erbB-2 (HER-2/neu) oncoprotein, and mutated p53 tumor suppressor protein. In this article, we present an analysis of the data on these new molecular markers. Overall, from numerous studies, the data indicate that in addition to ERalpha bcl-2 is a potential candidate to help further improve our ability to predict response to tamoxifen. ER and bcl-2 are the most useful molecular markers to better identify breast cancer patients who will respond to tamoxifen and who will have prolonged survival.

Improved detection of apoptotic cells using a modified in situ TUNEL technique

We are in the process of assessing the response of cancer tissues to chemotherapy, evaluating, among other points, the proportion of cancer cells undergoing apoptosis. However, the apoptotic index obtained with the original TUNEL technique was lower than that obtained by evaluation of apoptosis on H&E-stained sections. Here we describe a small modification of the TUNEL technique that significantly increases the sensitivity of the assay. In the nonmodified TUNEL technique, a digoxigenin-labeled probe is detected using a direct peroxidase-conjugated system, whereas here we report the advantage of using a streptavidin-biotin-immunoperoxidase system. This, in conjunction with pretreatment of tissue sections with proteinase K and microwave irradiation, improved the detection of apoptotic cells.

c-erbB-2 (HER-2/neu) protein and drug resistance in breast cancer patients treated with induction chemotherapy

Expression of c-erbB-2 protein has been associated with poor prognosis and poor response to chemotherapy in breast cancer patients. In the present prospective study, we have analyzed whether c-erbB-2, p53 and P170 proteins may be determinants of tumor resistance in locally advanced breast cancer patients treated with induction chemotherapy. Biopsies (n = 60) were examined by immuno-histochemistry; in 62% of cases core or incisional biopsies were taken before drug administration, allowing comparison in paired biopsies of the cytological and molecular changes induced by treatment Sixty percent of the patients received relatively high doses of FAC or FEC (5-fluorouracil, doxorubicin or epirubicin and cyclophosphamide), and 40% received relatively high doses of doxorubicin or epirubicin alone. No significant changes were observed in the molecular markers studied following chemotherapy; in the few biopsies where changes appeared, the changes did not exhibit any significant or similar trend. For 30 of the patients who received FAC/FEC treatment, follow-up reached a median of 34 months. In these cases, neither the clinical (reduction in tumor size) nor the histological (evaluated after neoadjuvant chemotherapy) responses showed statistically significant differences between the patients who developed distant metastases and the disease-free patients. c-erbB-2 was over-expressed in 50% of patients who developed distant metastases vs. 7% of the disease-free patients. Disease free survival (DFS) curves between c-erbB-2-positive and c-erbB-2-negative patients were statistically significant. No correlation between p53 or P170 expression with DFS was found. Our results suggest that c-erbB-2 protein expression is associated with development of distant metastases in breast cancer patients treated with relatively high doses of anthracyclines in induction chemotherapy.

Integration of estrogen and progesterone receptors with pathological and molecular prognostic factors in breast cancer patients

In this study we have examined biopsies from women with localized primary breast cancer to investigate the prognostic performance of estrogen receptors (ER) and progesterone receptors (PR) for estimating the metastatic probability of the patients, and to explore whether discrimination gets better by combining clinicopathological and other molecular parameters into a score. This prospective study involved 205 patients with a median follow-up of 5 y. Among the evaluated clinicopathological data were: patient's age; tumor size; axillary lymph node involvement; and tumor grade. The most representative tumor samples were derived to a single laboratory for immunohistochemical evaluation of the following molecular markers: ER, PR, proliferating cell nuclear antigen (PCNA), p53 protein product, erbB-2 (HER-2/neu) oncoprotein, and P170 glycoprotein (mdrl gen product). Distant metastases (study endpoint) appeared in 19.5% (40/205) of the patients, most of these patients presented a mixture of poor, regular and good prognostic factors. Disease-free survival analysis procedures (Kaplan-Meier method) identified tumor size, axillary lymph node involvement, tumor grade, receptor status, PCNA, p53, erbB-2 and P170 as useful prognostic factors. Proportional hazard regression analysis (Cox) identified in order of importance erbB-2, tumor size, receptors status, tumor grade and PCNA as useful prognostic factors. To facilitate the evaluation of the prognostic factors, a practical and simple score system was derived. A high pathological score identified 65% of the patients that developed distant metastases, while a high molecular score was obtained in 57% of patients with metastatic disease. There was a significant improvement in the diagnosis of probability of being with distant metastases when the pathological score was combined with the molecular score, 82% of the patients with distant metastases showed an elevated combined score. Validation of this scoring system will need further larger studies (validation set as opposed to the training set used in the present study). Due to the complexity of events in cancer, the evaluation of a combination of prognostic factors should be of value to clinicians to make a more objective estimate of the prognosis of individual breast cancer patients.

Heat shock protein expression and drug resistance in breast cancer patients treated with induction chemotherapy

Heat shock proteins (Hsps) are induced in vitro by several cytotoxic drugs; in human breast cancer cells these proteins appear to be involved in anti-cancer drug resistance. The present report was designed to analyze whether chemotherapy affects in vivo the expression of Hsp27, Hsp70, Hsc70 and Hsp90 in breast cancer patients treated with induction chemotherapy and whether these proteins may be determinants of tumor resistance to drug administration. We have analyzed 35 biopsies from breast cancer patients treated with induction chemotherapy. Expression of the Hsps in the tumors was compared with (i) histological and clinical responses to chemotherapy, (ii) tumor cell proliferation measured by proliferating cell nuclear antigen (PCNA) immunostaining and nucleolar organizer regions (AgNORs) staining and (iii) the expression of estrogen and progesterone receptors. We also compared disease-free survival (DFS) and overall survival (OS) with the expression of the Hsps studied. After chemotherapy, nuclear Hsp27 and Hsp70 expression was increased and Hsp70 and Hsc70 cytoplasmic expression was decreased. A high nuclear proportion of Hsp70 in tumor cells (>10%) correlated significantly with drug resistance. We also observed that patients whose tumors expressed nuclear or a high cytoplasmic proportion (>66%) of Hsp27 had shorter DFS. The combination of Hsp27 and Hsp70 levels showed a strong correlation with DFS. Neither the cellular proliferation nor the levels of steroid receptors showed any significant difference before or after drug administration or during follow-up of patients. Our results suggest that Hsp27 and Hsp70 are involved in drug resistance in breast cancer patients treated with combination chemotherapies.

Serological detection of heat shock protein hsp27 in normal and breast cancer patients

Heat shock protein Mr 27,000 (hsp27) is found in many human breast cancer cells and tissues; its expression is associated with the presence of estrogen receptors, lower cell proliferation, and resistance to certain chemotherapies. The purpose of this study was to assess whether hsp27 may be present in sera from women with primary breast cancer and to know whether autoantibodies to hsp27 may be found in these patients. The study was performed by Western blot analyzing sera from 42 normal premenopausal women, 20 normal postmenopausal women, and 36 breast cancer patients. hsp27 was clearly detected in sera by immunoblotting but only after immunoprecipitation. The mean hsp27 levels in cancer patients were higher than in the control patients; however, 66% of the breast cancer patients showed hsp27 within the normal range, indicating low sensitivity. Moreover, cancer patients with metastatic disease did not show significantly higher hsp27 levels than cancer patients without metastases. Serum hsp27 levels did not correlate with the hsp27 levels in tumor tissues detected by immunohistochemistry. Elevated CA 15-3 levels were not associated with high hsp27 values. Autoantibodies against hsp27 were not detected by immunoblotting in normal sera and in sera from breast cancer patients. As a consequence, serological determination of this biomarker is unlikely to be of utility in the detection and follow-up of breast cancer patients.

Heat shock proteins hsp27 and hsp70: lack of correlation with response to tamoxifen and clinical course of disease in estrogen receptor-positive metastatic breast cancer (a Southwest Oncology Group Study)

In this study, we tested the hypothesis that heat shock proteins (hsps) 27 and 70 are associated with clinical resistance to tamoxifen. hsp27 is, like progesterone receptor, an estrogen-regulated protein. hsp70 is also of interest because of its interaction with estrogen receptors and because hsp70 is a component of the molecular chaperone machinery functioning in the assembly and trafficking of steroid receptors. In addition, hsps in general help protect cells against noxious stimuli and stress, and their expression has been linked to drug resistance. The study involved 205 tumors from estrogen receptor-positive tamoxifen-treated breast cancer patients with metastatic disease. All patients received daily tamoxifen as initial therapy for metastatic disease. The study began in 1982, and follow-up is now 9 years. hsp27 and hsp70 were detected by immunohistochemistry and scored according to the nuclear and/or cytoplasmic content. Expression of hsp27 or hsp70 was unrelated to estrogen receptor content, progesterone receptor content, menopausal status, age, and presence of visceral disease. Cytoplasmic and nuclear hsp27 positivities were weakly and inversely related to each other (P = 0.05). There was a significant association between cytoplasmic hsp27 and cytoplasmic hsp70 content (P < 0.001), as well as between nuclear hsp70 and nuclear hsp27 content (P = 0.001). Cytoplasmic and nuclear hsp70 were also associated (P = 0.02). However, increased hsp27 and hsp70 expression (nuclear or cytoplasmic) was not significantly associated with response to tamoxifen, time to treatment failure, or survival. Thus, this study clarifies the lack of clinical utility of hsp27 and hsp70 in predicting the response to tamoxifen in an estrogen receptor-positive breast cancer population.

HER-2 expression and response to tamoxifen in estrogen receptor-positive breast cancer: a Southwest Oncology Group Study

HER-2/neu is a growth factor receptor, the expression of which has been associated with a more aggressive breast tumor biology and resistance to some types of chemotherapy. Preliminary laboratory and clinical data have led to claims that HER-2/neu expression is also associated with resistance to tamoxifen. Therefore, to test the hypothesis that HER-2/neu expression is associated with a poorer response to tamoxifen, a shorter time to treatment failure (TTF), and worse survival in estrogen receptor (ER)-positive metastatic breast cancer, we examined 205 paraffin-embedded blocks of tumors from patients enrolled on Southwest Oncology Group 8228 for HER-2/neu expression. Tumors were ER positive (ER level > 3 fmol/mg cytosolic protein in either primary tumors or metastases), and patients had not received any prior therapy for metastatic disease. All patients were treated with daily tamoxifen. The study began in 1982, and median follow-up of patients who are still alive is now 9 years. Membrane staining for HER-2/neu was evaluated by immunohistochemistry using antibody TAB 250 and was scored according to the proportion of cells staining positive; tumors were deemed positive if > 1% of the cells stained for HER-2/neu. HER-2/neu positivity was associated with lower ER values (P = 0.04) and low bcl-2 (P = 0.01). HER-2/neu positivity was not significantly associated with response rate (negative versus positive, 57 versus 54%; P = 0.67), TTF (median, 8 versus 6 months; P = 0.15), or survival (median, 31 versus 29 months; P = 0.36). There was also no significant evidence of a progressive relationship between an increasing proportion of cells expressing HER-2/neu and a shorter TTF or survival. HER-2/neu expression in ER-positive metastatic breast cancer is not significantly associated with a poorer response to tamoxifen or a more aggressive clinical course. Earlier suggestions to the contrary may have been due to failure to rigorously exclude ER-negative tumors, which are much less likely to respond to tamoxifen and more likely to have high HER-2/neu levels.

Heat shock proteins and cell proliferation in human breast cancer biopsy samples

Human breast cancers may overexpress certain heat shock protein (hsp) family members, proteins which are involved with cell proliferation and differentiation as well as with disease prognosis and drug resistance. Here, we have studied the relationship between the expression of two hsps (hsp27 and hsp70) and the proliferative activity of tumor cells in 40 biopsies from breast cancer patients. Twenty of these tumors were selected for a detailed colocalization study. Immunocytochemistry was done using specific antibodies against hsp27 and hsp70. Cell proliferation was studied analyzing the expression of proliferating cell nuclear antigen (PCNA) (late G1, S, and G2 phases of the cell cycle) and the number of silver-staining nucleolar organizer regions (AgNORs) (G1 phase). The colocalization study revealed a statistically significant inverse correlation between hsp27 expression and cell proliferation in 16/19 (84%) of the cases evaluated by PCNA immunostaining, and in 11/16 (69%) of the cases evaluated by AgNORs. In contrast, a statistically significant positive correlation between hsp70 expression and elevated cell proliferation was seen in almost 85% of the cases evaluated by PCNA staining, and in almost 50% of the cases evaluated by AgNORs. Moreover, in 22% (9/40) of the breast cancer samples examined, hsp70 was clearly associated with the mitotic spindle. A Western blot analysis revealed that hsp70 was coprecipitated with taxol-polymerized tubulin. The association of hsp70 with the mitotic spindle was not clearly noted in lung carcinoma samples (N = 20) or in normal cells displaying elevated mitotic activity. These studies thus demonstrate that in a significant percentage of clinical breast cancers hsp27 overexpression is inversely correlated with cell proliferation, while hsp70 is clearly associated with the mitotic spindle and cell proliferation. These results add evidence to the concept that in human breast cancers hsp27 may be involved in cell growth arrest and increased differentiation while, in contrast, hsp70 may be involved in cell proliferation; further studies will be necessary to elucidate these possible cause-and-effect relationships.

Estrogen receptors and cell proliferation in breast cancer

Most of the actions of estrogens on the normal and abnormal mammary cells are mediated via estrogen receptors (ERs), including control of cell proliferation; however, there are also alternative pathways of estrogen action not involving ERs. Estrogens control several genes and proteins that induce the cells to enter the cell cycle (protooncogenes, growth factors); estrogens also act on proteins directly involved in the control of the cell cycle (cyclins), and moreover, estrogens stimulate the response of negative cell cycle regulators (p53, BRCA1). The next challenge for researchers is elucidating the integration of the interrelationships of the complex pathways involved in the control of cell proliferation. This brief review focuses on the mechanisms of estrogen action to control cell proliferation and the clinical implications in breast cancer. (Trends Endocrinol Metab 1997;8:313-321). (c) 1997, Elsevier Science Inc.

bcl-2, p53, and response to tamoxifen in estrogen receptor-positive metastatic breast cancer: a Southwest Oncology Group study

PURPOSE

To test the hypothesis that high bcl-2 expression and accumulation of p53 protein, both of which should inhibit apoptosis, are associated with a poorer tamoxifen response and a more aggressive clinical course in estrogen receptor (ER)-positive metastatic breast cancer.

METHODS

A total of 205 paraffin-embedded tumor blocks were evaluated for nuclear p53 (a marker of p53 inactivation) and cytoplasmic bcl-2 by immunohistochemistry (IHC). All patients received tamoxifen as initial therapy for metastatic disease. The study began in 1982 and follow-up duration of the 24 patients last known alive is 8 years.

RESULTS

Response to tamoxifen and time to treatment failure (TTF) were not significantly associated with p53 status, although patients with higher p53 had a worse survival (P = .008; median, 36 v 20 months). Higher bcl-2 expression was associated with higher levels of ER (P = .02), better response to tamoxifen (62% v 49%; P = .07), longer TTF (median, 9 v 5 months; P = .002), and better survival (median, 40 months v 25 months; P = .009). In multivariate analyses, including ER, progesterone receptor (PgR), and p53, high bcl-2 remained significantly associated with a longer TTF (P = .007) and survival (P = .07). p53 status was a significant factor for shorter survival (P = .05), but not for TTF (P = .61).

CONCLUSION

p53 status, as determined by IHC is not significantly associated with response to tamoxifen, although tumors with altered p53 protein are inherently more aggressive. Contrary to expectation, high bcl-2 identifies a relatively indolent phenotype of ER-positive metastatic breast cancer, in which patients experience a better clinical response to tamoxifen and a longer survival.

Estrogen receptors, progesterone receptors, and cell proliferation in human breast cancer

The breast is a target organ for estrogens and progesterone. These hormones control several functions of the normal and abnormal mammary epithelium including cell proliferation. Most of the actions of estrogens and progesterone are mediated via specific steroid receptors, and one would expect that proliferating cells should contain estrogen receptors (ER) and/or progesterone receptors (PR). However, the correlation between receptor expression and cell proliferation is still controversial. In the present study we have examined 29 human breast cancer samples; in 17 of them we evaluated the simultaneous ER and PR localization with that of proliferating cell nuclear antigen (PCNA) and silver-stained nucleolar organizer regions (AgNORs) in a cell-by-cell study. We found that in almost 50% of the tumor biopsies examined, the cells expressing ER were significantly associated with elevated cell proliferation. In another group (38%) there were not significant differences between ER expression and cell proliferation. In only one of the samples (6%) the cells expressing ER showed lower cell proliferation. The study also revealed that in 44% of the tumors the PR expressing cells were associated with elevated cell proliferation. In a second group the PR expression was not significantly associated with cell proliferation (33% of the cases). Finally, in 22% of the samples the cells carrying PR showed lower cell proliferation. We also detected lower ER immunoreactivity in 30% of the breast cancer biopsies with one of the monoclonal antibodies against ER (antibody 1D5 directed against the A/B domain). This group of tumors was PR-negative (or very weakly positive) and had high proliferation. The presence of tumors with 'abnormal' ER proteins and displaying ER/PR significantly associated with elevated cell proliferation could have implications in human breast cancer treatment.

The small heat shock protein HSP27 is not an independent prognostic marker in axillary lymph node-negative breast cancer patients

Heat shock protein 27 (hsp27) belongs to the family of heat shock proteins and is thought to be involved in thermotolerance, cell proliferation, drug resistance, and chaperone processes. The aim of this study was to investigate whether hsp27 levels are correlated with clinical outcome in axillary lymph node-negative breast cancer patients. We describe a Western blot study measuring hsp27 levels in 425 patients and an immunohistochemistry (IHC) study analyzing 788 patients. Results obtained by both methods were concordant. Univariate survival analysis was performed considering hsp27 either as an optimally dichotomized variable or as a continuous variable. Additional data include age at biopsy, tumor size, estrogen receptor (ER) and progesterone receptor status, tumor ploidy and percentage of cells in S phase, and adjuvant therapy. hsp27 levels correlated positively with ER status (P = 0.0001 in Western blot and IHC study), progesterone receptor status (P = 0.0001 in Western blot and IHC study), and aneuploidy (Western blot study, P = 0.0012; IHC study, P = 0.0004) but not with tumor size (Western blot study, P = 0.69; IHC, P = 0.53) or S phase (Western blot study, P = 0.19; IHC study, P = 0.38). Overall, there was no relationship between hsp27 expression and disease-free survival (Western blot study, P = 0.70/0.54; IHC, P = 0.47/0.30) or overall survival (Western blot study, P = 0.16/0.15; IHC, P = 0.46/0.78). Exploratory subset analyses defined by ER status and use of adjuvant treatment indicated that in ER+/untreated patients, high hsp27 levels correlated modestly with shorter disease-free survival (Western blot, P = 0.04/0.04; IHC, P = 0.11/0. 03). hsp27 is not a useful prognostic marker for the clinic in axillary lymph node-negative patients. However, the finding of modest prognostic value of hsp27 in the subgroup of ER+/untreated patients raises new questions about the biological function of hsp27 in breast cancer.

Expression of heat shock protein 25,000 in rat uterus during pregnancy and pseudopregnancy

In previous studies, we found that the human estrogen-regulated heat shock protein (hsp) 27 (human homologue of rat hsp25) is modulated in the endometrium during the different phases of the menstrual cycle and that it is present in endometrial predecidual cells and in decidual cells attached to the placenta. In the present report, we describe the cell type-specific pattern of hsp25 expression in the rat uterus during the periimplantation period as well as during early and late decidualization and placentation. The hsp25 expression pattern was also analyzed in pseudopregnant rats with deciduomas. Immunocytochemistry was performed with an antibody generated against a chimeric hybrid protein containing the N-terminal of the murine hsp25 and the C-terminal of the human hsp27. During pregnancy at the time of implantation, hsp25 was expressed in the endothelial cells of the endometrial vessels and in the luminal epithelium of the antimesometrial region. As pregnancy advanced, hsp25 appeared in predecidual/decidual cells close to the implantation region and then expanded to the mesometrial region. This expression pattern was very similar during pseudopregnancy. Hsp25 was strongly expressed in trophoblastic giant cells beginning on Day 11 of gestation; less expression was noted in the junctional and labyrinth zones of the chorioallantoic placenta (in some cells lining the vascular spaces). In all the disparate cell types that expressed hsp25, the presence of the protein did not correlate with cell proliferation or with apoptosis but with the state of differentiation. Some placental PRL-family members with molecular weights similar to that of hsp25 are also present in antimesometrial decidua and in differentiated trophoblast giant cells; therefore, in this study we eliminated the possibility that our antibody was recognizing prolactin. We also determined that the hybrid hsp25/27 protein did not bind prolactin receptors, and noted that the hsp25 immunostaining pattern was not identical to that of decidual prolactin. In conclusion, the striking cell type-specific timing of hsp25 expression points to hsp25 as a molecule that is important during the implantation, decidualization, and placentation processes.

Growth hormone-releasing hormone in testicular interstitial and germ cells: potential paracrine modulation of follicle-stimulating hormone action on Sertoli cell function

GH-releasing hormone (GHRH) is present in the interstitial and germ cells of the rat testis. In previous studies we found that GHRH is secreted from rat adult Leydig cells, in which it stimulates basal and LH-induced cAMP formation and steroidogenesis. In other studies cAMP production in Sertoli cells was found to be stimulated by GHRH. In the present report, we describe a potential paracrine action of GHRH in the Sertoli cell, with stimulation of cAMP formation in cultured adult and pubertal Sertoli cells. GHRH increased FSH-stimulated cAMP production in adult and pubertal cultures in a time-dependent manner. GHRH stimulation of basal and FSH-induced extracellular cAMP formation was more prominent in pubertal than in adult cultures. Immunocytochemical studies demonstrated the presence of GHRH-like immunoreactivity in rat interstitial cells from day 4 to adult life and in the acrosomal region of early and intermediate spermatids at stages III-VI of the seminiferous epithelium cycle. Immunoreactive GHRH was not observed in late spermatids and mature sperm or in Sertoli cells at any age. These results indicate that GHRH acts synergistically with FSH to promote cAMP production in Sertoli cells in culture. Testicular GHRH of Leydig and germ cell origin may be an important paracrine regulator of Sertoli cell function. Alternatively, GHRH present in germ cells may exert stage-specific intracrine functions.

Serotonin secretion from rat Leydig cells

In rat Leydig cells, serotonin (5HT) binds to 5HT2 receptors and stimulates the secretion of CRF which in turn acts as an inhibitor of gonadotropin-induced cAMP formation and androgen production. In the present study we defined the regulation of 5HT secretion in cultured Leydig cells. Adult Leydig cells secreted considerable quantities of 5HT (100-150 pg/10(6) cells per 10 min). The release of 5HT was acutely stimulated by hCG (ED50, 1.1 pM) with maximal stimulation at 10 pM hCG (160%). Forskolin also increased (+220%) 5HT release from cultures (ED50, 50 nM) while TPA was much less effective (+20%), indicating a major role for cAMP in gonadotropin-induced 5HT release. This was confirmed by the finding that 8-Br cAMP (1 mM) was an effective stimulus of 5HT release (+360%). Similar increases of 5HT release by hCG were observed in the absence of extracellular Ca2+. However, ionomycin was a potent stimulus of 5HT release, indicating that elevation of cytoplasmic [Ca2+] could also induce amine secretion. The 5HT content of Leydig cells ranged from 300 to 350 pg/10(6) cells, and decreased during stimulation of 5HT release. Also, immunohistochemical studies revealed specific staining of 5 HT in interstitial cells of the adult rat testis. These studies demonstrated that rat Leydig cells contain and secrete 5HT, and that 5HT release is stimulated by gonadotropin acting primarily through a cAMP-mediated mechanism.

Steroid receptors and heat-shock proteins in patients with primary biliary cirrhosis

Primary biliary cirrhosis has a definite female preponderance. Increased estrogen levels have been found in patients with this disease; however no studies indicate the status of sex hormone steroid receptors in primary biliary cirrhosis patients. In this study the occurrence and distribution of estrogen receptors, progesterone receptors and androgen receptors in liver biopsy specimens from patients with primary biliary cirrhosis were examined and compared with these receptors in the normal liver. In addition, three heat-shock proteins associated with steroid receptors (90 kD, 70 kD and 27 kD) were examined. All of the receptor proteins were detected on immunocytochemical study using specific receptor antibodies; monoclonal and polyclonal antibodies were also used to detect the heat-shock proteins. Normal bile duct epithelial cells displayed low-to-moderate amount of estrogen receptors and abundant 90- kD, 70- kD and 27-kD heat-shock protein expression, whereas normal hepatocytes showed moderate estrogen receptor and 90-kD heat-shock protein and high 70-kD heat-shock protein expression. Expression of 70-kD heat-shock protein was due mainly to the constitutive form of this protein (hsc72). In patients with primary biliary cirrhosis, significant increases in estrogen receptor and 90-kD heat-shock protein content were seen in bile duct cells and in hepatocytes. Levels of 27-kD heat-shock protein were also increased in some of the primary biliary cirrhosis biopsy specimens. The expression of progesterone receptor and androgen receptor was very low in normal and primary biliary cirrhosis bile duct cells and hepatocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of short-term tamoxifen administration in patients with invasive cervical carcinoma

Cervical cancer is not considered a hormone-responsive tumor in spite of the presence of estrogen receptors (ER) and progesterone receptors (PgR) in some of them. Endocrine treatments have not achieved clinical responses, however, tamoxifen has been reported to induce PgR and to inhibit cell growth of many cervical carcinoma cell lines. In this study we investigated whether tamoxifen administration affects the histopathological characteristics of cervical cancer and the expression of ER, PgR, HER-2/neu and p53 protein. Nineteen patients with invasive cervical cancer free of previous treatments were studied. The triphenylethylene antiestrogen tamoxifen was given orally during 10 days (20 or 40 mg/day). Pre- and post-tamoxifen biopsies were evaluated using slides stained with hematoxylin and eosin and immunostained (ER, PgR, HER-2/neu, p53, PCNA, keratin, heat shock protein 27,000 daltons). Estrogen receptors were present in 37% and PgR in 16% of the biopsies from untreated patients. Only one case that was PgR-negative before tamoxifen administration showed weak PgR-positivity following antiestrogen administration. No obvious changes were observed in ER, HER-2/neu and p53 proteins. A statistically significant decrease in the number of mitotic figures was obtained in 16% (3/19) of the post-tamoxifen biopsies and two of them showed higher differentiation. The results showed that tamoxifen did not induce changes in estrogen-regulated proteins in cervical cancer. However, the data showed that certain cervical carcinomas had changes in their proliferation and differentiation levels following tamoxifen administration. These findings suggest that tamoxifen may affect some cervical cancer tissues by a hormone-independent mechanism(s).

Biological and clinical implications of heat shock protein 27,000 (Hsp27): a review

Heat shock and other environmental and pathophysiologic stresses stimulate synthesis of heat shock proteins (Hsps). These proteins enable the cell to survive and recover from stressful conditions by as yet uncompletely understood mechanisms. Hsp27 is an important small Hsp (molecular weight, 27,000) found in human cells--both cancer cells and normal cells. This protein, besides its putative role in thermotolerance, is of special clinical interest because of recent data suggesting it may also play a role in drug resistance. In adults, Hsp27 is found particularly in several cell types such as breast, uterus, cervix, placenta, skin, and platelets. Although low-molecular-weight (small) Hsps have been found to be involved in embryogenesis of Xenopus and Drosophila, they have not been detected in human fetal organs. Regulation of expression of the Hsp gene (also known as HSPB1) has been considered a paradigm of gene regulation and is actively being studied in both prokaryotes and eukaryotes. In prokaryotes, the major Hsp genes are transcriptionally regulated by positively and negatively acting transcription factors. In eukaryotes, the genes encoding Hsps contain a regulatory DNA motif (inverted repeats of the pentameric sequence nGAAn) known as the heat shock element. Hsp27 may function as a molecular chaperone and in signal transduction pathways of different cell regulators, and Hsp27 and other Hsps may be active in development of resistance to stressful conditions and agents including cytotoxic drugs. Study findings indicate that some but not all estrogen-positive breast cancers express Hsp27, and overexpression of Hsp27 has been associated with both good and poor prognosis. In endometrial carcinomas, the presence of Hsp27 is correlated with the degree of tumor differentiation as well as with the presence of estrogen and progesterone receptors. Studies suggest, however, that detection of Hsp27 should not be considered to be a method for identifying hormone-responsive tumors or detecting estrogen receptors. Hsp27 seems to be a biochemical marker of estrogenic endometrial response. In patients with cervical cancer, Hsp27 is predominantly expressed in well-differentiated and moderately differentiated squamous cell carcinomas. In addition, expression of Hsp27 seems to be a negative prognostic factor for gastric cancer. Different isoforms of Hsp27 have been found in lymphoid tissue of patients with acute lymphoblastic leukemia, and the protein has also been associated with viral infections. These aspects are summarized and discussed in the present review.

Estrogen receptor, progesterone receptor, and HER-2/neu protein in breast cancers from pregnant patients

BACKGROUND

Because the occurrence of breast cancer during pregnancy is uncommon and because the high levels of estrogens and progestins associated with pregnancy could cause false-negative results from ligand binding assays (LBA), the actual incidence of steroid hormone receptor positivity in tumors from this subset of women is unclear.

METHODS

Estrogen receptor (ER) and progesterone receptor (PgR) were determined using LBA methods in 15 tumors from 15 pregnant patients with breast cancer. In addition, immunohistochemistry was done for ER, PgR, pS2, heat shock protein 27 (hsp27), and HER-2/neu on 12 of the 15 tumors.

RESULTS

Five of 15 (33%) tumors were positive for ER by LBA, compared with 52% of tumors from age-matched nonpregnant patients. Six of 12 (50%) were ER-positive by immunohistochemistry. For PgR, 7 of 15 (47%) tumors were positive by LBA, compared with 42% of tumors from nonpregnant patients. Ten of 12 (83%) stained positive for PgR. By LBA, 67% of tumors studied were positive for ER or PgR or both, as opposed to 57% of tumors from the nonpregnant comparison group. Two other estrogen receptor-mediated proteins, pS2 and hsp27, were present by staining in 8 of 12 (67%) and 10 of 12 (83%) of tumors, respectively. Seven of 12 tumors (58%) had positive staining for HER-2/neu, whereas only 16% of age-matched nonpregnant patients had positive-staining tumors.

CONCLUSION

By LBA, the incidence of ER and PgR in breast tumors from pregnant women was not significantly different from that of tumors from nonpregnant age-matched patients. Some ER-negative tumors were PgR, pS2, or hsp27 positive, indicating that an intact estrogen response system was operative although ER was not detectable by standard LBA.

Heat shock protein hsp70 in patients with axillary lymph node-negative breast cancer: prognostic implications

BACKGROUND

Cell synthesis of heat shock (stress-response) proteins is increased by a variety of environmental and pathophysiological stressful conditions. The 70-kd heat shock protein (hsp70) is thought to be involved in protein-protein interactions including those of the protein products of the human c-myc oncogene and the p53 (also known as TP53) tumor suppressor gene.

PURPOSE

The purpose of this study was to investigate whether elevated hsp70 expression may be an indicator of biological stress experienced by a breast cancer and may, therefore, predict disease outcome.

METHODS

Levels of hsp70 were determined by Western blot analysis in primary breast tumors from patients with negative axillary lymph nodes. We performed exploratory data analyses on a set of 162 primary breast cancers and constructed prognostic indexes of hsp70 expression levels. The optimal cutpoint for hsp70 expression was considered to be the value yielding the greatest separation for disease-free survival for the resulting two groups of patients. That cutpoint was then validated in a set of 345 tumors by univariate and multivariate analyses. Data were analyzed for overall survival, disease-free survival, tumor size, and patient age, as well as estrogen receptor and progesterone receptor status, ploidy (DNA content), and percentage of cells in S phase as determined by flow cytometry.

RESULTS

Expression of hsp70 emerged as a useful prognostic factor, both in univariate and in multivariate analyses. Patients whose tumors had high expression of hsp70 had significantly shorter disease-free survival (P = .006). The other statistically significant factors were S-phase fraction (P = .008) and tumor size (P = .01). For patients who received adjuvant therapy, hsp70 was the only independent predictor of disease recurrence (P = .05). For those with tumors 1-3 cm in diameter, hsp70 (P = .008) and S-phase fraction (P = .02) were statistically significant predictors of recurrence.

CONCLUSIONS

Measurement of hsp70 expression in primary tumors from patients with node-negative breast cancer may be useful in identifying patients at high risk for disease recurrence and thus may affect decisions regarding treatment after surgery.

IMPLICATIONS

Future studies should be performed to determine if detection of hsp70 by immunohistochemistry can be used to predict clinical outcome and to better understand the relationships between hsp70 and the effects of various treatment modalities.

Measurement of steroid hormone receptors in breast cancer patients on tamoxifen

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

Expression of HER-2/neu oncoprotein in human breast cancer: a comparison of immunohistochemical and western blot techniques

Three hundred and one primary breast cancers from patients with tumor infiltrated lymph nodes were analyzed for the presence of HER-2/neu oncoprotein by two procedures: Western blot (WB) and immunohistochemistry (IHC). Overexpression of this protein was found by WB in 16.6% of the tumors, and by IHC in 16.3%. Concordance between the two methods was found in 95% of tumors (286/301). In 7 cases we found HER-2/neu by IHC but not by WB, while the opposite was found in the remaining 8 patients. This discrepancy was found mainly in samples with HER-2/neu values just above the cut points and were therefore close to the sensitivity limits of the procedures used here. This study helps to define the parameters that should be considered to evaluate the immunostaining for HER-2/neu as positive (i.e., membrane staining, IHC score of 2 or more). The results obtained by both techniques were correlated with several currently used prognostic factors. Higher HER-2/neu protein expression was found in tumors lacking estrogen or progesterone receptors, in tumors with high S-phase fraction and in patients with more than 3 positive lymph nodes. In contrast, no relationship was found between overexpression of this protein and tumor size, ploidy, or age of the patient. Patients with elevated HER-2/neu expression showed a significantly worse overall survival by both methods, IHC (p = 0.05) and WB (p = 0.001). In conclusion, there is very high agreement between IHC and WB when measuring expression of HER-2/neu and both techniques showed prognostic significance.

Response of human breast cancer cells to heat shock and chemotherapeutic drugs

Previous studies have shown that certain chemotherapeutic drugs are less effective on tumor cells when cells have been previously exposed to hyperthermia. In the present study, we have evaluated whether specific modifications in heat shock protein (hsp) expression are associated with resistance to anticancer drugs. RNA levels for hsp90, hsp70, and hsp27 were studied by Northern and slot blots, while proteins were studied by two-dimensional gel electrophoresis, in MCF-7/BK and MDA-MB-231 breast cancer cells. The sensitivities of these cells to doxorubicin, colchicine, 5-fluorouracil, cisplatin, actinomycin D, and methotrexate were tested by clonogenic assays. These techniques were applied to both cell lines before (control) and after heat shock. The study revealed that elevated hsp70 and hsp27 levels were associated with doxorubicin resistance. In addition, the presence of phosphorylated hsp27 isoforms was also associated with doxorubicin resistance. The study showed that elevated hsps were not associated with multidrug resistance. Heat shock did not induce P170 glycoprotein mRNA overexpression or resistance to the other drugs tested. We also found that the level of doxorubicin protection conferred by the overexpression of hsp was lower than that obtained in cells expressing a multidrug resistance phenotype (MDA-A1R cells). In these cells, heat shock did not confer additional doxorubicin resistance and hsp27 phosphorylation was deficient. Our studies suggest that specific hsps are associated with doxorubicin resistance in certain human breast cancer cells and that this mechanism seems to be independent of the multidrug resistance system.

Effect of human papillomavirus infection on estrogen receptor and heat shock protein hsp27 phenotype in human cervix and vagina

In this study we have explored whether, as a consequence of human papillomavirus (HPV) infection, there is inappropriate expression of estrogen receptor and/or of a small heat shock protein of 27,000 daltons (hsp27). Estrogen receptor, hsp27, and HPV structural antigens were detected by immunocytochemistry, while HPV DNA (6/11, 16/18, 31/35/51) was determined by in situ hybridization in cervical and vaginal samples from 40 patients. Most of the samples with HPV infection without atypia showed a shift in estrogen receptor expression since this protein appeared mainly in the intermediate and superficial cell layers. In the serial sections, these layers displayed strong estrogen receptor staining, together with high HPV replication and late HPV gene expression. In the samples with HPV infection and atypia, estrogen receptors were also frequently found in the basal and parabasal cells, but almost 20% of these samples did not show estrogen receptors. The presence of high estrogen receptor expression was not dependent on a particular HPV DNA type. On the other hand, interesting modifications in hsp27 expression were observed in the HPV-infected tissues. The cytoplasm of the cells with koilocytotic changes showed very low hsp27 content. In several samples this protein appeared in the nuclei of the superficial cells, and sometimes it was also observed in the cytoplasm of the basal cells. These changes in estrogen receptor and hsp27 expression suggest that these proteins might have a role in virus-host biology.

Tamoxifen and the isomers of 4-hydroxytamoxifen in tamoxifen-resistant tumors from breast cancer patients

PURPOSE

The antiestrogen tamoxifen is effective in therapy for breast cancer. However, its use is limited by the eventual development of acquired tamoxifen resistance in many patients. The mechanisms responsible for tamoxifen resistance remain unknown; loss of estrogen receptor (ER), selection of hormone-independent breast cancer clones, or alterations in serum tamoxifen levels after long-term use do not explain acquired resistance in most patients. Using an experimental model in which human breast cancer cells develop resistance in athymic mice treated with tamoxifen, we have recently shown that acquired resistance is associated with markedly reduced cellular concentrations of tamoxifen and by isomerization of the trans-4-hydroxy metabolite to the less potent cis isomer.

MATERIALS AND METHODS

Using a sensitive high-performance liquid chromatography (HPLC) assay, we have now measured levels of tamoxifen and its major metabolites in a series of 14 tumors from patients treated with tamoxifen. The duration of therapy ranged from 1 month to 6 years.

RESULTS

Tumor tamoxifen levels varied over a wide range. Low concentrations were observed in tumors from eight patients, all demonstrating progressive disease at the time of biopsy after a minimum duration of treatment of 6 months. Six tumors had moderate to high tamoxifen levels, two from patients responding to tamoxifen, one from a patient with stable disease, and three from patients with disease progression. Both the cis and trans isomers of the potent antiestrogenic metabolite 4-hydroxy-tamoxifen were detected in 11 tumors. Six tumors had high ratios of the cis to trans isomer (1.10:2.06), all from patients not responding to tamoxifen. The five tumors with low cis:trans ratios included the two tumors from responding patients and three from patients with progression. All but one of the 11 nonresponding patients had either a low tumor tamoxifen level, a high cis:trans ratio, or both.

CONCLUSION

This study clearly demonstrates a wide range of tumor tamoxifen levels and accumulation of the less antiestrogenic cis isomer of 4-hydroxytamoxifen in some patients on tamoxifen therapy. Additional study is necessary to determine if these metabolic profiles are related to the development of tamoxifen resistance.

Immunological evidence for the identity between the hsp27 estrogen-regulated heat shock protein and the p29 estrogen receptor-associated protein in breast and endometrial cancer

Previous studies have shown several similarities between an estrogen-regulated heat shock protein of 24,000-28,000 daltons (hsp27), and a cytoplasmic estrogen receptor-associated protein of 27,000-29,000 daltons (p29). These proteins have been studied by monoclonal antibodies generated in different laboratories. In the present report we have performed immunocytochemical and immunoblot studies to explore if the monoclonal antibodies against hsp27 (C11) and against p29 (ER-D5) may be identifying the same protein. Breast and endometrial carcinomas and normal endometrial samples were examined by immunocytochemistry (in mirror sections and by double-immunostaining). Identical hsp27 and p29 immunostaining intensity, distribution, and percentage of stained cells was demonstrated by immunocytochemistry. The antigens examined by the two antibodies appeared in the same cells. Cytosols from tumors analyzed by the Western blot technique revealed that the C11 and the ER-D5 antibodies recognized bands with identical electrophoretic mobility. Immunoprecipitation studies with one antibody, C11, followed by Western blot showed that the precipitate was reactive with both antibodies. Identical C11 and ER-D5 reacting spots were observed after blotting proteins separated by high resolution two-dimensional gel electrophoresis. In addition, p29 protein was induced by heat shock in the estrogen receptor negative MDA-MB-231 human breast tumor cell line. These results strongly suggest that the two proteins under investigation are identical.

Estrogen receptors, progesterone receptors and heat-shock 27-kD protein in liver biopsy specimens from patients with hepatitis B virus infection

It has been proposed that in the human liver, the estrogen receptor gene may become inappropriately expressed as a consequence of HBV integration, contributing to cell transformation. This study was undertaken to examine estrogen receptor status in patients with hepatitis B virus infection and to analyze the expression of progesterone receptor and of a heat-shock 27,000-D protein (hsp27), both of which are estrogen regulated in estrogen target tissues. Receptor proteins were detected in liver biopsy specimens by immunocytochemistry using antireceptor monoclonal antibodies; a monoclonal antibody was also used to detect hsp27. Estrogen receptor and progesterone receptor were mainly seen in the nuclei of hepatocytes. The presence of hepatitis B virus infection did not always result in elevated estrogen receptor expression, but in general the expression of this receptor protein was higher in hepatitis B virus-positive patients than in patients with the same pathological findings (hepatitis, cirrhosis, hepatocarcinoma) but without hepatitis B virus. This was more clearly seen in the patients with hepatitis. Although estrogen receptor expression was moderate to high in many samples, the expression of the two biochemical markers of estrogen action at postreceptor levels (progesterone receptor and hsp27) was low or absent in most of the liver tissues examined, suggesting that in the liver the interaction of estrogen-estrogen receptor-DNA has characteristics inherent to this tissue.

Colocalization of estrogen and progesterone receptors with an estrogen-regulated heat shock protein in paraffin sections of human breast and endometrial cancer tissue

We have studied by immunocytochemistry and monoclonal antibodies the presence and localization of estrogen receptors, progesterone receptors, and a 24-kD estrogen-regulated heat shock protein in biopsies from breast and endometrial cancer patients. Three different tissue processing protocols were used to colocalize the antigens in the same tissue sections: a) frozen sections, b) formalin fixation with routine paraffin embedding, and c) picric acid-formaldehyde (PAF) fixation with a rapid embedding in paraffin. Frozen sections showed good receptor staining but poor 24-kD protein immunoreactivity, while routine paraffin sections (with or without DNase pretreatment) were inadequate to reveal the nuclear receptor proteins at the same level seen in frozen sections. On the other hand, all three proteins could be detected satisfactorily in PAF-fixed paraffin-embedded tissue. Using this procedure we were able to visualize 24-kD protein and estrogen receptor or progesterone receptor in individual cells in paraffin sections. The study revealed that in all of the estrogen receptor positive breast and endometrial tumor samples, almost 90% of the cells expressing the cytoplasmic 24-kD protein contained estrogen receptor in the cell nucleus. In contrast, 24-kD immunoreactive cells did not express progesterone receptors in almost 40% of the progesterone receptor positive tumor samples.

Corticotropin-releasing hormone, luteinizing hormone-releasing hormone, growth hormone-releasing hormone, and somatostatin-like immunoreactivities in biopsies from breast cancer patients

The presence of immunoreactive adrenocorticotropin-releasing hormone (CRH), luteinizing hormone-releasing hormone (LHRH), growth hormone-releasing hormone (GHRH), and somatostatin has been investigated by immunohistochemistry in forty biopsies from breast cancer patients. All of these hypothalamic hormones were found in about 30% of the samples, seen in the cytoplasm or in the nuclei of the tumor cells. Positive immunostaining for the hypothalamic hormones was present in colloid, lobular, and infiltrating ductal carcinomas. There was not a clear relationship between occurrence of staining for the hypothalamic hormones and the histologic grade of tumors or the clinical stage of the disease. Immunoreactive LHRH was more frequently found in breast tumors with estrogen and progesterone receptors. On the other hand, preneoplastic breast lesions expressed mainly somatostatin, while immunoreactivity was absent in normal mammary tissue.

Analysis of a 24-kilodalton (KD) protein in the human uterine cervix during abnormal growth

The authors have previously studied the presence and distribution of a 24-kilodalton (KD) estrogen-regulated protein in the human normal cervix (Am J Obstet Gynecol 1986; 155:1090-1096). This protein has recently been identified as a heat-shock protein, and in order to continue its study the authors have now examined its expression in preneoplastic to neoplastic cervical samples. The study involved 53 patients, the presence of 24-KD protein together with keratin and carcinoembryonic antigen (CEA) was investigated by immunohistochemical analysis. Cytosol samples from 15 patients with squamous cervical carcinomas were also studied by the Western blot technique, and the presence of estrogen receptors was analyzed biochemically. The 24-KD protein was observed in cervical intraepithelial neoplasias (CIN), but it was not useful to identify the different degrees of CIN examined. The 24-KD protein, keratin, and CEA were predominantly expressed in well and moderately differentiated squamous carcinomas in the more differentiated areas, and the protein was also found in cervical adenocarcinomas. The presence of 24-KD protein did not correlate with that of estrogen receptors in squamous cervical carcinomas. The Western blot and the immunohistochemical studies revealed that the antibody to 24-KD protein does not cross-react with epitopes of CEA and keratins.

Study of estrogen receptor, progesterone receptor, and the estrogen-regulated Mr 24,000 protein in patients with carcinomas of the endometrium and cervix

The presence of an estrogen-regulated protein with 24,000 molecular weight has been studied in 47 patients with endometrial carcinomas and in 29 patients with cervical carcinomas in order to correlate its presence with that of estrogen receptors (ERs) and progesterone receptors (PgRs). In the cytosol tumor samples the Mr 24,000 protein was detected by the Western blot technique using a monoclonal antibody (C11), while the presence of ER and PgR was studied by the one-point dextran-coated charcoal assay. In the tumor tissue sections immunohistochemistry was applied to detect Mr 24,000 protein, ER, and PgR; in these cases monoclonal antireceptor antibodies (H222 and mPRI) were used to localize the receptor proteins. In endometrial and endocervical adenocarcinomas the presence of Mr 24,000 protein correlated significantly with that of ER (P less than or equal to 0.05) in the cytosol samples; when the evaluation was performed in the tumor sections, the presence of Mr 24,000 protein correlated with that of ER (P less than or equal to 0.005) and PgR (P less than or equal to 0.05) as well. The study also showed that almost 70% of the well-differentiated adenocarcinomas had ER, PgR, and Mr 24,000 protein. In 25% of the endometrial adenocarcinomas examined the tumors were associated with normal, proliferative, and hyperplastic endometrium; in these cases the presence of ER, PgR, and Mr 24,000 protein was evaluated by immunohistochemistry in the malignant and nonmalignant endometrium. On the other hand, there was a lack of correlation between Mr 24,000 protein, ER, and PgR in the squamous carcinomas of the uterine cervix and in the endometrial adenocarcinomas with squamous cells. In most of these cases the tumors lacked ER and PgR although 80% of them contained the Mr 24,000 protein to a variable degree. It is suggested that Mr 24,000 protein is involved in growth and differentiation (the Mr 24,000 protein is a heat shock protein) and that the gene coding of this protein is under hormonal control only in those tissues where growth and differentiation are strongly hormonally controlled (breast and endometrium).

Ultrastructural and immunoelectron-microscopic study of the human pharyngeal hypophysis

The ultrastructural characterization of seven cell types in the pharyngeal hypophysis from adult subjects is described. By immunoelectron microscopy, two of the granular cell types were identified as growth-hormone- and prolactin-producing cells. The vascular supply of this gland was mainly composed of capillaries without fenestrations. Review of the literature allows a comparison with the ultrastructure of the sellar adenohypophysis and with the pharyngeal hypophysis of children.

Intensification of the immunocytochemical reaction by staining both sides of tissue sections

We describe how the efficiency of immunostaining may be increased by staining paraffin sections on both sides. This modification exposes more antigenic binding sites per unit tissue area, as shown by the peroxidase-antiperoxidase and the avidin-biotin-peroxidase complex methods. Using antigen-rich tissue samples, the modified procedure made it possible to use more dilute primary antiserum or to reduce the incubation time of the tissue with the primary antibody. Alternatively, in tissue samples with sparse antigenic sites, the procedure made it possible to visualize and document very weak immunoreactivities.

Localization of an estrogen-responsive protein in the human cervix during menstrual cycle, pregnancy, and menopause and in abnormal cervical epithelia without atypia

The presence and distribution of an estrogen-responsive protein with a molecular weight of 28,000 were investigated in the human cervix with use of a monoclonal antibody. This biochemical marker protein was localized with a light microscope and by immunocytochemical studies of the different cell types and cell layers of the cervix. The study involved 60 patients, 48 of whom were sexually active, eight pregnant, and four in menopause; strips of endometrial tissue were analyzed in 22 patients. In cycling women the estrogen-responsive protein was identified in the subcolumnar cells of the endocervix, whereas in the ectocervix the protein was detected mainly in the parabasal and intermediate cell layers but alternating with unstained areas. There were no significant variations in the presence of the protein in the ectocervical and endocervical epithelium during the different phases of the menstrual cycle. During pregnancy a more intense and homogeneous immunostaining of the protein was seen in the ectocervix, endocervical areas with squamous metaplasia showed strong estrogen-responsive immunostaining, and predecidual and decidual cells were positive for the protein. There were no prominent changes in the presence and distribution of the protein in the abnormal ectocervical samples without atypia. However, in the endocervix the protein detection was useful to follow the evolution of the subcolumnar cells to simple squamous metaplasia. These samples displayed intense estrogen-responsive immunostaining. No immunoreaction was observed in the cervix of menopausal women. The results of the present study have shown that the response of the normal uterine cervix to estrogenic influence is heterogeneous in different cervical cell types and in different sites within the same cell layer; during the normal menstrual cycle the capability of response of the cervical cells to variations of estrogen levels is limited when compared with the endometrium; and during pregnancy and in the process of indirect squamous metaplasia some of the cervical cells seem to be very reactive to estrogenic stimulation. This study defines the normal baseline for further analysis of the estrogen-regulated protein in the uterine cervix during abnormal growth.