Change in expression of ER, bcl-2 and MIB1 on primary tamoxifen and relation to response in ER positive breast cancer

Hormone Receptor Down-Regulation in Metastatic Breast Cancer After Endocrine Therapy Detected Oophorectomy: A Case Report and Review of Literature

Globally, breast cancer is the most frequently diagnosed malignancy among women; it is also one of the leading causes of cancer mortality among females. The most common sites for metastases are the lungs, bones, liver, and brain. Breast cancer is recognized as one of the most common primary sites of metastatic lesions in the ovaries and is often associated with multiple extra-ovarian metastases. Here, we report a case of occult breast cancer metastases to the ovaries with a down-regulated hormonal immunohistochemistry profile after endocrine therapy, encountered incidentally after oophorectomy.

Clinical evaluation of BCL-2/XL levels pre- and post- HER2-targeted therapy

Our previous pre-clinical work defined BCL-2 induction as a critical component of the adaptive response to lapatinib-mediated inhibition of HER2. To determine whether a similar BCL-2 upregulation occurs in lapatinib-treated patients, we evaluated gene expression within tumor biopsies, collected before and after lapatinib or trastuzumab treatment, from the TRIO-B-07 clinical trial (NCT#00769470). We detected BCL2 mRNA upregulation in both HER2+/ER- as well as HER2+/ER+ patient tumors treated with lapatinib or trastuzumab. To address whether mRNA expression correlated with protein expression, we evaluated pre- and post-treatment tumors for BCL-2 via immunohistochemistry. Despite BCL2 mRNA upregulation within HER2+/ER- tumors, BCL-2 protein levels were undetectable in most of the lapatinib- or trastuzumab-treated HER2+/ER- tumors. BCL-2 upregulation was evident within the majority of lapatinib-treated HER2+/ER+ tumors and was often coupled with increased ER expression and decreased proliferation. Comparable BCL-2 upregulation was not observed within the trastuzumab-treated HER2+/ER+ tumors. Together, these results provide clinical validation of the BCL-2 induction associated with the adaptive response to lapatinib and support evaluation of BCL-2 inhibitors within the context of lapatinib and other HER2-targeted receptor tyrosine kinase inhibitors.

A multicenter phase II trial of neoadjuvant letrozole plus low-dose cyclophosphamide in postmenopausal patients with estrogen receptor-positive breast cancer (JBCRG-07): therapeutic efficacy and clinical implications of circulating endothelial cells

Neoadjuvant endocrine therapy has been reported to decrease tumor size, which leads to increased breast conservation rates. To improve the clinical response, metronomic chemotherapy with endocrine therapy is a promising strategy. A multicenter phase II single‐arm neoadjuvant trial with letrozole and cyclophosphamide was conducted. Eligibility criteria included postmenopausal status, T2–4 N0–1, and estrogen receptor‐positive breast carcinoma. Letrozole (2.5 mg) plus cyclophosphamide (50 mg) was given orally once a day for 24 weeks. The primary endpoint was the clinical response rate (CRR). To investigate anti‐angiogenic effects, circulating endothelial cells (CECs) were quantified using the CellSearch system. From October 2007 to March 2010, 41 patients were enrolled. The CRR was 67.5% (52.0–80.0%), which was above the prespecified threshold (65%). The conversion rate from total mastectomy to breast‐conserving surgery was 64% (18/28). Grade 3 or greater nonhematological toxicity was not reported. Clinical response was associated with improved disease‐free survival (DFS) (P = 0.020). The increase in CEC counts at 8 weeks was observed in nonresponders (P = 0.004) but not in responders. Patients with higher CEC counts at baseline or post‐treatment showed worse DFS than those with lower counts (P < 0.001 at baseline and = 0.014 post‐treatment). Multivariate analysis showed that post‐treatment CEC counts but not pretreatment counts were independently correlated with DFS (P = 0.046). In conclusion, neoadjuvant letrozole plus cyclophosphamide showed a good clinical response for postmenopausal patients with estrogen receptor‐positive breast cancer. CEC quantification is a promising tool for treatment monitoring and prognostic stratification for metronomic therapy following validation of our results in larger studies. Clinical trial registration number: UMIN000001331 Phase II study of neoadjuvant letrozole combined with low‐dose metronomic cyclophosphamide for postmenopausal women with endocrine‐responsive breast cancer (JBCRG‐07)

Antihormone induced compensatory signalling in breast cancer: an adverse event in the development of endocrine resistance

Using MCF7 breast cancer cells, it has been shown that antihormones promote expression/activity of oestrogen-repressed tyrosine kinases, notably EGFR, HER2 and Src. These inductive events confer responsiveness to targeted inhibitors (e.g., gefitinib, trastuzumab, saracatinib). We observed that these antihormone-induced phenomena are common to ER+HER2- and ER+HER2+ breast cancer models in vitro, where targeting of EGFR, HER2 or Src alongside antihormone improves antitumour response and delays/prevents endocrine resistance. Such targeted inhibitors also subvert acquired endocrine resistant cells which retain increased EGFR, HER2 and Src (e.g., TAMR and FASR models derived after 6-12 months of tamoxifen or Faslodex treatment). Thus, antihormone-induced tyrosine kinases comprise "compensatory signalling" crucial in limiting maximal initial antihormone response and subsequently driving acquired resistance in vitro. However, despite such convincing preclinical findings from our group and others, clinical trials examining equivalent antigrowth factor strategies have proved relatively disappointing. Our new studies deciphering underlying causes reveal that further antihormone-promoted events could be pivotal in vivo. Firstly, Faslodex induces HER3 and HER4 which sensitise ER+ cells to heregulin, a paracrine growth factor that overcomes endocrine response and diminishes antitumour effect of agents targeting EGFR, HER2 or Src alongside antihormone. Secondly, extended antihormone exposure (experienced by ER+ cells prior to adjuvant clinical relapse) can "reprogramme" the compensatory kinase profile in vitro, hindering candidate antigrowth factor targeting of endocrine resistance. Faslodex resistant cells maintained with this antihormone for 3 years in vitro lose EGFR/HER2 dependency, gaining alternative mitogenic/invasion kinases. Deciphering these previously unrecognised antihormone-induced events could provide superior treatments to control endocrine relapse in the clinic.

BCL-2 hypermethylation is a potential biomarker of sensitivity to antimitotic chemotherapy in endocrine-resistant breast cancer

Overexpression of the antiapoptotic factor BCL-2 is a frequent feature of malignant disease and is commonly associated with poor prognosis and resistance to conventional chemotherapy. In breast cancer, however, high BCL-2 expression is associated with favorable prognosis, estrogen receptor (ER) positivity, and low tumor grade, whereas low expression is included in several molecular signatures associated with resistance to endocrine therapy. In the present study, we correlate BCL-2 expression and DNA methylation profiles in human breast cancer and in multiple cell models of acquired endocrine resistance to determine whether BCL-2 hypermethylation could provide a useful biomarker of response to cytotoxic therapy. In human disease, diminished expression of BCL-2 was associated with hypermethylation of the second exon, in a region that overlapped a CpG island and an ER-binding site. Hypermethylation of this region, which occurred in 10% of primary tumors, provided a stronger predictor of patient survival (P = 0.019) when compared with gene expression (n = 522). In multiple cell models of acquired endocrine resistance, BCL-2 expression was significantly reduced in parallel with increased DNA methylation of the exon 2 region. The reduction of BCL-2 expression in endocrine-resistant cells lowered their apoptotic threshold to antimitotic agents: nocodazole, paclitaxel, and the PLK1 inhibitor BI2536. This phenomenon could be reversed with ectopic expression of BCL-2, and rescued with the BCL-2 inhibitor ABT-737. Collectively, these data imply that BCL-2 hypermethylation provides a robust biomarker of response to current and next-generation cytotoxic agents in endocrine-resistant breast cancer, which may prove beneficial in directing therapeutic strategy for patients with nonresectable, metastatic disease.

Prognostic significance of Ki-67 labeling index after short-term presurgical tamoxifen in women with ER-positive breast cancer

BACKGROUND

Studies have shown that Ki-67 response after short-term neoadjuvant aromatase inhibitors may predict recurrence in postmenopausal breast cancer, whereas its prognostic effect in premenopausal women is unknown.

PATIENTS AND METHODS

We compared the prognostic and predictive value of baseline and post-treatment Ki-67 in 120 pre- and postmenopausal women with early-stage estrogen receptor-positive breast cancer who participated in a 4-week presurgical trial of tamoxifen.

RESULTS

After 7.2 years of follow-up, women with post-treatment Ki-67 in the second (14%-19%), third (20%-29%) and top (≥30%) quartiles had a recurrence hazard ratio of 2.92 [95% confidence interval (CI) 0.95-8.96], 4.37 (1.56-12.25) and 6.05 (2.07-17.65), respectively, as compared with those in the bottom quartile (<14%) (P-trend = 0.001). The risk of invasive disease recurrence was 2.2% (95% CI 0.9-5.0) per point increase in baseline Ki-67 (P-trend = 0.076) and 5.0% (95% CI 2.3-7.7) per point increase in post-tamoxifen Ki-67 (P-trend < 0.001). The risk of death was 5.5 (95% CI 1.26-23.16) times higher in patients with post-drug Ki-67 ≥20% than in those with Ki-67 <20% (P-trend = 0.006).

CONCLUSIONS

Ki-67 response after short-term neoadjuvant tamoxifen is a good predictor of recurrence-free survival and overall survival, further supporting its use as surrogate biomarker to personalize adjuvant treatment and to screen novel drugs cost-effectively.

The effects of gefitinib in tamoxifen-resistant and hormone-insensitive breast cancer: a phase II study

Estrogen receptor (ER)-positive acquired tamoxifen-resistant (TAM-R) MCF-7 breast cancer cell lines exhibit epidermal growth factor receptor (EGFR) expression/signaling and are growth-inhibited by gefitinib (IRESSA). We examined the effect of gefitinib on ER-positive TAM-R and ER-negative hormone-insensitive breast cancer in a Phase II study. Fifty-four patients with breast cancer [ER-positive/acquired TAM-R (n = 28); ER-negative (n = 26)] received oral gefitinib 500 mg/day. Tumor biopsies were taken pre- (n = 28) and 8 weeks post-treatment (n = 14 matched samples). Gefitinib was well tolerated and the clinical benefit rate (objective response or stable disease >24 weeks) was 33.3% overall (n = 18/54), and 53.6 and 11.5% in ER-positive/TAM-R and ER-negative patients, respectively. Pretreatment ER and progesterone receptor-positivity were associated with response (p < 0.001 and 0.016, respectively) and longer progression-free survival (PFS; p= 0.001 and 0.013, respectively). All patients expressed EGFR, but high pretreatment levels predicted poorer outcome (p = 0.005) and shorter PFS (p = 0.012) with gefitinib. In patients with clinical benefit, reduced Ki67 staining during treatment (p = 0.024) was commonly observed, and those with >10% decline in EGFR phosphorylation demonstrated parallel decreases in ERK1/2 MAPK phosphorylation. Acquired tamoxifen resistance appears in part mediated through EGFR signaling and can be blocked with gefitinib.

Fulvestrant (Faslodex) -- how to make a good drug better

Fulvestrant (Faslodex); AstraZeneca Pharmaceuticals, Wilmington, DE) is an estrogen receptor (ER) antagonist with a novel mode of action; it binds, blocks, and increases degradation of ER. Fulvestrant (at the approved dose [250 mg/month]) is at least as effective as anastrozole (1 mg/day) in the treatment of postmenopausal women with hormone receptor-positive advanced breast cancer (HR(+) ABC) progressing or recurring on antiestrogen therapy, and is also an active first-line treatment. Although fulvestrant (250 mg/month) is clearly effective, it takes 3-6 months to achieve steady-state plasma levels. Steady-state concentrations are approximately twofold higher than those achieved with a single dose; reaching this earlier, for example, via a loading-dose (LD) regimen (250 mg/month plus 500 mg on day 0 and 250 mg on day 14 of month 1), may allow responses to be achieved more quickly and limit the possibility of early relapse. Fulvestrant high-dose (HD) regimens (500 mg/month) offer the possibility of greater antitumor activity, because (a) ER downregulation is a dose-dependent process (an approximately 70% reduction is observed with a single 250 mg dose of fulvestrant) and (b) evidence correlates greater ER downregulation with superior efficacy. A fulvestrant HD regimen offers the potential of achieving near 100% ER downregulation. There is also potential to increase fulvestrant-ER binding by reducing plasma estrogen levels, for example, with concomitant aromatase inhibitor treatment. Several ongoing trials use LD, HD, and combination regimens; results from these studies are awaited with interest. Meanwhile, fulvestrant (250 mg/month) remains a valuable additional endocrine treatment for postmenopausal women with HR(+) ABC recurring or progressing on antiestrogen therapy.

CCND1 amplification and cyclin D1 expression in breast cancer and their relation with proteomic subgroups and patient outcome

INTRODUCTION

Despite strong evidence regarding the role of CCND1 amplification and protein overexpression in breast carcinoma, the associations between CCND1 amplification/cyclin D1 overexpression and clinicopathological variables and clinical outcome remain controversial.

AIMS OF THE STUDY

(1) to correlate cyclin D1 expression with gene amplification; (2) to analyse the correlations between CCND1 amplification and overexpression with clinicopathological features and patients' outcome in invasive breast cancer; (3) to define the prevalence and clinical significance of cyclin D1 overexpression and CCND1 amplification in ER positive breast carcinomas (4) to define the prevalence of cyclin D1 overexpression and CCND1 amplification in breast cancers with basal-like immunophenotype.

MATERIALS AND METHODS

CCND1 amplification and protein expression were assessed on a tissue microarray containing 880 unselected invasive breast cancer cases, by means of chromogenic in situ hybridisation using the Spotlight CCND1 amplification probe and immunohistochemistry, using the rabbit monoclonal antibody SP4.

RESULTS

A total of 59/613 tumours (9.6%) showed CCND1 amplification and 224/514 (43.6%) showed strong cyclin D1 expression. A strong positive correlation between CCND1 amplification and higher levels of cyclin D1 expression was found (P < 0.001). Basal-like cancers showed infrequent CCND1 amplification and cyclin D1 overexpression (P < 0.001). Both CCND1 amplification and cyclin D1 expression were associated with positive ER status. CCND1 gene amplification was an independent prognostic factor for patients with ER positive breast cancer.

CONCLUSION

Our results demonstrate a strong correlation between CCND1 amplification and its protein expression in breast cancer. However, protein expression is more pervasive than gene amplification and associated with ER expression.

Pre-clinical validation of early molecular markers of sensitivity to aromatase inhibitors in a mouse model of post-menopausal hormone-sensitive breast cancer

INTRODUCTION

Changes in breast cancer cell biology following hormonal treatment have been claimed as promising predictor markers of clinical benefit even outperforming clinical response. From previous work we selected 10 genes showing both a well known regulation by oestrogen and a high level of early transcriptional regulation following therapy with aromatase inhibitors. Here we use an animal breast cancer model to explore the feasibility of the determination of their expression in minimally invasive samples and to further assess the magnitude of their regulation by letrozole. ANIMAL AND METHODS: Aromatase inhibitor sensitive breast cancer tumours were grown in athymic mice under supplement with androstenedione. Following initial tumour growth animals were assigned to a control group or to receive letrozole at two different dosages. Fine needle aspirates were obtained at the moment of treatment assignation and one week later. Expression of the following genes at both time points was determined: Ki-67, Cyclin D1, pS2, Trefoil Factor 3, PDZ domain containing 1, Ubiquitin-conjugating enzyme E2C, Stanniocalcin 2, Topoisomerase 2 alfa, MAN1A1 and FAS.

RESULTS

Fine needles aspirates were found to be a feasible and reproducible technique for RNA extraction. Trefoil Factor 3, pS2, Cyclin D1 and Stanniocalcin 2 were significantly downregulated by letrozole. Among them pS2 appears to be most sensitive to aromatase inhibitor treatment even differentiating sub-optimal from optimal letrozole dosage.

DISCUSSION

We present pre-clinical evidence to justify the exploration in clinical trials of pS2, Trefoil factor 3, Cyclin D1 and Stanniocalcin as dynamic markers of oestrogen-driven pathway activation.

Investigating the mechanism of enhanced cytotoxicity of HPMA copolymer–Dox–AGM in breast cancer cells

Recently we have described an HPMA copolymer conjugate carrying both the aromatase inhibitor aminoglutethimide (AGM) and doxorubicin (Dox) as combination therapy. This showed markedly enhanced in vitro cytotoxicity compared to the HPMA copolymer-Dox (FCE28068), a conjugate that demonstrated activity in chemotherapy refractory breast cancer patients during early clinical trials. To better understand the superior activity of HPMA copolymer-Dox-AGM, here experiments were undertaken using MCF-7 and MCF-7ca (aromatase-transfected) breast cancer cell lines to: further probe the synergistic cytotoxic effects of AGM and Dox in free and conjugated form; to compare the endocytic properties of HPMA copolymer-Dox-AGM and HPMA copolymer-Dox (binding, rate and mechanism of cellular uptake); the rate of drug liberation by lysosomal thiol-dependant proteases (i.e. conjugate activation), and also, using immunocytochemistry, to compare their molecular mechanism of action. It was clearly shown that attachment of both drugs to the same polymer backbone was a requirement for enhanced cytotoxicity. FACS studies indicated both conjugates have a similar pattern of cell binding and endocytic uptake (at least partially via a cholesterol-dependent pathway), however, the pattern of enzyme-mediated drug liberation was distinctly different. Dox release from PK1 was linear with time, whereas the release of both Dox and AGM from HPMA copolymer-Dox-AGM was not, and the initial rate of AGM release was much faster than that seen for the anthracycline. Immunocytochemistry showed that both conjugates decreased the expression of ki67. However, this effect was more marked for HPMA copolymer-Dox-AGM and, moreover, only this conjugate decreased the expression of the anti-apoptotic protein bcl-2. In conclusion, the superior in vitro activity of HPMA copolymer-Dox-AGM cannot be attributed to differences in endocytic uptake, and it seems likely that the synergistic effect of Dox and AGM is due to the kinetics of intracellular drug liberation which leads to enhanced activity.

Overexpression of c-Myc and Bcl-2 during progression and distant metastasis of hormone-treated breast cancer

The aim of this study was to identify molecules involved in the proliferation and survival of recurrent estrogen receptor (ER)-positive breast cancer at the site of metastasis. Most studies of biomarkers are done using the initial primary breast tumor whereas pathological studies of breast cancer lesions after distant recurrence are scarce. Here we evaluated the expression of the oncogenes c-Myc and Bcl-2, mediators of estrogen-dependent proliferation and survival, during breast cancer progression and relapse after adjuvant hormonal therapy. Using a preclinical model of tamoxifen-resistant growth, we found overexpression of c-Myc in all (3/3) and of Bcl-2 in most (2/3) tamoxifen resistant-breast cancer variants. To determine whether c-Myc and Bcl-2 are expressed during breast cancer progression in the clinics we identified breast cancer patients who had received adjuvant hormonal therapy for the treatment of their localized disease and had later experienced relapse. From 583 patients who had received adjuvant hormonal therapy a total of 82 experienced recurrence. Nevertheless, only 22 patients had had a biopsy of their metastatic lesion done after relapse. Twenty-one biopsies were useful for this biomarker study. These biopsies were obtained mostly (20) from breast cancer patients who had received tamoxifen as their adjuvant hormonal therapy. One patient had received an aromatase inhibitor instead. Our results showed that almost all (20) metastatic recurrences expressed ER. Expression of c-Myc was observed in 18 out of 19 metastatic lesions scored while expression of Bcl-2 was detected in 17 out of 21 metastatic tumors. A correlation between ER expression and Bcl-2, but not with c-Myc, was found in these recurrent metastatic lesions. In addition, c-Myc expression was correlated with the nuclear grade of the metastatic lesion. Thus, the frequent expression of c-Myc and Bcl-2 in metastatic breast cancer recurrences suggests that combining hormonal therapy with strategies to block c-Myc and Bcl-2 may prevent growth of ER-positive breast cancer at the site of metastasis.

Differential expression of Bcl-2, Bcl-XL and p53 in colorectal cancer

AIMS

The balance between proliferation and apoptosis is often disturbed in cancer. The aim of this study was to investigate the possible role of Bcl-2 gene family members and p53 as prognostic factors in a series of colorectal cancer.

METHODS

The immunohistochemical expression of Bcl-2 gene family members (Bcl-2 and Bcl-X(L)) and p53 was evaluated in 81 surgical specimens of primary human colorectal cancers to establish the role of these genes in colorectal cancer and to evaluate their prognostic importance.

RESULTS

The expression of Bcl-2 correlated with early clinical stage and lack of lymphovascular invasion and lymph node involvement. The expression of p53 correlated with less differentiated status and with perineural invasion. p53 expression showed negative correlation with Bcl-X(L) expression (P = 0.025) and no correlation with Bcl-2 expression.

CONCLUSIONS

p53 expression may be a less favorable marker and Bcl-2 expression a more favorable marker of behavior. Bcl-2 and Bcl-X(L) may play an independent role in disease progression, and the expression of these proteins may be under independent regulatory control in colorectal cancer.

Proliferation marker Ki-67 in early breast cancer

Molecular markers have been extensively investigated with a view to providing early and accurate information on long-term outcome and prediction of response to treatment of early breast cancer. Proliferation is a key feature of the progression of tumors and is now widely estimated by the immunohistochemical assessment of the nuclear antigen Ki-67. The expression of Ki-67 correlates with other measurements of proliferation, including S-phase and bromodeoxyuridine uptake. High Ki-67 is a sign of poor prognosis associated with a good chance of clinical response to chemotherapy, but its independent significance is modest and does not merit measurements in most routine clinical scenarios. However, its application as a pharmacodynamic intermediate marker of the effectiveness of medical therapy holds great promise for rapid evaluation of new drugs.

Expression of vascular endothelial growth factor and proliferation marker MIB1 are influenced by neoadjuvant chemotherapy in locally advanced breast cancer

Neoadjuvant chemotherapy (NACT) has become the standard of care for patients with locally advanced breast cancer (LABC). This was a retrospective review of 21 consecutive women who received NACT as initial treatment of LABC, followed by surgical excision. The pre- and post-treatment breast specimens and post-treatment axillary lymph nodes with metastases were immunostained to evaluate for proliferative index (PI) (MIB-1 Immunotech) and vascular endothelial growth factor (VEGF) expression (Santa Cruz, CA, clone A-20). Thirteen of the 21 patients (62%) had more than 50% tumor shrinkage following NACT. The breast's mean PI decreased from 47.86% to 23.95% after treatment (P = 0.005). The mean PI in the post-treatment lymph nodes was 24.47%. A nodal post-NACT PI of less than 10% and progesterone receptor-positive tumor status were associated with better survival, as all such patients are alive. A high PI after NACT was associated with recurrence or death. All of the patients who showed an excellent clinical response had either a decrease in the PI or an absence of a high level of VEGF after NACT. Most patients exhibited persistent expression of VEGF after NACT. Pathologic response in the primary tumor did not correlate with the response in the lymph nodes or with overall survival. NACT reduces the size and PI of the primary breast tumor independent of the patient's node status. The PI may be an early means by which to identify tumors most likely to reduce in size with chemotherapy. A low PI after NACT is associated with better survival. There is persistent expression of VEGF in post-NACT residual breast carcinoma. Thus, anti-VEGF drugs after conventional chemotherapy may benefit patients with residual carcinoma.

Prognostic value of proliferation in invasive breast cancer: a review

Breast cancer is the leading cause of death among solid tumours in women, and its incidence is increasing in the West. Adjuvant chemotherapy and hormonal treatment improve survival but have potentially serious side effects, and are costly. Because adjuvant treatment should be given to high risk patients only, and traditional prognostic factors (lymph node status, tumour size) are insufficiently accurate, better predictors of high risk and treatment response are needed. Invasive breast cancer metastasises haematogenously very early on, so many breast cancer prognosticators are directly or indirectly related to proliferation. Although studies evaluating the role of individual proliferation regulating genes have greatly increased our knowledge of this complex process, the functional end result-cells dividing-has remained the most important prognostic factor. This article reviews the prognostic value of different proliferation assays in invasive breast cancer, and concludes that increased proliferation correlates strongly with poor prognosis, irrespective of the methodology used. Mitosis counting provides the most reproducible and independent prognostic value, and Ki67/MIB1 labelling and cyclin A index are promising alternatives that need methodological fine tuning.

Clinicopathological study of the expression of hsp27, pS2, cathepsin D and metallothionein in primary invasive breast cancer

Expression of the hormone-related proteins hsp27, pS2, and also of cathepsin D (CD) and metallothionein (MT) was studied by immunohistochemistry and analyzed against clinical data in breast cancer. Archived material of paraffin-embedded breast carcinoma tissues from a cohort of 134 patients with primary invasive breast cancer was used. Hsp27 and pS2 (>10% of tumor cells stained) were found to be expressed in 63.6% and 37.6% of cases, respectively, and were correlated negatively with grading (P=0.006 and 0.01) and positively with estrogen receptors (ER) (P=0.04 and 0.04). pS2 expression was correlated with lymph node status (P=0.02), tumor size (P=0.01), progesterone receptor (PR) content (P=0.02), hsp27 (P=0.015) and bcl-2 protein (P=0.001). An inverse relationship between pS2 expression and the expression of p53 protein (P=0.005) and proliferation-associated index MIB1 (P<0.0001) was noted. Stromal cathepsin D was positively correlated with tumor grade (P=0.01), PCNA (P=0.007), MIB1 (P=0.001) and p53 (P=0.01), and negatively with ER (P=0.04) and bcl-2 (P<0.0001). MT was correlated positively with stromal CD (P=0.007) and inversely with PgR (P=0.04). Univariate analysis showed CD expression to be a positive prognostic factor for survival (P=0.035), with borderline significance, while MT was more strongly positive (P=0.01). However, none of the proteins studied was found to be related to disease outcome in univariate analysis. Our data show that hsp27, pS2 and stromal CD expression may reflect tumor differentiation and the functional status of ER in breast cancer, but stromal CD and tumor MT expression were the only factors found that may be of limited prognostic value.

The antiepidermal growth factor receptor agent gefitinib (ZD1839/Iressa) improves antihormone response and prevents development of resistance in breast cancer in vitro

Although many estrogen receptor-positive breast cancers initially respond to antihormones, responses are commonly incomplete with resistance ultimately emerging. Delineation of signaling mechanisms underlying these phenomena would allow development of therapies to improve antihormone response and compromise resistance. This in vitro investigation in MCF-7 breast cancer cells examines whether epidermal growth factor receptor (EGFR) signaling limits antiproliferative and proapoptotic activity of antihormones and ultimately supports development of resistance. It addresses whether the anti-EGFR agent gefitinib (ZD1839/Iressa; TKI: 1 mum) combined with the antihormones 4-hydroxytamoxifen (TAM: 0.1 mum) or fulvestrant (Faslodex; 0.1 mum) enhances growth inhibition and prevents resistance. TAM significantly suppressed MCF-7 growth over wk 2-5, reducing proliferation detected by immunocytochemistry and fluorescence-activated cell sorter cell cycle analysis. A modest apoptotic increase was observed by fluorescence-activated cell sorter and fluorescence microscopy, with incomplete bcl-2 suppression. EGFR induction occurred during TAM response, as measured by immunocytochemistry and Western blotting, with EGFR-positive, highly proliferative resistant growth subsequently emerging. Although TKI alone was ineffective on growth, TAM plus TKI cotreatment exhibited superior antigrowth activity vs. TAM, with no viable cells by wk 12. Cotreatment was more effective in inhibiting proliferation, promoting apoptosis, and eliminating bcl-2. Cotreatment blocked EGFR induction, markedly depleted ERK1/2 MAPK and protein kinase B phosphorylation, and prevented emergence of EGFR-positive resistance. Faslodex plus TKI cotreatment was also a superior antitumor strategy. Thus, increased EGFR evolves during treatment with antihormones, limiting their efficacy and promoting resistance. Gefitinib addition to antihormonal therapy could prove more effective in treating estrogen receptor-positive breast cancer and may combat development of resistance.

Studies of the Potential Utility of Ki67 as a Predictive Molecular Marker of Clinical Response in Primary Breast Cancer

INTRODUCTION

Objectives were to characterise the relationship of the proliferation marker Ki67 with response to systemic treatment in early breast cancer and to assess its clinical utility, using fine needle aspirates.

MATERIALS AND METHODS

Hundred and six women were treated with primary tamoxifen (n = 33), chemotherapy (n = 33) or chemotherapy and tamoxifen (n = 40). Treatment was not randomised and response was assessed clinically. Ki67 was evaluated prior to treatment and at Day 14 or 21 after commencing treatment. To assess reproducibility, Ki67 was evaluated in repeat FNAs taken from 37 untreated patients.

RESULTS

The percentage change in Ki67 in first 21 days was different between responders and non-responders for patients treated with tamoxifen (p = 0.007) and chemotherapy (p = 0.005) but not for chemoendocrine treatment (p = 0.062). The reproducibility study indicated that a decrease to 36% or less of the pre-treatment Ki67 value in an individual patient was required for it to be regarded as a statistically significant change. A significant decrease in Ki67 was seen in responding patients treated with chemotherapy (p = 0.026) and chemoendocrine treatment (p = 0.041). Positive and negative predictive values for response were 85 and 59% for chemotherapy patients and 88 and 54% for chemoendocrine patients, respectively.

CONCLUSION

Ki67 is unlikely to be useful as a predictive marker in individual patients. Further molecular markers that predict lack of response continue to be required.

Measurement of proliferation marker Ki67 in breast tumour FNAs using laser scanning cytometry in comparison to conventional immunocytochemistry

BACKGROUND

A variety of markers, including Ki67, estrogen receptors (ER), and progesterone receptors (PgR), are frequently measured in fine needle aspirates from human breast carcinomas. Previously, we demonstrated the use of laser scanning cytometry (LSC) for the measurement of Ki67, ER, and PgR in a human breast carcinoma cell line, MCF7 (21). In the present study, we investigated the expression of Ki67 in breast tumour fine needle aspirates (FNAs) using LSC and compared the results to the data obtained using conventional immunocytochemistry (ICC).

METHODS

A total of 11 sets of cytospins of FNAs taken from breast tumours at various stages of tamoxifen treatment were used. For LSC, the cytospins were stained for Ki67 with fluorescein using immunofluorescence; the nuclei were counterstained with propidium iodide. A parallel set of cytospins was stained using horseradish peroxidase and diaminobenzidine and scored manually by conventional light microscopy.

RESULTS

Values for Ki67 obtained using the LSC were generally lower than ICC scores. The changes in Ki67 measured by the LSC were almost all parallel to those obtained by manual scoring of immunocytochemical stains.

CONCLUSIONS

It should be possible to use LSC for the routine measurement of Ki67 marker in FNAs from human breast carcinomas.

A randomized trial of low-dose tamoxifen on breast cancer proliferation and blood estrogenic biomarkers

BACKGROUND

Tamoxifen reduces the risk of breast cancer in women at high risk for the disease but increases the risk for endometrial tumors and venous thromboembolisms, possibly in a dose-dependent fashion. We compared the effects of tamoxifen at 1 mg/day and 5 mg/day with those of the standard dose of 20 mg/day on breast cancer proliferation using a surrogate endpoint marker (Ki-67 expression) and blood biomarkers associated with breast cancer, cardiovascular disease, and bone fracture risk.

METHODS

We randomly assigned 120 women with estrogen receptor (ER)-positive breast cancer to tamoxifen at 1, 5, or 20 mg/day for 4 weeks. Expression of the tumor proliferation marker Ki-67 and of biomarkers of breast cancer (insulin-like growth factor-I, sex hormone-binding globulin), cardiovascular disease (cholesterol, triglycerides, ultrasensitive C-reactive protein, fibrinogen, antithrombin-III), and bone fracture (type I collagen C-telopeptide) risk were determined before (baseline) and after treatment. All levels were compared with those in two nonrandomized control groups (34 women with ER-negative breast cancer and 29 additional women with ER-positive breast cancer). Data were analyzed by analysis of covariance. All statistical tests were two-sided.

RESULTS

Expression of Ki-67 decreased in all three tamoxifen groups, with no difference in the magnitude of reduction among groups (P =.81). Relative to baseline, Ki-67 expression decreased by a median of 15.0% (95% confidence interval = 0.0% to 24.1%) among the tamoxifen groups but increased by 12.8% (95% confidence interval = 0.0% to 19.6%) among the nonrandomized control groups. Several blood biomarkers showed dose-response relationships with tamoxifen, including decreased insulin-like growth factor-I, increased sex hormone-binding globulin, and decreased low-density lipoprotein-cholesterol, ultrasensitive C-reactive protein, fibrinogen, and antithrombin-III levels.

CONCLUSIONS

The effects on Ki-67 expression of lower doses of tamoxifen were comparable to those achieved with the standard dose, although the effects on blood biomarkers were variable. The effects of lower doses of tamoxifen should be assessed further in randomized trials.

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.