A randomised trial of primary tamoxifen versus mastectomy plus adjuvant tamoxifen in fit elderly women with invasive breast carcinoma of high oestrogen receptor content: long-term results at 20 years of follow-up.

BACKGROUND: Long-term analysis of a randomised trial in Nottingham comparing tamoxifen versus surgery as initial treatment demonstrated that in oestrogen receptor (ER)-unselected cases, surgery achieved better local control, with no difference in overall survival. It was suggested that for patients with ER-rich tumours, local control and survival may be comparable. We now present long-term follow-up of a randomised trial designed to address this clinical scenario. PATIENTS AND METHODS: One hundred and fifty three fit elderly (≥70 years) women with clinically node-negative primary invasive breast carcinoma <5 cm of high ER content [histochemical (H) score ≥100] were randomised 2:1 to primary tamoxifen (Tam) (N = 100) or mastectomy with adjuvant tamoxifen (Mx + Tam) (N = 53). RESULTS: With median follow-up of 78 months, there was no statistically significant difference in 10-year rates of regional recurrence (9.0% versus 7.5%), metastasis (8.0% versus 13.2%), breast cancer-specific survival (89.0% versus 86.8%) or overall survival (64.0% versus 66.0%) between Tam and Mx + Tam; however, local control was inferior with Tam (local failure rates 43.0% versus 1.9%; P < 0.001). CONCLUSION: Irrespective of the degree of ER positivity, surgery achieved better local control. However, there was excellent and similar survival in both groups. Tam could be considered in those who are 'frail', refuse or prefer not to initially undergo surgery.

Incidence of intramammary nodes in completion mastectomy specimens after axillary node sampling: implications for breast conserving surgery.

BACKGROUND: Axillary node sampling (ANS) is widely used in conjunction with breast conserving surgery in the treatment of primary breast cancers in the UK. Some evidence suggests that axillary staging techniques can miss intramammary nodes contained within the axillary tail of the breast. This study aims to assess the incidence of such nodes in completion mastectomy specimens in women who have had previous breast conserving surgery and ANS. METHODS: One hundred and fifty-seven completion mastectomy specimens were obtained from women who had previous breast conserving surgery and ANS, at the Nottingham Breast Institute over a 3-year period. The pathology samples underwent detailed histological examination to identify lymph nodes, and determine their disease status. RESULTS: Seventy-six (48%) of completion mastectomy specimens contained intramammary lymph nodes. Fifteen patients were upstaged (lymph node stage) because of the histological findings at completion mastectomy. One patient from the study population received additional systemic treatment, as a result of the upstaging. CONCLUSION: The incidence of intramammary nodes in this series correlates with previous data. This study shows that in breast cancer patients who undergo ANS, intramammary nodes, if present and more so positive, are unlikely to change systemic treatment decisions, but may increase the number of patients needing radiotherapy and or further axillary dissection.

Reading the prognosis of the individual with breast cancer.

AIM: To obtain better survival estimates for the individual than is provided by placement in an NPI group. METHOD: Consecutive primary operable breast cancers treated at Nottingham City Hospital 1990-1999. Ten year % actuarial survivals plotted for 10 ranges of NPI from 2.0 to 6.9. There is an excellent inverse correlation between median NPI value for each range and survival at 10 years. To enable estimation of survival for all individual values of NPI, a curve fitting technique applied to these results (by G.B.) gave the formula to estimate survival from the individual's NPI score: 10 year % survival for the individual=-3.0079 x NPI(2)+12.30 x NPI+83.84. This gave an r(2) of 0.98. RESULTS AND CONCLUSION: Greater accuracy in individual survival prediction is obtained by dividing women into 10 groups by NPI scores than in the originally described six groups; rank order of survival in relation to NPI score is preserved. A curve fitting technique has been applied to these data to give a formula for the prediction of 10 year survival for every 0.1 value of NPI.

Survival of invasive breast cancer according to the Nottingham Prognostic Index in cases diagnosed in 1990-1999.

UNLABELLED: The Nottingham Prognostic Index (NPI) is a well established and widely used method of predicting survival of operable primary breast cancer. AIMS: Primary: To present the updated survival figures for each NPI Group. Secondary: From the observations to suggest reasons for the reported fall in mortality from breast cancer. METHODS: The NPI is compiled from grade, size and lymph node status of the primary tumour. Consecutive cases diagnosed and treated at Nottingham City Hospital in 1980-1986 (n=892) and 1990-1999 (n=2,238) are compared. Changes in protocols towards earlier diagnosis and better case management were made in the late 1980s between the two data sets. RESULTS: Case survival (Breast Cancer Specific) at 10 years has improved overall from 55% to 77%. Within all Prognostic groups there are high relative and absolute risk reductions. The distribution of cases to Prognostic groups shows only a small increase in the numbers in better groups. CONCLUSION: The updated survival figures overall and for each Prognostic group for the NPI are presented.

Guidelines on the standards for the training of specialised health professionals dealing with breast cancer.

According to EUSOMA position paper 'The requirements of a specialist breast unit', each breast unit should have a core team made up of health professionals who have undergone specialist training in breast cancer. In this paper, on behalf of EUSOMA, authors have identified the standards of training in breast cancer, to harmonise and foster breast care training in Europe. The aim of this paper is to contribute to the increase in the level of care in a breast unit, as the input of qualified health professionals increases the quality of breast cancer patient care.

EUSOMA accreditation of breast units.

EUSOMA (European Society of Mastology) is the organisation representing Breast Cancer Specialists in all disciplines, covering all aspects of breast cancer from risk and prevention, through diagnosis and treatment of the primary tumour, follow-up, treatment of recurrent and advanced disease, pathology, reconstruction, psychology and audit. EUSOMA Guidelines have been published on several aspects of breast cancer and are on service provision as well as giving clinical guidance and providing the basis for audit.

Prognostic value of lymphovascular invasion in women with lymph node negative invasive breast carcinoma.

This study aimed to test the hypothesis that lymphovascular invasion adds prognostic information to histological grade and tumour size in node-negative invasive carcinoma of the breast. Lymphovascular invasion was assessed in haematoxylin and eosin tumour sections from 2760 patients with node-negative invasive breast carcinoma treated with definitive surgery. Patients were divided into two groups: 990 in the no adjuvant therapy series (diagnosed in 1974-1988) with median follow-up of 13 years; and 1765 in the selective adjuvant therapy series (1988-2000) with median follow-up of 6.8 years. Lymphovascular invasion was identified in 19% of tumours and was associated with larger tumour size, higher histological grade and younger age. Overall, survival was associated on multivariate analysis with lymphovascular invasion, histological grade and tumour size in both patient series, and with histological type in the no adjuvant therapy series. In conclusion, lymphovascular invasion is an independent prognostic factor in node-negative breast cancer and should be considered in decisions about adjuvant treatment in this group of women.

High levels of allele loss at the FHIT and ATM genes in non-comedo ductal carcinoma in situ and grade I tubular invasive breast cancers.

Fifty-four grade 1 tubular breast cancers and nine non-comedo ductal carcinoma in situ samples have been analyzed for loss of heterozygosity using a series of microsatellite markers. Markers mapping to regions of the genome for which loss of heterozygosity has been documented previously in higher-grade breast cancers were selected for this analysis. Even within this group of good prognostic early breast cancers, genetic events are very common. The highest levels of loss were observed for D3S1300, which maps within an intron of the recently identified FHIT gene. High levels of loss were also observed within the ATM gene. These findings indicate that allele loss at FHIT and ATM may be an important early event in the development of sporadic breast cancer.

Estrogen receptor assay in primary breast cancer and early recurrence of the disease.

Estrogen receptor assays of primary breast tumors have been related to early recurrence of the disease. A significantly longer disease-free interval was found in women whose primary tumor was estrogen receptor positive. Although there was no relationship of receptor content to stage of disease at mastectomy, the greatest difference between recurrence rates was found when the tumor had spread to the lymph nodes, especially to those in the apex of the axilla or in the internal mammary chain. Presence of estrogen receptor is closely related to histologically well-differentiated tumors, but it was found that poorly differentiated estrogen receptor-negative tumors recurred earlier than poorly differentiated receptor-positive tumors and had a very unfavorable prognosis.

Immunocytochemical localization of estrogen receptor in human breast tissue.

An immunocytochemical assay for the measurement of estrogen receptor (ER-ICA; Abbott Diagnostics) has been evaluated in 163 human breast carcinomas. Specific binding was observed in the nuclei of 111 of 163 (68%) tumors. An excellent correlation was observed between the ER-ICA and the estrogen receptor enzyme immunoassay. A significant relationship was observed between ER-ICA status and percentage of ER-ICA negative cells, histological grade of malignancy, and mitotic activity of the tumors. A significant correlation was also observed between ER-ICA status and age at mastectomy with 50% of patients with ER-ICA positive breast tumors presenting with their disease over 60 years of age. No association was observed with either tumor size or patient nodal status. Examination of the proportion of negative cells within tumors revealed a trend for the acquisition of poor prognostic features to be associated with an increase in the negative cell population. Data on the recurrence free interval of these patients showed a significant recurrence free advantage in ER-ICA positive patients, particularly those whose tumors contained low numbers of negative cells.

Automated quantitation of immunocytochemically localized estrogen receptors in human breast cancer.

Frozen sections of breast tumor tissue have been stained using an immunoperoxidase [estrogen receptor (ER)-immunocytochemistry] kit incorporating a monoclonal antiserum [H222] to visualize nuclear human ERs. Quantitation of specific staining has been performed by manual procedures using optical microscopy and by a computer-assisted image analysis system (CAS 100). Initial investigations with a test panel of ER-immunocytochemistry-positive tumors revealed a good qualitative agreement between CAS and manual assessments. Reduced variance was, however, observed between quantified ER-immunocytochemistry results from four experienced investigators using the CAS analysis. An extended study confirmed the relationships between CAS and manual methods of assessment. These findings were evident when studies were scored either by assessment of the percentage of positively stained cells (n = 92; r = 0.919; P less than 0.01) or by H-score calculations (n = 92; r = 0.913; P less than 0.01). A good correlation was also found between CAS quantification and the results of an ER enzyme immunoassay of 48 primary breast cancer specimens (r = 0.715; P less than 0.05). In 49 cases it was possible to relate CAS-defined ER status and levels to the subsequent response of patients to endocrine therapy. ER was assessed on specimens obtained prior to commencement of treatments for recurrent breast cancer. Presuming the presence of ER to be a prerequisite for successful therapy, very good correlations between response and both status and levels of positivity were recorded. None of 16 patients with CAS-ER-negative tumors responded to treatment, while 16 of 33 (48.4%) CAS-ER-positive patients achieved an objective response according to International Union Against Cancer criteria. A relationship between response and the degree of CAS-ER positivity was obtained when the CAS score divisions of 0, 1-100, and greater than 100 (response rates, 0, 41, and 64%, respectively) were used. These data demonstrate that automated image analysis offers a reliable, reproducible procedure for quantifying ER in immunocytochemically stained sections. It has potential advantages over manual procedures, providing less opportunity for subjective influences in scoring sections. Future advances in software design should further reduce elements of subjectivity and increase both the speed and reliability of results. We anticipate image analysis becoming a valuable tool in investigations concerning, for example, the influence of heterogeneity of steroid receptor distribution on the rate of recurrence of breast cancer after mastectomy and in the clinical course of the disease.

Estradiol induction of retinoic acid receptors in human breast cancer cells.

Retinoic acid inhibits proliferation and steroid receptor gene expression in human breast cancer cell lines. Retinoic acid receptors (RAR)alpha, -beta, and -gamma are expressed in these cells and the expression of RAR alpha is significantly greater in estrogen receptor (ER)-positive cells. This study was undertaken to determine whether the same relationship between RAR alpha and ER gene expression was present in human breast cancers and to explore the possibility that the higher level of RAR alpha in ER-positive cells was due to estrogen regulation of RAR alpha gene expression. RAR alpha and ER mRNA expression were determined by Northern blot analysis in 116 primary breast tumors; 94 (81%) tumors were ER-positive and of these 87 (93%) were also RAR alpha-positive. The coexpression of ER and RAR alpha was statistically significant (P = 0.0052 by chi 2 contingency analysis). There was also a positive correlation (by linear regression analysis) between the levels of expression of ER and RAR alpha mRNA (r2 = 0.251, P = 0.0001), which confirmed the relationship previously documented in breast cancer cell lines and suggested that RAR alpha expression may be modulated in breast cancer in vivo by estrogens acting via the ER. The ability of estradiol to regulate RAR alpha gene expression was examined in vitro using T-47D cells which had been rendered sensitive to estrogen by repeated passage in steroid-depleted medium. Estradiol increased RAR alpha gene expression, but not that of RAR beta or RAR gamma, in a concentration-dependent manner, with the effect being maximal at 10(-10) M and less marked at higher concentrations. The effect was rapid, being detectable 1 h after and maximal 6 h after treatment with 10(-10) M estradiol. Co-treatment of cells with estradiol and antiestrogens (tamoxifen or ICI 164384, 4 x 10(-7) M for 6 h) inhibited the estradiol induction of RAR alpha gene expression, demonstrating that the effect was ER mediated. The estradiol sensitivity of the effect was underscored by the demonstration that addition of untreated serum to cells growing under steroid-depleted conditions was sufficient to induce maximal RAR alpha gene expression. This effect was totally abolished by addition of ICI 164384. In summary, the demonstration that estradiol increased RAR alpha mRNA levels in breast cancer cells supports the hypothesis that the correlation between RAR alpha and ER gene expression in breast tumors and breast cancer cell lines is due to estradiol augmentation of RAR alpha gene expression.

Transforming growth factor-alpha and endocrine sensitivity in breast cancer.

The expression of transforming growth factor-alpha (TGF-alpha) has been evaluated in 51 breast cancers of known responsiveness to endocrine therapy using immunohistochemistry. High levels of TGF-alpha were observed in 65% of tumors and showed no relationship with tumor estrogen receptor or epidermal growth factor receptor status or Ki67 immunostaining. TGF-alpha levels did, however, relate to the endocrine sensitivity of the disease, with unresponsive tumors frequently showing high levels of TGF-alpha immunoreactivity. This relationship was observed in estrogen receptor-positive disease and was independent of the epidermal growth factor receptor status of the tumor. No quantitative association between TGF-alpha and Ki67 immunostaining was observed in any of the subcategories of tumors. These data infer a role for TGF-alpha in the development of endocrine insensitivity in estrogen receptor-positive breast cancer by mechanisms which appear independent of tumor growth fraction, as determined by Ki67 immunostaining.

Investigation of a new pure antiestrogen (ICI 182780) in women with primary breast cancer.

We have conducted a clinical trial of a novel pure antiestrogen, 7 alpha-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)nonyl]estra-1,3,5,(1 0)-triene-3,17 beta-diol (ICI 182780), to assess its tolerance, pharmacokinetics, and short term biological effects in women with primary breast cancer. Fifty-six patients were randomized to either a control group (n = 19), in which they received no preoperative treatment, or a treatment group (n = 37), in which they received daily i.m. injections of ICI 182780 at doses of 6 mg (n = 21) or 18 mg (n = 16) for 7 days prior to primary breast surgery. Serum drug concentrations, gonadotropin levels, and sex hormone-binding globulin levels were measured during the study period by radioimmunoassay. Expression of estrogen receptors (ER), progesterone receptors, the estrogen-induced protein pS2, and the cell proliferation-related antigen Ki67 was determined immunocytochemically in pre- and poststudy tumor samples. Treatment with ICI 182780 caused no serious drug-related adverse events and had no effect on serum gonadotropin or sex hormone-binding globulin levels. Minor adverse events occurred in 5 patients receiving the 6-mg dose and 3 patients receiving the 18-mg dose. The serum concentration of ICI 182780 was dose dependent but showed variation between individuals. There was evidence of an approximately 3-fold drug accumulation over the short treatment period but steady state levels were not reached by the end of the 7 days. In patients with ER-positive tumors, treatment with ICI 182780 was associated with significant reductions in the tumor expression of ER (median ER index, 0.72 before versus 0.02 after treatment; P < 0.001), progesterone receptor (median progesterone receptor index, 0.50 before versus 0.01 after treatment; P < 0.05), and Ki67 (median Ki67 labeling index, 3.2 before versus 1.1 after treatment; P < 0.05). Treatment with ICI 182780 also resulted in a significant reduction in pS2 expression (P < 0.05) but this appeared unrelated to tumor ER status. In conclusion, ICI 182780 was well tolerated after short term administration and produced demonstrable antiestrogenic effects in human breast tumors in vivo, without showing evidence of agonist activity. These properties identify ICI 182780 as a candidate agent with which to evaluate whether a pure estrogen antagonist offers any additional benefit in the treatment of human breast cancer over conventional nonsteroidal antiestrogens, typified by tamoxifen, which exhibit variable degrees of agonist activity.

Evaluation of an enzyme immunoassay for estrogen receptors in human breast cancers.

An estrogen receptor enzyme immunoassay kit (ER-EIA) has been evaluated in 70 human breast carcinomas against a routine cytoplasmic [3H]estradiol binding assay (ERU). A linear correlation between the ER-EIA and the ERU was observed for binding values up to 400 fmol/mg of cytosol protein. Above this value, the ERU underestimates the concentration of receptor. The ERU gave a lower number of estrogen receptor-positive tumors (50 of 70) than did the ER-EIA assay (59 of 70). In the ERU-negative ER-EIA-positive tumors, receptor values as determined by the ER-EIA assay all fell below 50 fmol/mg of protein (mean, 19.9 +/- 4.2 fmol/mg of protein). Application of an exchange procedure which estimates the total steroid binding capacity of the cytosol gave positive results in 7 of 9 ERU-negative ER-EIA-positive tumors (mean, 16.9 +/- 2.95 fmol/mg of protein). Subdivision of the binding data according to the menopausal status of the patient indicates low receptor values in premenopausal women by each assay. A correlation between the ER-EIA assay and the histological grade of tumors was observed; Grade I well-differentiated tumors were all positive, while Grade II and III tumors were 86% and 75% positive, respectively. No correlation between the ER-EIA assay and tumor lymph node stage or tumor size was observed.

c-erbB3 and c-erbB4 expression is a feature of the endocrine responsive phenotype in clinical breast cancer.

We examined c-erbB3 and c-erbB4 mRNA expression in 47 primary breast cancer samples by simultaneous RT-PCR and have investigated correlations between these parameters and the expression of both ER and EGFR mRNA and protein as measured by RT-PCR and ICA and with Ki67 immunostaining. A direct association was found between c-erbB3 and c-erbB4 mRNA and ER marker status measured by either RT-PCR (c-erbB3 P = 0.0003; c-erbB4 P = 0.02) or ICA (c-erbB-3 P = 0.002; c-erbB4 P = 0.01). Inverse associations were seen between c-erbB3 and c-erbB4 mRNA marker status and EGFR membrane protein (c-erbB3: P = 0.003; cerbB4: P = 0.003) and mRNA (c-erbB4: P = 0.009) status. These associations were reinforced by Spearman Rank Correlation Tests. A significant relationship was seen between Ki67 and c-erbB4 mRNA status and level. Measurements of c-erbB3 protein levels in tumour samples removed from a further 89 patients of known response to endocrine therapy: (i) confirmed the relationship between c-erbB3 and ER and (ii) identified that patients whose ER positive tumours expressed high levels of c-erbB3 were most likely to benefit from endocrine measures. A non-significant trend was recorded between c-erbB3 levels and Ki67 immunostaining. These results clearly demonstrate that increased c-erbB3 and c-erbB4 expression appears to be associated with the prognostically-favourable ER phenotype.

EMS1 gene expression in primary breast cancer: relationship to cyclin D1 and oestrogen receptor expression and patient survival.

The EMS1 and CCND1 genes at chromosome 11q13 are amplified in about 15% of primary breast cancers but appear to confer different phenotypes in ER positive and ER negative tumours. Since there are no published data on EMS1 expression in large series of breast cancers we examined the relationship of EMS1 expression with EMS1 gene copy number and expression of mRNAs for cyclin D1 and ER. In a subset of 129 patients, where matched tumour RNA and DNA was available, EMS1 mRNA overexpression was associated predominantly with gene amplification (P = 0.0061), whereas cyclin D1 mRNA overexpression was not (P = 0.3142). In a more extensive series of 351 breast cancers, there was no correlation between cyclin D1 and EMS1 expression in the EMS1 and cyclin D1 overexpressors (P = 0.3503). Although an association between EMS1 mRNA expression and ER positivity was evident (P = 0.0232), when the samples were divided into quartiles of EMS1 or cyclin D1 mRNA expression, the increase in the proportion of ER positive tumours in the ascending EMS1 mRNA quartiles was not statistically significant (P = 0.0951). In marked contrast there was a significant stepwise increase in ER positivity in ascending quartiles of cyclin D1 mRNA (P = 0.030). A potential explanation for this difference was provided by the observation that in ER positive breast cancer cells oestradiol treatment resulted in increased cyclin D1 gene expression but was without effect on EMS1. The relationship between EMS1 expression and clinical outcome was examined in a subset of 234 patients with median follow-up of 74 months. High EMS1 expression was associated with age > 50 years (P = 0.0001), postmenopausal status (P = 0.0008), lymph node negativity (P = 0.019) and an apparent trend for worse prognosis in the ER negative subgroup. These data demonstrate that overexpression of EMS1 mRNA is largely due to EMS1 gene amplification, is independent of cyclin D1 and ER expression and, in contrast to cyclin D1, is not regulated by oestrogen. Independent overexpression of these genes may confer different phenotypes and disease outcomes in breast cancer as has been inferred from recent studies of EMS1 and CCND1 gene amplification.

Combined tamoxifen and luteinizing hormone-releasing hormone (LHRH) agonist versus LHRH agonist alone in premenopausal advanced breast cancer: a meta-analysis of four randomized trials.

PURPOSE: The logic behind the application of luteinizing hormone-releasing hormone (LHRH) agonists in combination with tamoxifen in premenopausal women is that LHRH agonists on the one hand suppress the tamoxifen-induced stimulation of the pituitary-ovarian function and, on the other hand, seem as effective as surgical castration. This meta-analysis combines all randomized evidence to compare the combined treatment with LHRH agonist alone with respect to overall survival, progression-free survival, and objective response in premenopausal women with advanced breast cancer. PATIENTS AND METHODS: Four clinical trials randomizing a total of 506 premenopausal women with advanced breast cancer to LHRH agonist alone or to the combined treatment of LHRH agonist plus tamoxifen were identified. Meta-analytic techniques were used to analyze individual patient data from these trials. RESULTS: With a median follow-up of 6.8 years, there was a significant survival benefit (stratified log-rank test, P = .02; hazards ratio [HR] = 0.78) and progression-free survival benefit (stratified log-rank test, P = .0003; HR = 0.70) in favor of the combined treatment. The overall response rate was significantly higher on combined endocrine treatment (stratified Mantel Haenszel test, P = .03; odds ratio = 0.67). CONCLUSION: The combination of LHRH agonist plus tamoxifen is superior to LHRH agonist alone in premenopausal women with advanced breast cancer. Therefore, if a premenopausal woman with advanced breast cancer is thought to be suitable for endocrine treatment, it is proposed that the combination of a LHRH agonist plus tamoxifen be considered as the new standard treatment.

A randomized comparison of tamoxifen with surgical oophorectomy in premenopausal patients with advanced breast cancer.

We randomized 122 premenopausal women to receive tamoxifen or to undergo a surgical oophorectomy. Of 54 evaluable women treated with tamoxifen, 24% had an objective response, as compared with 21% of 53 women having an oophorectomy. The median duration of response for tamoxifen (20 months) was longer than that for surgical oophorectomy (7 months), but this did not achieve statistical significance (P = .056). Overall median survival was 15 months for 58 patients receiving tamoxifen and 25 months for 53 patients undergoing oophorectomy (P = .18). Toxicity was greater in those undergoing oophorectomy, though both treatments were well tolerated. In those premenopausal women for whom hormonal therapy is indicated, tamoxifen is a suitable alternative to surgical oophorectomy.

Cyclin D1 and estrogen receptor messenger RNA levels are positively correlated in primary breast cancer.

The CCND1 gene, encoding the cell cycle regulatory protein cyclin D1, maps to chromosome 11q13, a locus that is amplified in about 13% of breast cancers. Because several studies have indicated a relationship between 11q13 amplification and markers of phenotype including estrogen receptor (ER) status, we tested the relationship between CCND1 and ER gene expression in 364 primary breast cancers using Northern blot analysis. Seventy-three % of samples were positive for ER mRNA, and cyclin D1 mRNA levels in the ER-positive group were significantly higher than those in the ER-negative group (P = 0.0001). When the samples were divided into quartiles of cyclin D1 expression, 58% of samples were ER positive in the lowest quartile and 87% in the highest quartile. The tumors expressing the highest levels of cyclin D1 (7%) were all ER positive. Furthermore, ER mRNA levels in the half with lower cyclin D1 mRNA were significantly less than in the half with higher cyclin D1 levels (P = 0.0001). Using simple regression analysis, there was a significant positive correlation between cyclin D1 and ER mRNA levels in the total population (P = 0.0001). This study demonstrates that cyclin D1 mRNA and ER mRNA are positively correlated in primary breast cancer, but the functional relationship between these genes remains to be elucidated.