Primary chemotherapy in breast invasive carcinoma: predictive value of the immunohistochemical detection of hormonal receptors, p53, c-erbB-2, MiB1, pS2 and GST pi.

Primary chemotherapy in operable breast invasive carcinoma enables tumour reduction and conservative surgery. In order to search for one or more biological factors capable of predicting tumour behaviour under primary chemotherapy, and subsequent patient survival, an immunohistochemical study was performed with specific antibodies to p53, c-erbB-2 (Her-2/neu), Mib1 (antiKi-67), pS2, GST pi, oestrogen receptors (ERs) and progesterone receptors (PRs). Core biopsies, obtained before primary chemotherapy, were available from a series of 128 breast invasive carcinomas treated between January 1985 and April 1989, with a median follow-up of 93.3 months. Univariate statistical analysis showed that negative ER detection by immunohistochemistry (IHC) was highly correlated with chemosensitivity (P = 0.001). A high percentage of Mib1-positive tumour cells (> 40%), as well as initial tumour size less than 4 cm, were also correlated with tumour responsiveness to chemotherapy (P = 0.009 and P = 0.03). By multivariate analysis IHC-ER, Mib1 and initial tumour size were independent predictors, the last parameter being the most important. Concerning subsequent patient survival, c-erbB-2 overexpression, as detected by IHC, was significant with respect to overall survival (OS) (P = 0.0006), disease-free interval (DFI) (P = 0.03) and metastasis-free interval (MFI) (P = 0.008) by univariate analysis. Furthermore, c-erbB-2 was the major independent prognostic factor for OS and MFI by multivariate analysis.     

Estrogen receptor (ER) and progesterone receptor (PgR), by ligand-binding assay compared with ER, PgR and pS2, by immuno-histochemistry in predicting response to tamoxifen in metastatic breast cancer: a Southwest Oncology Group Study

Results of estrogen receptor (ER) and progesterone receptor (PgR) ligand-binding assays (LBAs) are strongly correlated with ER and PgR by immuno-histochemistry (IHC). To investigate whether ER and PgR by IHC are also strongly correlated with tamoxifen response, time to treatment failure (TTF) and overall survival (OS), the results of the 2 methods were directly compared in 205 patients with ER(+) metastatic breast cancer treated with daily tamoxifen (Southwest Oncology Group protocol 8228) with 9 years median follow-up. pS2, another estrogen-regulated molecule, was also analyzed. Tumors were scored for IHC from 0 to 5, according to the proportion of positively stained cells. These IHC scores for both ER and PgR were significantly associated with LBA levels (p < 0.001). There was a significant direct relationship between higher IHC ER, PgR and pS2 and increasing response to tamoxifen. TTF and OS were also significantly longer for patients with higher ER or PgR, but not pS2, IHC scores. Low, intermediate and high ER or PgR categories showed similar differences in response rates whether defined by LBA or IHC. In logistic regression models which included ER, PgR and pS2 by IHC; ER and PgR by LBA; and menopausal status, only ER (IHC) and pS2 (IHC) retained significance for predicting tamoxifen response (p = 0. 02 and p = 0.005, respectively), along with menopausal status (for PgR by IHC, p = 0.09). Increasing ER and PgR by IHC, as by LBA, are thus significantly associated with a progressively better response and longer survival in ER(+) metastatic breast cancer. pS2 is also predictive in this setting.     

Pathological features of breast cancer response following neoadjuvant treatment with either letrozole or tamoxifen

Morphological characteristics, grading features, proliferation marker MIB1, apoptosis (by Tdt-mediated duTP-biotin nick-end labelling (TUNEL)), Bcl-2 expression, oestrogen receptor (ER) and progesterone receptor (PgR) status were compared in ER-positive breast cancers before and after 3 months of neoadjuvant therapy with either letrozole or tamoxifen. Daily treatment was with letrozole 2.5 mg (12 patients) or 10 mg (12 patients), or with tamoxifen 20 mg(24 patients). Letrozole treatment was associated with a pathological response in 17 of 24 (71%) patients. The predominant change in grading features was a decrease in mitosis, and the expression of MIB1 was reduced in all of the 22 evaluable cases. Whilst only marginal changes were observed in ER expression following letrozole therapy, PgR reactivity was reduced in 20 of 21 evaluable cases which were initially PgR-positive, becoming undetectable in 16 patients. Tamoxifen treatment was associated with pathological response in 15 of 24 (63%) tumours. In contrast to letrozole, the dominant change in grading feature was an increase in tubule formation, ER score was markedly reduced in most cases, and the most common effect on PgR was an increased expression. Following treatment with either tamoxifen or letrozole, variable effects were observed on the apoptotic index and expression of Bcl-2. These results indicate that both letrozole and tamoxifen have marked influences on the pathological features of breast cancer during neoadjuvant therapy. However, the effects of the two agents varied such that the phenotypes of letrozole- and tamoxifen-treated tumours differ markedly. Effects on clinical, pathological and biological endpoints were frequently disconcordant--future studies will therefore require the evaluation of multiple parameters in order to fully assess tumour response.     

Response to mitoxantrone in advanced breast cancer: correlation with expression of c-erbB-2 protein and glutathione S-transferases.

Sixty-eight patients with advanced breast cancer were treated with mitoxantrone and clinical responses assessed. Expression of c-erbB-2 protein and cytosolic glutathione S-transferase (GST) isoenzymes pi, alpha and mu by the primary tumours of these patients was determined immunohistochemically, and correlated with treatment response. Tumours overexpressing c-erbB-2 (n = 16, 23%) showed a lower response rate (50% vs 58%) and shorter duration of response to treatment, compared with c-erbB-2 negative tumours. These associations were not statistically significant but survival following start of treatment was significantly shorter in the c-erbB-2 positive group. For each GST isoenzyme, the response rate and duration of response of the group showing enzyme expression did not differ significantly from those with negatively staining tumours. These data do not support a role for expression of GSTs alone in resistance to mitoxantrone monotherapy in advanced breast cancer. The poorer post treatment survival of patients with c-erbB-2 positive tumours suggests they could be selected for more intensive treatment regimens.     

Relationship between c-erbB-2 protein product expression and response to endocrine therapy in advanced breast cancer.

Of 221 patients with breast cancer of known epidermal growth factor receptor (EGFR) and oestrogen receptor (ER) status, 99 had developed recurrences during the period of follow-up (range 3-60 months, median 24 months). Of these, 72 received endocrine therapy as first-line treatment for relapse. Immunohistochemical assessment of c-erbB-2 protein product expression was made using paraffin-embedded tumour tissue from 65 of these 72 patients. Including patients whose disease remained stable for more than 6 months with those showing an objective response (CR or PR for more than 3 months), only one (7%) of 14 c-erbB-2 positive tumours responded to endocrine manipulation compared with 19 (37%) of 51 c-erbB-2 negative tumours (P less than 0.05). Coexpression of c-erbB-2 reduced the response rate of ER positive patients from 48% to 20% and of ER negative cases from 27% to 0% (P less than 0.01). EGFR and c-erbB-2 protein appeared to have additive effects in reducing the likelihood of response, and none of eight patients with EGFR positive, c-erbB-2 positive tumours derived benefit from endocrine therapy. The results of this study suggest that c-erbB-2 protein overexpression, a marker of poor prognosis in breast cancer, is associated with a lack of response to endocrine therapy on relapse, and particularly in combination with EGFR may be useful in directing therapeutic choices.     

Immunoradiometric detection of pS2 and total cathepsin D in primary breast cancer biopsies: their correlation with steroid receptors.

Commercially available immunoradiometric assays were used for pS2 and total cathepsin D determination in the cytosol fraction obtained from 266 primary breast cancers. We show that pS2 and cathepsin D values were significantly associated (Spearman''s rank correlation: P < 0.0001) in tumours from lymph node-positive patients (N+), while such association did not reach significance in tumours taken from patients with negative lymph nodes (N-). Moreover, cathepsin D concentrations in pS2-rich tumours (pS2 above the median value, 5 ng mg-1 protein) were significantly higher (Mann-Whitney-Wilcoxon''s rank-sum test: P = 0.00001) than those obtained in the samples expressing less than 5 ng of pS2 per mg of protein. pS2 was also correlated to both the oestrogen receptor (ER) (Spearman''s rank correlation: P < 0.0001) and the progesterone receptor (PR) (Spearman''s rank correlation: P = 0.022). No significant differences in the expression of pS2 and cathepsin D taken from N+ and N- patients were found. Furthermore, no significant differences in pS2 and cathepsin D expression were obtained by stratifying tumours on the basis of their size (T). pS2 and cathepsin D values obtained in ER-positive/PR-positive tumours did not significantly differ from the values obtained in ER-positive/PR-negative and in ER-negative/PR-positive tumours. We conclude that pS2 could have a role in cathepsin D expression, and that it can be used in the assessment of a functioning oestrogen response machinery in those tumours that express only ER.     

Immunoradiometric measurement of pS2 in breast cancer--correlation with steroid receptors and plasminogen activators.

pS2 was measured by radioimmunometric assay in tumour extracts from 197 breast cancer patients. Values ranged from 0 to 50 ng/mg protein (mean 9.6 and median 3 ng/mg). We found no correlation with age, menopausal status, nodal metastases, disease stage or tumour histology. There was, however, a linear relationship with both ER (p < 0.0001) (particularly nuclear ER) and PR (p < 0.0001) expression determined by enzyme immunoassay (ELISA), as well as a good correlation when high and low expressors were stratified on the basis of combined ER/PR expression using consensus cut-off points. Only 15% of ER - ve/PR - ve patients were classified as pS2 + ve compared with 83% of those who were ER + ve/PR + ve. pS2 was also directly correlated with high expression of tPA and inversely with uPA. Comparison with previous studies showed that the current ELISA method produced consistent results, in contrast to other methods, particularly those based on immunohistochemical detection. The close relationship between pS2 and both steroid receptors suggests that pS2 may be important in terms of defining hormone-responsive patients who are likely to benefit from endocrine therapy.     

雌激素诱导蛋白pS2表达与ER阳性原发乳腺癌患者辅助内分泌治疗疗效的关系

目的:探讨雌激素诱导蛋白pS2的表达与乳腺癌临床参数和辅助三苯氧胺TAM治疗疗效的关系,明确pS2对辅助内分泌治疗的指导地位。方法:采用免疫组化S蛳P法检测81例ER阳性原发乳腺癌的石蜡切片pS2的表达, 统计学分析其与预后的关系。结果:原发乳腺癌pS2的阳性表达率为66.7 %,其表达与手术年龄(P=0.037)、月经状态(P=0.016)、肿瘤大小(P=0.029)、PR表达情况(P<0.001)密切相关,年龄小于50岁、绝经前、小肿瘤、PR阳性的患者pS2阳性率高。单因素分析和多因素分析均表明pS2是预测OS的独立预后因子。同时pS2对DFS也具有独立预后价值(P=0.023)。结论:pS2是预测ER阳性乳腺癌患者辅助内分泌治疗疗效的独立指标。     

Measuring IGF-1, ER-α and EGFR expression can predict tamoxifen-resistance in ER-positive breast cancer

In vitro studies have suggested that tamoxifen resistance may be due to altered expression and downstream signalling of insulin-like growth factor-1 (IGF-1) receptor (IGF-1l), oestrogen receptor-alpha (ERα), epidermal growth factor receptor (EGFR) and HER-2. We investigated which gene expressions could predict tamoxifen resistant breast cancer. Expression of IGF-1R, IGF-1 ligand (IGF-1), ERα, EGFR and HER-2 in 91 ER-positive breast cancer tumours were measured using real-time PCR and correlated with clinical outcome. The tamoxifen resistant group (n=20) consisted of: i) tumours which were resistant to neoadjuvant tamoxifen treatment and ii) tumours which were excised from patients who later developed recurrence or metastasis during adjuvant tamoxifen treatment. These were compared with tamoxifen sensitive tumours which were surgical excision specimens from patients who did not develop recurrence/metastasis during adjuvant tamoxifen treatment. Tumours with higher IGF-1 ligand and ERα expression took longer to develop tamoxifen resistance. Tamoxifen resistant tumours had lower IGF-1 and ERα expression compared to tamoxifen-sensitive tumours. IGF-1 expression strongly correlated with ERα expression in the tamoxifen sensitive group only. ERα inversely correlated with EGFR expression in the tamoxifen resistant group only. We conclude that IGF-1 ligand and ERα expression in breast carcinomas can be measured to predict tamoxifen resistance. Measuring ERα expression using RT-PCR may be more sensitive than immunohistochemistry in determining anti-oestrogen sensitivity.     

Extranuclear expression of hormone receptors in primary breast cancer.

BACKGROUND: Hormone receptor (HR)-positive breast cancer cells grow through estrogen receptor (ER)-signaling pathways that mediate both genomic and nongenomic actions, which cross-talk with growth factors associated with resistance to tamoxifen. The aim of this study was to explore the cross-talk between extranuclear expression of ER and progesterone receptor (PR) and growth factor signaling pathways in primary breast cancer. PATIENTS AND METHODS: The extranuclear expression of ER and PR was examined in 219 primary breast cancers by immunohistochemical staining. Specimens showing such expression were further examined for the expression of pAkt and aromatase. Staining reactions were scored on the basis of intensity and distribution in the tumors. RESULTS: Extranuclear expression of ER or PR was observed in 21 cases (9.5%), which included four cases for ER and 20 cases for PR. Among these patients, HER-2, pAkt, and aromatase-positivity were observed in 14 cases (66.6%), 13 cases (61.9%), and 14 cases (66.6%), respectively. On the basis of nuclear HR expression, 11 of these cases were categorized as ER-positive/PR-negative, while two were ER-negative/PR-positive. Of these 13 cases, increased pAkt staining was found in 11 cases (84.6%). In particular, among the 11 ER-positive/PR-negative cases, elevated pAkt and aromatase were found in 10 (90.9%; P<0.01) and nine cases (81.8%), respectively. CONCLUSIONS: PR is expressed extranuclearly more frequently than ER in primary breast cancer, and extranuclear HRs cross-talk with the Akt/HER-2-signaling pathways and activation of aromatase. These observations may explain the more beneficial effects of aromatase inhibitors than tamoxifen for ER-positive/PR-negative patients.     

Age interacts with the expression of steroid and HER-2 receptors in operable invasive breast cancer

BACKGROUND: The negative association between the oestrogen receptor (ER) and the human epidermal growth factor receptor 2 (HER-2) in breast cancer travels in both directions. ER+ tumours are less likely HER-2+ and HER-2+ tumours are less likely ER+. METHODS: We studied the age-related immunohistochemical (IHC) expression of ER, progesterone receptor (PR) and HER-2 in 2,227 tumours using age as a continuous variable. Steroid receptors were considered positive for any nuclear staining of invasive cancer cells and for HER-2, either for strong expression by IHC (score 3+) or gene amplification by fluorescence in situ hybridisation (FISH). Based on nonparametric regression, the age-related association between steroid receptors and HER-2 was presented as likelihood curves. RESULTS: The association between ER or PR and HER-2 is age-related. The age-related expression of ER and PR is HER-2 dependent. In HER-2(-) cases, the odds ratio (OR) for being ER+ was 2.594 (95% CI = 1.874-3.591) up to age 50 and age-independent thereafter; for PR-expression the OR was 2.687 (95% CI = 1.780-4.057) up to age 45 and 0.847 (95% CI = 0.761-0.942) thereafter. In HER-2+ cases, the OR was 0.806 (95% CI = 0.656-0.991) to be ER+ and 0.722 (95% CI = 0.589-0.886) to be PR+. The age-related OR for breast cancers to be HER-2+ is steroid receptor dependent. Taking together, ER+PR+HER-2+ breast cancers appear on average 5.4 years earlier than breast cancers of any other ER/PR/HER-2 phenotype (95% CI = 3.3-7.5; P < 0.0001). CONCLUSION: There is a qualitative interaction between age and expression of steroid and HER-2 receptors. Our findings suggest a strong age-related selective growth advantage for breast tumour cells belonging to the ER+PR+HER-2+ subgroup.     

Automated and quantitative immunocytochemical assays of Bcl-2 protein in breast carcinomas.

Expression of the bcl-2 gene was investigated in 218 human breast carcinomas by immunohistochemical analysis. Immunodetections were assessed using (1) frozen sections, (2) documented commercially available monoclonal antibody (bcl-2/124, Dako), (3) automation of immunoperoxidase technique (Ventana) and (4) quantitative evaluation of results by image analysis (SAMBA) and statistical analysis of quantitative data (BMDP software). Bcl-2 protein expression was correlated with current prognostic indicators and with molecular markers detected by the same procedure as for Bcl-2. It was shown that Bcl-2 expression is not related to patients'' age, tumour size and type or lymph node status, but an inverse relationship was observed between Bcl-2 and tumour grade (P < 0.0001). An inverse relationship was also observed between Bcl-2 expression and p53 (P < 0.0001), Ki67/MIB1 antigen- (P = 0.0012), and P-gp- (P = 0.002) positive immunoreactions. In contrast, anti-Bcl-2 positive reaction was significantly associated with ER-positive (P < 0.001) and with ER/PR-positive or ER/PR/pS2-positive immunoreactions (P < or = 0.005). Bcl-2 expression was independent of CD31 and cathepsin D expression. Thus, Bcl-2 protein, thought to be antiapoptotic, exhibits parodoxical expression in human breast carcinomas. It is strongly detected in low-grade tumours (well-differentiated) with low (MIB1) growth fraction, but is independent of the tumour progression (size, node status, CD31, and cathepsin D). Bcl-2 acting on apoptosis is related to p53 gene abnormalities in breast carcinomas. Bcl-2 protein expression may also be involved in response to endocrine therapy (associated to ER/PR/pS2 positive immunoreactions) and probably with chemoresistance mechanisms (inverse relationship with P-gp).     

激素受体和HER-2及Ki-67预NSL腺癌新辅助化疗疗效价值的分析

目的：探讨乳腺癌组织中雌激素受体（ER）、孕激素受体（PR）、人表皮生长因子受体2（HER-2）及Ki-67的表达状态对新辅助化疗反应的预测作用以及化疗前后其表达差异对疗效的影响。方法：免疫组织化学方法检测新辅助化疗前后118例乳腺癌组织的ER、PR、HER-2及Ki-67的表达情况,并分析其与新辅助化疗疗效的关系。结果：118例新辅助化疗乳腺癌病例中,ER-和PR-组pCR分别为26．1％和27．1％,明显高于ER＋组11．1％和PR＋组6．8％,P-0．003。HER-2和Ki-67的表达对新辅助化疗疗效无显著影响。新辅助化疗前ER、PR与Ki-67的表达呈明显负相关,P〈0．001;新辅助化疗后Ki-67的高表达病例数显著减少,P-0．001。结论：ER-／PR-的患者对新辅助化疗更为敏感,Ki-67在化疗后发生了显著下调,提示新辅助化疗能降低肿瘤的增殖活性。ER、PR及Ki-67可以作为新辅助化疗疗效的预测指标。     

Variation of hormonal receptor, pS2, c-erbB-2 and GSTpi contents in breast carcinomas under tamoxifen: a study of 74 cases.

Seventy-four post menopausal patients with primary non-metastatic invasive ductal carcinomas of the breast were first treated with tamoxifen alone (30 mg p.o. daily) for 5 months. To study changes induced by tamoxifen, core biopsies before treatment and surgical specimens after hormonal therapy were assayed by immunohistochemistry for oestrogen (ER) and progesterone receptors (PR), pS2, GSTpi and c-erbB2. After tamoxifen, ER and PR significantly decreased in 60 and 44 cases respectively, whereas 11 and 19 cases showed no variation and 2 and 11 cases showed an increase (P<10(-4)). GSTpi and pS2 showed a significant increase in 43 and 41 cases, a decrease in 2 and 21 cases and no variation in 29 and 12 cases (P<10(-4) and P=0.04 respectively). c-erbB-2 showed no significant variation under tamoxifen, increased in only three cases and decreased in 13 cases. No relation was found between these variations and efficiency of hormone therapy. Our results allow a better knowledge of protein expression modifications occurring in breast cancer cells under tamoxifen therapy. They are also more consistent with clone selection rather than with phenotype modification.     

Assesssment of the effect of pretreatment with neoadjuvant therapy on primary breast cancer.

Patients with invasive cancer of the breast (T1-4, N0-2, M0) were assigned to pretreatment based on oestrogen receptor (ER) status; patients with ER-negative tumours received chemotherapy [mitozantrone, methotrexate and mitomycin C (MMM)] for 3 months, patients with ER-positive tumours underwent endocrine therapy [luteinising hormone releasing hormone (LHRH) agonist goserelin (leuprolide-premenopausal) or 4-hydroxyandrostenedione (formestane-post-menopausal)] for 3 months. Of the first 100 patients assessed at 3 months, 47 with ER-positive tumours had a 40.4% response (premenopausal 53.8%; post-menopausal 35%) and 53 with ER-negative tumours had a 60% response (premenopausal 57%; post-menopausal 63%). Patients with early breast cancer (T1/T2) had a complete clinical resolution in 41% (16/39) of cases after MMM and in 20% (7/35) of cases following endocrine therapy compared with 14% (2/14) advanced tumours (T3/T4) following MMM and (0/12) following endocrine therapy. However, in those patients achieving a complete clinical response, subsequent appropriate surgery showed that 16 of 19 patients (84%) had evidence of residual viable tumour on histological examination.     

C-erbB-2 Onco-Protein Expression in Breast Cancer: Relationship to Tumour Characterisitcs and Short-Term Survival in Universiti Kebansaan Malaysia Medical Centre

Breast cancer is the commonest cancer affecting females in Malaysia, contributing 31% of all newly diagnosedcases amongst Malaysian women. The present retrospective cohort study evaluated the relationship between cerbB-2 onco-protein overexpression with various tumour characteristics and survival rate of breast cancerpatients treated at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between 1996-2000. CerbB-2 oncoprotein overexpression was determined by immunohistochemistry (IHC) and tumors showing 2+positivity were verified by Fluorescence In Situ Hybridization (FISH). One hundred and seventy two patientswere eligible for the study with a short-term follow-up (median) of 5.1 years. C-erbB-2 oncoprotein overexpressioncorrelated with lymph node positivity, oestrogen receptor (ER) and progesterone receptor (PR) negativity.Univariate analyses showed shorter disease free survival (DFS) and overall survival (OS) in patients with cerbB-2 oncoprotein overexpression, Malay ethnicity, higher tumour grade, lymph node positivity, ER and PRnegativity. In a subgroup of patients with c-erbB-2 oncoprotein overexpression, a shorter OS was observed inthose with lymph node positivity, ER and PR negativity. In multivariate prognostic analysis, lymph node status,ER status and tumour grading were the strongest independent prognostic factors for both OS and DFS. However,c-erbB-2 status was not a significantly independent prognostic factor, even in subsets with lymph node positiveor negative group. C-erbB-2 oncoprotein overexpression correlated well with lymph node status, ER and PR.Shorter OS and DFS were significantly observed in patients with c-erbB-2 oncoprotein overexpression. Lymphnode status, ER status and tumour grading were the only three independent prognostic factors for OS and DFSin this study. Although c-erbB-2 expression is obviously important from a biological standpoint, multivariateanalysis showed that it is not an independent prognostic indicator in breast carcinoma in the local population.     

The prognostic biomarkers HOXB13, IL17BR, and CHDH are regulated by estrogen in breast cancer.

PURPOSE: We previously identified three genes, HOXB13, IL17BR, and CHDH, that strongly predict clinical outcome in estrogen receptor (ER)-positive breast cancer patients receiving tamoxifen monotherapy. The biological mechanisms linking these genes to estrogen signaling and tamoxifen response in breast cancer remain to be determined. EXPERIMENTAL DESIGN: In a consecutive series of 148 ER-positive and ER-negative breast cancers, HOXB13, IL17BR, and CHDH gene expression was measured by quantitative real-time PCR and correlated with ER, PR, and HER2 expression. The role of estrogen and ER in the regulation of these three genes was assessed in several ER-positive and ER-negative breast cancer cell lines. RESULTS: In primary breast tumors, HOXB13 expression correlated negatively, and IL17BR and CHDH expression correlated positively, with ER status, and all three genes exhibited an ER-dependent correlation pattern with HER2 status that differs from PR and PS2, two canonical estrogen-regulated genes. Results using breast cancer cell lines show that these genes are regulated by estradiol in an ER-dependent manner, and that this regulation is abrogated by tamoxifen. CONCLUSIONS: HOXB13, IL17BR, and CHDH are estrogen-regulated genes, but their pattern of correlation with known positive (ER, PR) and negative (HER2) predictors of tamoxifen response differs from canonical ER signature genes. These results provide a biological rationale for the prognostic utility of these three genes in early-stage ER-positive breast cancer and for their potential to predict anti-estrogen resistance.     

HER-2/neu and p53 expression versus tamoxifen resistance in estrogen receptor-positive, node-positive breast cancer.

PURPOSE: An association between the overexpression of proto-oncogene HER-2/neu and resistance to tamoxifen in estrogen receptor (ER)-positive primary and metastatic breast cancer has been suggested. We examine a possible interaction between HER-2/neu or p53 expression and tamoxifen effectiveness in patients with ER-positive, node-positive disease treated with cyclophosphamide, doxorubicin, and fluorouracil in a large adjuvant chemotherapy trial (Cancer and Leukemia Group B [CALGB] 8541). Tamoxifen assignment was not randomized-physician discretion was used for premenopausal and postmenopausal women. Trial protocol then specified assignment to postmenopausal women with ER-positive tumors, although not all took tamoxifen. PATIENTS AND METHODS: CALGB 8541 assessed HER-2/neu expression in patients with ER-positive disease by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) and amplification by differential polymerase chain reaction (PCR). IHC assessed expression of p53. Univariate and multivariate proportional hazards models assessed tamoxifen-HER-2/neu status interactions and tamoxifen-p53 status interactions. RESULTS: HER-2/neu status was available for 651 patients with ER-positive disease; 650, 608, and 353 patients were assessed by IHC, PCR, and FISH, respectively. Approximately one half received tamoxifen. Reduction in risk of disease recurrence or death resulting from tamoxifen was approximately 37% (32% with overexpression and 39% with normal expression of HER-2/neu; n = 155 by IHC). The tamoxifen-HER-2/neu status interaction was not significant in multivariate analysis of all three HER-2/neu assessment methods. Tamoxifen-p53 interaction did not significantly predict outcome. CONCLUSION: Disease-free and overall survival benefit of tamoxifen in patients with ER-positive, node-positive breast cancer does not depend on HER-2/neu or p53 status. Our data suggest that neither HER-2/neu nor p53 expression should be used to determine assignment of tamoxifen.     

Response to endocrine manipulation and oestrogen receptor concentration in large operable primary breast cancer

Forty-three patients with large (greater than or equal to 4 cm) but operable carcinoma of the breast have been treated by endocrine manipulation before definitive local surgery. This has allowed the study of the relationship between response to therapy and pretreatment oestrogen receptor (ER) concentration, as measured by a dextran-coated charcoal adsorption method. Premenopausal patients (17) were treated by surgical (4) or medical (13) oophorectomy. Post-menopausal patients (26) received either tamoxifen (10) or an aromatase inhibitor (16). Response was assessed from statistical analysis of the changes in tumour size. On completion of 12 weeks of endocrine therapy, there was significant regression of tumour size in 18 of the 43 patients. All 18 patients had tumours with ER concentrations of greater than or equal to 20 fmol mg-1 cytosol protein. Conversely all patients except one progressing on treatment had tumours with ER concentrations of less than 20 fmol mg-1 cytosol protein. This relationship applied for both premenopausal and post-menopausal patients. The overall response rate of patients with tumours of ER concentration greater than or equal to 20 fmol mg-1 cytosol protein was 60%.