Topoisomerase IIα gene status and prediction of pathological complete remission after anthracycline-based neoadjuvant chemotherapy in endocrine non-responsive Her2/neu-positive breast cancer

Comprehensive evaluation of the relationship between biomarker profiles and neoadjuvant chemotherapy outcomes for breast cancer patients

BACKGROUND

Accurately predicting the response to neoadjuvant chemotherapy (NAC) in breast cancer patients is crucial for guiding treatment strategies and enhancing clinical outcomes. Current studies have primarily focused on a limited set of biomarkers. More importantly, the results of many studies are in conflict. To address this, we conducted a comprehensive evaluation of the predictive value of a diverse range of clinically available molecular biomarkers in breast cancer, including HER2, ER, PR, TOPO II, EGFR, Ki67, CK5/6, AR, and p53. Additionally, we assessed changes in these biomarkers after NAC administration.

METHODS

Our study involved 189 patients with invasive breast cancer who underwent NAC at our institute. We examined biomarker profiles in core-needle biopsies taken before NAC and in surgical specimens obtained after NAC. We examined the association between these biomarkers and NAC outcomes, focusing on two main aspects: the rate of pathological complete response (pCR) and the reduction in tumor size. We used Chi-square and Mann-Whitney U tests to compare biomarker status changes between pCR and non-pCR patients. Linear regression analysis was employed to evaluate the relationship between biomarker status and tumor shrinkage rate. Additionally, we compared the expression status of these biomarkers before and after NAC using Chi-square and Wilcoxon signed-rank tests.

RESULTS AND CONCLUSIONS

Our results demonstrated significant differences in the expression levels of HER2, ER, PR, TOPO II, EGFR, and Ki67 between pCR and non-pCR patients, underscoring their potential as predictive markers for NAC outcomes. Importantly, our results have shed light on the contentious issue surrounding TOPO II in NAC outcome prediction. We have provided evidence that establishes a significantly positive association between TOPO II expression level and the pCR rate. Notably, tumor size was identified as a relevant predictive factor for achieving pCR. Regarding biomarker profiles, only Ki67 levels and TOPO II status exhibited changes following NAC, resolving previous controversies. While the ER and PR status remained unchanged, their expression values exhibited a slight but significant decrease post-NAC. Our results provide clarity and insights into the value and potential of using these biomarkers to predict NAC responses and prognosis in breast cancer patients.

DNA Topoisomerase II-α Regulated by miR-22-5p Promotes Hepatocellular Carcinoma Invasion and Migration through the Hippo Pathway

DNA topoisomerases (TOPs) are dysregulated in various types of cancer. However, how TOP II-alpha (TOP2A) contributes to hepatocellular carcinoma (HCC) progression remains elusive. Cohort analysis revealed that the increased expression of TOP2A was associated with poor clinical outcomes and TOP2A was significantly upregulated in HCC tissues and cell lines. In vitro, TOP2A expression level is related to cell invasion and migration, which may be due to the alteration of epithelial-mesenchymal transition by the TOP2A. Moreover, we used verteporfin (a Hippo inhibitor) to test how the Hippo pathway promotes the effect of TOP2A on the HCC phenotype and found that TOP2A induces tumor progression through the Hippo pathway. Finally, miR-22-5p inhibited tumor progression by sponging TOP2A.

Identification of a novel catalytic inhibitor of topoisomerase II alpha that engages distinct mechanisms in p53wt or p53-/- cells to trigger G2/M arrest and senescence

We report a novel topoisomerase IIα inhibitor, mercaptopyridine oxide (MPO), which induces G2/M arrest and senescence with distinctly different cell cycle regulators (p21 or p14^ARF) in HCT116p 53^WT and HCT116 p53^-/- cells, respectively. MPO treatment induced defective topoisomerase IIα-mediated decatenation process and inhibition of the enzyme's catalytic activity that stalled entry into mitosis. Topoisomerase IIα inhibition was associated with ROS-mediated activation of ATM-Chk2 kinase axis in HCT116 p53^WT cells, but not in HCT116 p53^-/- cells displaying early Chk1 activation. Results suggest that E2F1 stabilization might link MPO-induced p53 phospho-activation in HCT116 p53^WT cells or p14^ARF induction in HCT116 p53^-/- cells. Also, interaction between topoisomerase IIα and Chk1 was induced in both cell lines, which could be important for decatenation checkpoint activation, even upon p53 ablation. Notably, TCGA dataset analyses revealed topoisomerase IIα upregulation across a wide array of cancers, which was associated with lower overall survival. Corroborating that increased topoisomerase IIα expression might offer susceptibility to the novel inhibitor, MPO (5 μM) induced strong inhibition in colony forming ability of pancreatic and hepatocellular cancer cell lines. These data highlight a novel topoisomerase IIα inhibitor and provide proof-of-concept for its therapeutic potential against cancers even with loss-of-function of p53.

The Significance of Topoisomerase II Alpha in Invasive Breast Carcinoma

Background

Topoisomerase II alpha (Top 2 A) protein has been shown to be a proliferation marker associated with tumour grade. The current study evaluated the prognostic impact of Top 2 A protein on luminal breast cancer and its utility as an independent prognostic marker. Immunohistochemical expression of Top 2 A in breast cancer and its correlation with the tumour type, size, lymph node metastases, grade and ER/PR positivity.

Methodology

Ethics committee approval was taken and 65 cases of Invasive breast carcinoma presenting to the Department of Pathology at a tertiary care centre in South India were studied. Patient details including age, tumour type, tumour size, tumour grading, estrogen receptor (ER)/progesterone receptor (PR)/human epidermal growth factor receptor 2 (HER2/neu) status and pathologic stage was studied. Immunohistochemistry (IHC) work-up for Top 2 A expression was done and evaluated.

Results

Of the 65 histological sections of breast cancers, 29/65 showed nuclear positivity for Top 2 A. Node positive tumours 17/65 stained positive for Top 2 A. Stage I tumours 2/65, stage II tumours 12/65 and stage III 14/65 stained positive for Top 2 A. Among the HER2/neu-positive tumours, 22/65 stained for Top 2 A and among ER/PR-positive 9/65 cases were positive for Top 2 A. Triple-negative tumours 5/65 stained for Top 2 A.

Conclusion

Higher Top 2 A expression was seen in higher stage tumours. HER2/neu-positive tumours significantly showed a correlation with Top 2 A positivity. Therefore, Top 2 A expression can be considered an individual prognostic factor in breast carcinoma.

A careful reassessment of anthracycline use in curable breast cancer

It has been over three decades since anthracyclines took their place as the standard chemotherapy backbone for breast cancer in the curative setting. Though the efficacy of anthracycline chemotherapy is not debatable, potentially life-threatening and long-term risks accompany this class of agents, leading some to question their widespread use, especially when newer agents with improved therapeutic indices have become available. Critically assessing when to incorporate an anthracycline is made more relevant in an era where molecular classification is enabling not only the development of biologically targeted therapeutics but also is improving the ability to better select those who would benefit from cytotoxic agents. This comprehensive analysis will present the problem of overtreatment in early-stage breast cancer, review evidence supporting the use of anthracyclines in the pre-taxane era, analyze comparative trials evaluating taxanes with or without anthracyclines in biologically unselected and selected patient populations, and explore published work aimed at defining anthracycline-sensitive tumor types.

Application of the 2013 ASCO/CAP guideline and the SISH technique for HER2 testing of breast cancer selects more patients for anti-HER2 treatment

The aim of this study is to assess the impact of changes of the 2013 ASCO/CAP guideline on the results of HER2 testing in breast cancer. A series of 916 primary invasive breast cancer cases, assessed as HER2 2+ by IHC in part using the 2007 and in part the 2013 ASCO/CAP criteria, was evaluated for HER2 amplification status by SISH and classified according to both 2007 and 2013 ASCO/CAP ISH guideline criteria. We observed a significant increase of HER2-positive cases (12.4 to 16.8%) and a decrease of HER2-equivocal cases (3.6 to 0.7%). Of the cases studied, 52.1% fulfilled both criteria of HER2/CEP17 ratio and average HER2 copy number per cell to be classified as HER2-positive. Reclassification of the cases from before the introduction of the new ASCO/CAP guideline with the 2013 ISH criteria resulted in an increase of cases with a HER2-positive status (12.4 to 14.2%) and in a decrease of HER2-equivocal cases (3.6 to 1.6%). The 2013 ASCO/CAP guideline selects more patients for anti-HER2 targeted therapy, mostly based on the modifications of criteria to evaluate ISH-HER2.

HER2 in situ hybridization in breast cancer: clinical implications of polysomy 17 and genetic heterogeneity

Trastuzumab-containing therapy is a standard of care for patients with HER2+ breast cancer. HER2 status is routinely assigned using in situ hybridization to assess HER2 gene amplification, but interpretation of in situ hybridization results may be challenging in tumors with chromosome 17 polysomy or intratumoral genetic heterogeneity. Apparent chromosome 17 polysomy, defined by increased chromosome enumeration probe 17 (CEP17) signal number, is a common genetic aberration in breast cancer and represents an alternative mechanism for increasing HER2 copy number. Some studies have linked elevated CEP17 count ('polysomy') with adverse clinicopathologic features and HER2 overexpression, although there are numerous discrepancies in the literature. There is evidence that elevated CEP17 ('polysomy') count might account for trastuzumab response in tumors with normal HER2:CEP17 ratios. Nonetheless, recent studies establish that apparent 'polysomy' (CEP17 increase) is usually related to focal pericentromeric gains rather than true polysomy. Assigning HER2 status may also be complex where multiple cell subclones with distinct HER2 amplification characteristics coexist within the same tumor. Such genetic heterogeneity affects up to 40% of breast cancers when assessed according to a College of American Pathologists guideline, although other definitions have been proposed. Recent data have associated heterogeneity with unfavorable clinicopathologic variables and poor prognosis. Genetically heterogeneous tumors harboring HER2-amplified subclones have the potential to benefit from trastuzumab, but this has yet to be evaluated in clinical studies. In this review, we discuss the implications of apparent polysomy 17 and genetic heterogeneity for assigning HER2 status in clinical practice. Among our recommendations, we support the use of mean HER2 copy number rather than HER2:CEP17 ratio to define HER2 positivity in cases where coamplification of the centromere might mask HER2 amplification. We also highlight a need to harmonize in situ hybridization scoring methodology to support accurate HER2 status determination, particularly where there is evidence of heterogeneity.

Correlations of TOP2A gene aberrations and expression of topoisomerase IIα protein and TOP2A mRNA expression in primary breast cancer: a retrospective study of 86 cases using fluorescence in situ hybridization and immunohistochemistry

Our aim in this study was to assess the status of TOP2A gene aberrations (no change/amplification or deletion) and its correlations with topoisomerase IIα (Topo IIα) protein and TOP2A mRNA expression, respectively. TOP2A amplification, Topo IIα protein expression and TOP2A mRNA expression were assessed using samples of 86 cases of breast cancer by fluorescence in fluorescence in situ hybridization, quantitative real-time polymerase chain reaction and immunohistochemistry, respectively. Twenty two (22.57%) had amplification/deletion of TOP2A gene. Twenty eight (32.56%) tumor samples were 17q polysomy or monosomy. Topo IIα protein was expressed in 57 cases (66.27%, 57/86): 22 cases (38.62%, 22/57) and 35 cases (61.40%, 35/57) had amplification/deletion and no change of TOP2A gene, respectively. These three groups showed significant differences by one-way analysis of variance (P < 0.001). The average Ct values of TOP2A mRNA expression in the tumors with deletion, amplification and no change of TOP2A gene were 27.00, 27.33 and 31.66, respectively. We demonstrated that the TOP2A gene was amplified or deleted in breast cancer, with a significant correlation with high expressions of Topo IIα protein and TOP2A mRNA expression. Ki-67 expression index (mean = 14.9) decreased significantly in cases wherein TOP2A gene had no change and Her2/neu protein expression was weakly positive (0-1+, P < 0.001).

The important molecular markers on chromosome 17 and their clinical impact in breast cancer

Abnormalities of chromosome 17 are important molecular genetic events in human breast cancers. Several famous oncogenes (HER2, TOP2A and TAU), tumor suppressor genes (p53, BRCA1 and HIC-1) or DNA double-strand break repair gene (RDM1) are located on chromosome 17. We searched the literature on HER2, TOP2A, TAU, RDM1, p53, BRCA1 and HIC-1 on the Pubmed database. The association of genes with chromosome 17, biological functions and potential significance are reviewed. In breast cancer, the polysomy 17 (three or more) is the predominant numerical aberration. HER2 amplification is widely utilized as molecular markers for trastuzumab target treatment. Amplified TOP2A, TAU and RDM1 genes are related to a significant response to anthracycline-based chemotherapy, taxane or cisplatin, respectively. In contrast, p53, BRCA1 and HIC-1 are important tumor suppressor genes related to breast carcinogenesis. This review focused on several crucial molecular markers residing on chromosome 17. The authors consider the somatic aberrations of chromosome 17 and associated genes in breast cancer.

Tumor topoisomerase II alpha status and response to anthracycline-based neoadjuvant chemotherapy in breast cancer

OBJECTIVES

Individualized chemotherapy for breast cancer improves the outcome. Anthracyclines target the enzyme topoisomerase IIα (TOP2A). We set out to perform a retrospective study of the presence of gene abnormalities and the expression of TOP2A in a cohort of breast cancer patients treated with neoadjuvant anthracycline-based chemotherapy.

METHODS

Forty-three patients with 45 breast cancers were treated with neoadjuvant docetaxel-epirubicin with/without capecitabine chemotherapy. The TOP2A status of the cancers, determined retrospectively by fluorescent in situ hybridization and immunohistochemistry, was analyzed in relation to the standard clinical and pathological data.

RESULTS

Clinically and pathologically complete remission (pCR) was achieved in 15 (33.3%) and 9 (20%) cases, respectively. The TOP2A gene was amplified in 2 human epidermal growth factor receptor 2 (HER2)-positive cancers (8%), and 32 (84.2%) overall exhibited TOP2A expression in >15% of the cells. The expression of TOP2A exhibited a strong correlation with the expression of Ki67 (R = 0.743, p < 0.001), and was negatively correlated with estrogen receptors (ER; R = 0.404, p = 0.012) and progesterone receptors (R = 0.430, p = 0.007). The expression of TOP2A was not related to the amplification of the TOP2A gene or the HER2 status of the tumor. The proportions of Ki67- and TOP2A-positive tumor cells were significantly reduced after chemotherapy (56.1 ± 23.6 vs. 19.0 ± 27.7%, p = 0.004, and 41.0 ± 27.9 vs. 12.7 ± 24.8%, p < 0.001, respectively). The development of pCR was related to a high grade (p = 0.054), ER negativity (p = 0.027) and high TOP2A expression (p = 0.037). The expression of TOP2A was an independent predictor of pCR (OR = 1.460, for every 10% increase, 95% CI: 1.016-2.096, p = 0.041). After a median follow-up time of 31.0 months, neither relapse-free survival nor overall survival was related to the tumor response.

CONCLUSIONS

TOP2A expression is a marker of the tumor's proliferation rate and sensitivity to anthracycline-based chemotherapy, and does not depend on the amplification of its gene.

Topoisomerase II alpha expression and the Ki-67 labeling index correlate with prognostic factors in estrogen receptor-positive and human epidermal growth factor type-2-negative breast cancer

BACKGROUND

Topoisomerase II alpha (Topo IIa) is involved in DNA replication and is a molecular target for anthracycline-based chemotherapy. The Ki-67 labeling index (LI) is an evaluation of tumor cell proliferation. The objective of this study was to evaluate relationships among Topo IIa expression, the Ki-67 LI, and prognostic factors in estrogen receptor (ER)-positive, human epidermal growth factor type-2 (HER2)-negative breast cancer.

MATERIALS AND METHODS

Seventy-one patients were diagnosed with ER-positive, HER2-negative breast cancer between July 2003 and December 2004. Formalin-fixed, paraffin-embedded tumor specimens were stained for Topo IIa expression and Ki-67 LI. We investigated the correlation of the level of Topo IIa expression and the Ki-67 LI with clinical factors such as age, tumor size, progesterone receptor status, nodal status, nuclear grade, and lymphovascular invasion (LVI).

RESULTS

Statistically significant differences were observed between Topo IIa overexpression, nuclear grade (p = 0.036), and LVI (p = 0.029). Topo IIa overexpression was statistically correlated with the Ki-67 LI (p < 0.0001). A statistically significant difference was observed between the Ki-67 LI and nuclear grade (p = 0.01). Survival analysis revealed the significant prognostic value of Ki-67 LI in patients with ER-positive, HER2-negative breast cancer (p = 0.003).

CONCLUSIONS

Ki-67 LI is a strong prognostic factor in ER-positive HER2-negative breast cancer. Topo IIa overexpression was significantly correlated with the Ki-67 LI, nuclear grade, and LVI. These findings suggest use of Topo IIa expression as a proliferation marker and a prognostic factor in ER-positive, HER2-negative breast cancer.

Topo2α protein expression predicts response to anthracycline combination neo-adjuvant chemotherapy in locally advanced primary breast cancer

Background:

This study aimed to identify predictors of response to anthracycline-based chemotherapy (5-fluoro-uracil, epirubicin, cyclophosphamide (FEC)) in locally advanced primary breast cancer (LAPC).

Methods:

A total of 91 LAPC patients were treated with six cycles of FEC before surgery. Protein expression of nine biomarkers (topoisomerase2α (Topo2α), ER, PR, HER2, Ki67, p53, EGFR, CK5/6 and CK14) was assessed in pre-chemotherapy core biopsies using immunohistochemistry (IHC) and results correlated with clinical and pathological response.

Results:

Clinical (cCR) and pathological (pCR) complete response were seen in 34.1% (n=31) and 20% (n=18), respectively. Pathological complete response was concordant with cCR in 14/31 cases; in four cases of cPR with palpable residual breast tumours, histology showed fibrous tissue only (pCR). On univariate analysis, pre-chemotherapy high expression of Topo2α protein (P=0.031), and negativity for ER and EGFR (P=0.001 and P=0.005, respectively) correlated with pCR. Positivity for p53 also showed significance (P=0.015), whereas basal phenotype, HER2, and all the clinicopathological variables of LAPC included in this study did not show significant correlation with response. On multivariate analysis, Topo2α expression had the strongest correlation with pCR (P=0.021) followed by EGFR (P=0.044).

Conclusion:

The study suggests that pre-chemotherapy Topo2α protein expression measured by IHC strongly correlates with pathological CR to neo-adjuvant anthracyclines in this group of LAPC studied.

ER, PgR, HER-2, Ki-67, topoisomerase IIα, and nm23-H1 proteins expression as predictors of pathological complete response to neoadjuvant chemotherapy for locally advanced breast cancer

The purpose of this study was to evaluate the importance of biological markers to predict pathologic complete response (pCR) to neoadjuvant chemotherapy (NCT) in patients with locally advanced breast cancer (LABC) One hundred and twelve consecutive patients with clinical stage III LABC who had received NCT with docetaxel and epirubicin from March 2006 to March 2009 were included in this retrospective study. The pre-NCT treatment expression levels of Ki-67 proliferation index, estrogen receptor (ER), progesterone receptor (PgR), epidermal growth factor receptor 2 (HER-2), Topoisomerase II alpha (Topo-II), and nm23-H1 were detected by immunohistochemistry (IHC). A total of 361 cycles were administered with the median number of three cycles per patient (range, 2-6). The pCR rate was 9.8% (95% CI, 4.3-15.3%). In univariate analysis, poor tumor differentiation, both negative of ER/PgR, negative Topo-II, and positive nm23-H1 were found to be significantly predictive of a pCR. ER/PgR status and nm23-H1 were significant for pCR on multivariate analysis (P = 0.006 and 0.025, respectively). ER/PgR status and nm23-H1 are independent predictive factors of pCR to neoadjuvant docetaxel plus epirubicin combination chemotherapy in patients with LABC.

Positive response to neoadjuvant cyclophosphamide and doxorubicin in topoisomerase II nonamplified/HER2/neu negative/polysomy 17 absent breast cancer patients

PURPOSE

Human epidermal growth factor receptor 2 (HER2)/neu, topoisomerase II alpha (TOP2A), and polysomy 17 may predict tumor responsiveness to doxorubicin (DOX) therapy.

METHODS

We identified neoadjuvant DOX/cyclophosphamide treated breast cancer patients in our registry from 1997 to 2008 with sufficient tissue for testing (n = 34). Fluorescence in situ hybridization (FISH) testing was done on deparaffinized tissue sections pretreated using vendor's standard protocol modification, and incubated with US Food and Drug Administration approved Abbott Diagnostics Vysis PathVysion™ probe set, including Spectrum-Green-conjugated probe to α-satellite DNA located at the centromere of chromosome 17 (17p11.1-q11.1) and a Spectrum-Orange-conjugated probe to the TOP2A gene. Morphometric analysis was performed using a MetaSystems image analysis system. Manual counting was performed on all samples in which autofluorescence and/or artifact prevented the counting of sufficient numbers of cells. A ratio >2.0 was considered positive for TOP2A amplification. Polysomy 17 (PS17) presence was defined as signals of ≥2.5. Outcomes were pathological complete response (pCR), partial response (PR), and nonresponse (NR).

RESULTS

Of 34 patients tested, one was TOP2A amplified (hormone receptor negative/HER2 negative, partial responder). The subset of TOP2A nonamplified, HER2 negative, and PS17 absent (n = 23) patients had treatment response: pCR = 2 (9%), PR = 14 (61%), and NR = 7 (30%). Including the two PS17 present and HER2-positive patients (n = 33), 76% of TOP2A nonamplified patients had pCR or PR.

CONCLUSIONS

We observed substantial treatment response in patients lacking three postulated predictors that would be difficult to attribute to cyclophosphamide alone. Patients who are HER2 negative and lack TOP2A amplification and PS17 should not be excluded from receiving DOX-containing regimens.

Topoisomerase II-α as a predictive factor of response to therapy with anthracyclines in locally advanced breast cancer

BACKGROUND

Topoisomerase II-α is a molecular target of anthracyclines; several studies have suggested that topoisomerase II-α expression is related to response to anthracycline treatment. The objective of this study was to evaluate if topoisomerase II-α overexpression predicts response to anthracycline treatment in locally advanced breast cancer patients.

MATERIAL AND METHODS

Topoisomerase II-α, HER2, estrogen receptor (ER) and progesterone receptor (PR) expression were evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded breast tumors from 111 patients presenting with locally advanced breast cancer between 1995 and 2002. The prognostic value of these markers was analyzed using a multivariate proportional hazards regression model and an interaction analysis between topoisomerase II-α status and dose intensity.

RESULTS

Tumors from 40 patients (36%) showed topoisomerase II-α overexpression, 62 patients (56%) for ER, 39 (35%) for PR and 26 (23%) for HER2. There were no significant correlations between topoisomerase II-α expression and response to therapy, progression-free survival (PFS) or overall survival (OS). Anthracycline dose intensity had a significant impact on PFS and OS in patients overexpressing topoisomerase II-α (P=0.010 and 0.027, respectively). Negative PR (P=0.041), positive HER2 (P=0.013) were identified as risk factors in the multivariate model. The multivariate analysis in patients topoisomerase II-α negative shown no significance (HR=0.92, IC 95% 0.39-2.15, P=0.839) while the multivariate analysis in topoisomerase II-α positive, dose intensity shown to be statistically significant (HR=2.725, IC 95% 1.07-6.95, P=0.036).

CONCLUSIONS

Our data do not support a correlation between topoisomerase II-α expression in breast cancer patients and improved clinical benefit with anthracycline therapy. However, they do suggest that tumors overexpressing topoisomerase II-α may experience better clinical benefit with higher anthracycline dose intensity.

Topoisomerase 2 alpha and the case for individualized breast cancer therapy

BACKGROUND

Many patients with breast cancer receive no benefit from their treatment. This has led to a search for novel therapeutic targets whose identification may facilitate a more tailored approach, thereby avoiding unnecessary toxicity. Of these, topoisomerase 2 alpha (TOP2A), located at the HER2/neu amplicon on chromosome 17, has generated particular interest because its expression has been shown to correlate with response to anthracycline-based therapies.

METHODS

We evaluated the relationship between TOP2A and its collocated gene, HER2/neu, and summarized the evidence for and against confining anthracycline-based therapies to those patients who demonstrate increased expression or amplification of these targets.

RESULTS

The emerging consensus supports the restriction of anthracyclines to those patients who are HER2/neu positive, with the evidence suggesting that alterations in the status of TOP2A are almost completely restricted to this group of patients.

CONCLUSIONS

It seems increasingly likely that response to anthracyclines is predicated on these alterations.

Predicting anthracycline benefit: have we made any progress?

PURPOSE OF REVIEW

The benefit from anthracycline-based vs. nonanthracycline-based adjuvant therapy is not experienced by all breast cancer patients. Identification of the individuals to derive this benefit may be guided by predictive biomarkers. This review focuses on the search for biomarkers, particularly focusing on the potential roles for HER-2 and/or topoisomerase IIalpha.

RECENT FINDINGS

Clarification of differential sensitivity to anthracyclines is complicated due to disease heterogeneity, complexity of underlying biological pathways, biomarker detection methods and features of study design. Meta-analyses suggest anthracycline benefit is restricted to patients with HER-2 amplified disease. However, diversity within HER-2 positive and HER-2 negative subgroups limits the use of HER-2 status as an independent marker. Certainly, subgroups within HER-2 negative disease have demonstrable incremental benefit from anthracycline-based therapy. Regarding topoisomerase IIalpha, the best method of detection and predictive role remain unclear.

SUMMARY

Although progress has been made in defining breast cancer subgroups and identifying patients with general chemosensitivity, we do not yet have reliable predictive markers for anthracyclines. With current evidence, neither HER-2 status nor topoisomerase IIalpha status can be considered clinically valuable in guiding prescription of anthracyclines. Disease heterogeneity may dictate prediction by tumour profiles, rather than any single marker. These profiles may incorporate a panel of markers, including not only tumour features, such as HER-2 and topoisomerase IIalpha, but also host-determined features, such as stroma and stroma-anthracycline interaction. A new generation of well powered clinical trials that attempt to incorporate breast cancer heterogeneity may bridge the gap between available results and individual patient care.

Topoisomerase IIalpha expression rather than gene amplification predicts responsiveness of adjuvant anthracycline-based chemotherapy in women with primary breast cancer

INTRODUCTION

Adjuvant anthracycline-based chemotherapy (AbCTX) is a standard treatment for patients with primary breast cancer. Its main target is topoisomerase IIalpha (TopIIa), a nuclear protein which is important for DNA replication and mitosis. We propose that the overexpression of the TopIIa protein or amplification of the TopIIa gene may be useful in predicting increased responsiveness towards AbCTX.

METHODS

Tumor tissues of 118 patients who received adjuvant AbCTX were examined by immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) for TopIIa and HER2. For IHC, the primary antibodies 485 (Dako) and NCL-TOPOIIA (Novocastra) were used. FISH analysis was performed with the SPEC HER2/CEP 17 Dual Color Probe (Zytovision) and LSI TOP 2A Spectrum Orange/CEP 17 Spectrum Green probe (Abbott). TopIIa IHC was evaluated by the immunoreactive score (IRS). FISH amplification was stated at an HER2-TopIIa/CEP 17 ratio > or = 2, deletion of TopIIa at a ratio <0.8.

RESULTS

The median age of the patient population was 50 years (range 23-77), 76 (64%) had tumors >2 cm in size, 98 (85%) were nodal positive, and 72 (66%) estrogen-receptor positive. Chemotherapy regimes consisted of epirubicin-cyclophosphamide (EC 40 pts), EC-CMF (18 pts), FAC/FEC (33 pts), anthracycline-taxane combinations (23 pts) and others (4 pts). After IHC, it was found that 19% of the tumors were positive for HER2 (3+) and the median IRS for TopIIa staining was 2 (49% positive); 28 (24%) tumors showed HER2 amplification, therefrom 20/22 (91%) within the HER2 3+ group. TopIIa gene was amplified in 17 cases (16%) and deletion was seen in 6 (5%) tumors. Of all cases with HER2 gene amplification, 14 (50%) cases of TopIIa co-amplification and one case of deletion were seen. Looking at histological parameters, TopIIa IHC correlated with nodal status (P = 0.018) and high grading (G3) (P = 0.047). After a median follow-up of 42 months (range 1-242), a significant prognostic factor for local recurrence was HER2 positivity (IHC P = 0.013 and FISH P = 0.023). Thirty-two patients developed metastasis (27%), which was correlated with HER2 FISH positivity (P = 0.024) and, as a trend, Top IIa IHC negativity (P = 0.094); 25 (21%) patients died from the disease. Negative prognostic parameters were the lack of estrogen-receptor expression (P = 0.008), lymphangiosis (P = 0.02), and TopIIa IHC negativity (P = 0.03).

CONCLUSION

In this cohort of patients, HER2 positivity indicated higher rates of local and distant recurrence. In contrast, TopIIa IHC positivity predicted lower risk of metastases and death, thus being a positive-predictive factor for the responsiveness to AbCTX. TopIIa gene amplification did not add predictive information. Therefore, we conclude that TopIIa protein expression might rather be the target of anthracyclines independent from gene copy number.

Impact of grade, hormone receptor, and HER-2 status in women with breast cancer on response to specific chemotherapeutic agents by in vitro adenosine triphosphate-based chemotherapy response assay

This study was designed to assess whether histological and biological factors of breast cancer can predict chemoresponse to specific agents. Adenosine triphosphate-based chemotherapy response assay (ATP-CRA) was employed to retrieve chemoresponse to 5-fluorouracil (5-FU), doxetaxel, doxorubicin, epirubicin, and paclitaxel in 49 patients. Tumors with high histologic and nuclear grade have higher response rate to doxorubicin (P<0.05) and palitaxel (P<0.05). Estrogen receptor (ER)-negative tumors respond well to doxorubicin (P=0.038), and progesterone receptor (PR)-negative tumors to 5-FU (P=0.039), doxetaxel (P=0.038), doxorubicin (P=0.000), epirubicin (P=0.010), and paclitaxel (P=0.003). Among the breast cancer subtypes determined by ER, PR, and HER-2 immunohistochemical stains, the HER-2+/ER- subtype has a higher response rate to doxorubicin (P=0.008). This in vitro result suggests that the combination of histologic and nuclear grade, hormone receptor, and HER-2 status can be a predictive factor of response to specific chemotherapy agents. Further in vivo study should be followed for clinical trials.

The role of topoisomerase IIalpha and HER-2 in predicting sensitivity to anthracyclines in breast cancer patients

Human epidermal growth factor receptor-2 (HER-2) and topoisomerase IIalpha (topo IIalpha) co-inhabit chromosome 17. In the search for predictive biomarkers to refine clinical prescription of cytotoxic agents, both HER-2 and topo IIalpha are under exploration for their potential role in identifying individuals with early breast cancer who may benefit from anthracycline therapy. Whilst recent meta-analyses support a predictive role for HER-2 amplification, it remains unclear whether HER-2 is the critical biomarker or whether it is a surrogate marker for topo IIalpha alteration, a known drug target of anthracyclines. The major limitation in considering HER-2 as a single marker is heterogeneity within the subgroups of HER-2 positive and HER-2 negative disease. For topo IIalpha, current data is inconclusive. Issues plaguing this field are technical variability in marker definition, complex regulation pathway of topo IIalpha and lack of prospective, adequately powered studies. With current evidence, neither HER-2 nor topo IIalpha gene status can be considered clinically valuable markers for anthracycline benefit. This paper will focus on issues relating to reliable detection and predictive analyses of HER-2 and topo IIalpha, and highlight potential developments in improving individualized approach to anthracycline use in early breast cancer patients.

Genetic characterization of breast cancer and implications for clinical management

Breast cancer is a genetic disease caused by the accumulation of mutations in neoplastic cells. In the last few years, high-throughput microarray-based molecular analysis has provided increasingly more coherent information about the genetic aberrations in breast cancer. New biomarkers and molecular techniques are slowly becoming part of the diagnostic and prognostic armamentarium available for pathologists and oncologists to tailor the therapy for breast cancer patients. In this review, we will focus on the contribution of breast cancer somatic genetics to our understanding of breast cancer biology and its impact on breast cancer patient management.

Evaluation of HER2 in breast cancer: reality and expectations

BACKGROUND

The introduction of drugs, whose mechanisms of action are directed against specific molecules involved in cancer initiation and/or progression, has changed the daily workup of breast cancer patients. At present, HER2 expression and/or amplification should be evaluated in every primary invasive breast cancer either at the time of diagnosis or at the time of recurrence, mostly to guide selection of trastuzumab in the adjuvant and/or metastatic setting. The adequate selection of patients is an essential step for indication of anti-HER2 therapy.

OBJECTIVE

This review focuses on the state of the art for HER2 evaluation in breast cancer, as well as expectations regarding future molecular assays based on mechanisms of resistance to HER2-driven therapy.

METHODS

Data were obtained by searching the PubMed database, including the terms 'HER2', 'in situ hybridisation', 'immunohistochemistry', 'trastuzumab', 'breast cancer', 'therapy', 'resistance' and 'tyrosine-kinase inhibitors', with a preference for updated publications.

CONCLUSION

Pathologists have a central role in the selection of patients who will benefit from anti-HER-based therapies, with a responsibility to obtain the most reliable results for immunohistochemistry and in situ hybridisation techniques. Pre-analytical variables, such as type of fixative and time of fixation, are critical to guarantee consistent and quality assays, as well as to facilitate interpretation and decrease interobserver variability. Rigorous quality control and centralisation of techniques/interpretation of results are recommended to guarantee consistent assays.

Predictive factors for anthracycline-based chemotherapy for human breast cancer

Predictive factors for anthracycline-based chemotherapy have yet to be incorporated into daily practice. Meta-analyses of studies using anthracycline-based treatment regimens have shown an improved prognosis for human epidermal growth factor receptor type 2 (HER2)-positive tumors, but not for HER2-negative tumors compared with results of non-anthracycline regimens. Currently it is believed that the positive association between HER2 status and anthracycline sensitivity is indirect, that is, their association may be mediated through topoisomerase II alpha (TOP2A), a target molecule of anthracyclines, since TOP2A is near HER-2 and co-amplification of the TOP2A gene frequently occurs in HER2-amplified tumors. This strongly suggests that TOP2A gene amplification is a predictive factor for anthracyline-based regimens. The Collaborative Study Group of Scientific Research of the Japanese Breast Cancer Society has demonstrated that TOP2A-positive and BRCA1-negative subsets evaluated by immunohistochemical staining show a significantly higher pathological complete response when treated with preoperative epirubicin-containing regimens. Combining these findings with the observation that triple-negative tumors and basal-like tumors respond to anthracycline treatment suggests that not only HER2-positive tumors but also a distinct subset of HER2-negative tumors may be sensitive to anthracycline-based regimens.