DNA topoisomerase IIalpha expression and the response toprimary chemotherapy in 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.

Topoisomerase IIα immunoexpression in feline mammary carcinomas: A correlation with Ki67 immunoexpression and the mitotic count

The aim of the study was to compare the immunohistochemical expression of topoisomerase IIα protein (Topo IIα) with Ki67 expression and mitotic count in feline mammary carcinomas (FMCs). Topo IIα is considered as a proliferation indicator as well as a molecular target of anthracycline chemotherapy. The studied material included 70 FMCs from female cats treated with mastectomy. Primary mouse monoclonal antibodies directed against Topo IIα and Ki67 were used in immunohistochemical reactions. The number of mitotic figures was counted at 400× magnification in a field of 2.37 mm2. Immunohistochemical reaction for Topo IIα occurred in cell nuclei. The Topo IIα index ranged from 6.12% to 54.60% and was positively correlated with the values of the Ki67 index (r = 0.7193) and the mitotic count (r = 0. 2858). This indicates the potential possibility of use of the immunohistochemical expression of Topo IIα to assess the rate of proliferation in FMCs. The wide range of expression of Topo IIα in individual tumorus found in the conducted studies allows us to hypothesize that its assessment could be used as a predictive marker in chemotherapy of FMCs with the use of anthracyclines. However, this requires confirmation in clinical trials.

Resistance to paclitaxel induces glycophenotype changes and mesenchymal-to-epithelial transition activation in the human prostate cancer cell line PC-3

The development of the multidrug resistance phenotype is one of the major challenges faced in the treatment of cancer. The multidrug resistance phenotype is characterized by cross-resistance to drugs with different chemical structures and mechanisms of action. In this work, we hypothesized that the acquisition of resistance in cancer is accompanied by activation of the epithelial-to-mesenchymal transition process, where the tumor cell acquires a more mobile and invasive phenotype; a fundamental step in tumor progression and in promoting the invasion of other organs and tissues. In addition, it is known that atypical glycosylations are characteristic of tumor cells, being used as biomarkers. We believe that the acquisition of the multidrug resistance phenotype and the activation of epithelial-to-mesenchymal transition provoke alterations in the cell glycophenotype, which can be used as glycomarkers for chemoresistance and epithelial-to-mesenchymal transition processes. Herein, we induced the multidrug resistance phenotype in the PC-3 human prostate adenocarcinoma line through the continuous treatment with the drug paclitaxel. Our results showed that the induced cell multidrug resistance phenotype (1) acquired a mixed profile between epithelial and mesenchymal phenotypes and (2) modified the glycophenotype, showing an increase in the level of sialylation and in the number of branched glycans. Both mechanisms are described as indicators of poor prognosis.

Oncofetal HMGA2 attenuates genotoxic damage induced by topoisomerase II target compounds through the regulation of local DNA topology

Rapidly dividing cells maintain chromatin supercoiling homeostasis via two specialized classes of enzymes, DNA topoisomerase type 1 and 2 (TOP1/2). Several important anticancer drugs perturb this homeostasis by targeting TOP1/2, thereby generating genotoxic DNA damage. Our recent studies indicated that the oncofetal chromatin structuring high‐mobility group AT‐hook 2 (HMGA2) protein plays an important role as a DNA replication fork chaperone in coping with DNA topological ramifications that occur during replication stress, both genomewide and at fragile sites such as subtelomeres. Intriguingly, a recent large‐scale clinical study identified HMGA2 expression as a sole predicting marker for relapse and poor clinical outcomes in 350 acute myeloid leukemia (AML) patients receiving combinatorial treatments that targeted TOP2 and replicative DNA synthesis. Here, we demonstrate that HMGA2 significantly enhanced the DNA supercoil relaxation activity of the drug target TOP2A and that this activator function is mechanistically linked to HMGA2's known ability to constrain DNA supercoils within highly compacted ternary complexes. Furthermore, we show that HMGA2 significantly reduced genotoxic DNA damage in each tested cancer cell model during treatment with the TOP2A poison etoposide or the catalytic TOP2A inhibitor merbarone. Taken together with the recent clinical data obtained with AML patients targeted with TOP2 poisons, our study suggests a novel mechanism of cancer chemoresistance toward combination therapies administering TOP2 poisons or inhibitors. We therefore strongly argue for the future implementation of trials of HMGA2 expression profiling to stratify patients before finalizing clinical treatment regimes.

Computational studies, design and synthesis of Pd(II)-based complexes: Allosteric inhibitors of the Human Topoisomerase-IIα

Herein, a robust docking protocol was developed by using a low-cost workflow to highlight the modulation at ATPase domain from Human Topoisomerase-IIα (TOP2A) towards four novel Pd(II)-complexes bearing N,S-donor ligands. In vitro TOP2A inhibition assay confirmed the ability of them to prevent the enzyme functions into concentration ranging at 6.25-25μM. These results exhibited more effectivity than anticancer agent etoposide (35μM) and merbarone (40-50μM). The compounds were screened via Resazurin assay against MCF-7, MDA-MB-231 (Human breast), DU-145 (Human prostate), A549 (Human lung) and Cal27 (Human tongue) tumor cell lines revealing great cytotoxic effects, primarily to MCF-7 (IC₅₀=1.81-4.46μM). As well, 1-4 exhibited their selectivity index (SI) higher than cisplatin against HEK-293 (human kidney) normal cells, at least 11.6-fold (SI_1-4=1.4-5.0; SI_cis=0.12). Further, Red Blood Cell hemolytic test suggested in vitro non-toxic character for compound 4, previously evaluated as the most effective TOP2A inhibitor.

Comparison of the effect of three different topoisomerase II inhibitors combined with cisplatin in human glioblastoma cells sensitized with double strand break repair inhibitors

Topoisomerase II (Topo2) inhibitors in combination with cisplatin represent a common treatment modality used for glioma patients. The main mechanism of their action involves induction of DNA double-strand breaks (DSBs). DSBs are repaired via the homology-dependent DNA repair (HRR) and non-homologous end-joining (NHEJ). Inhibition of the NHEJ or HRR pathway sensitizes cancer cells to the treatment. In this work, we investigated the effect of three Topo2 inhibitors-etoposide, NK314, or HU-331 in combination with cisplatin in the U-87 human glioblastoma cell line. Etoposide as well as NK314 inhibited Topo2 activity by stabilizing Topo2-DNA cleavable complexes whereas HU-331 inhibited the ATPase activity of Topo2 using a noncompetitive mechanism. To increase the effectiveness of the treatment, we combined cisplatin and Topo2 inhibitor treatment with DSB repair inhibitors (DRIs). The cells were sensitized with NHEJ inhibitor, NU7441, or the novel HRR inhibitor, YU238259, prior to drug treatment. All of the investigated Topo2 inhibitors in combination with cisplatin efficiently killed the U-87 cells. The most cytotoxic effect was observed for the cisplatin + HU331 treatment scheme and this effect was significantly increased when a DRI pretreatment was used; however, we did not observed DSBs. Therefore, the molecular mechanism of cytotoxicity caused by the cisplatin + HU331 treatment scheme is yet to be evaluated. We observed a concentration-dependent change in DSB levels and accumulation at the G2/M checkpoint and S-phase in glioma cells incubated with NK314/cisplatin and etoposide/cisplatin. In conclusion, in combination with cisplatin, HU331 is the most potent Topo2 inhibitor of human glioblastoma cells.

Association between Immunohistochemical Expression of Topoisomerase IIα, Her2 and Hormone Receptors and Response to Primary Chemotherapy in Breast Cancer

The aim of this study was to evaluate the association between immunohistochemical expression of topoisomerase IIα, HER2 and hormone receptors and response to primary anthracycline-based chemotherapy in locally advanced breast cancer. We analyzed 109 medical charts of patients treated with primary anthracycline-based chemotherapy in the Women's Integral Health Care Center from 1996 to 2004. The clinical and pathological response to primary chemotherapy was associated with topoisomerase IIα and HER2 expression and hormone receptor negativity. Statistical analysis was performed using chi-squared, Fisher's exact test and Mann-Whitney test. No statistical association between clinical response and expression of topoisomerase IIa, HER2 and hormone receptor negativity was found. However, there was an association between complete pathological response and hormone receptor negativity (P = 0.0289). The present study suggested that these markers should not be considered predictors of response to primary anthracycline-based chemotherapy, and prospective studies must be designed for this purpose.

Radiological and Pathological Predictors of Response to Neoadjuvant Chemotherapy in Breast Cancer: A Brief Literature Review

BACKGROUND

Early clinical response to neoadjuvant chemotherapy (NACT) in breast cancer correlates with pathological response at surgery. A tailored approach using biomarkers to predict response to NACT has become a research priority. Predictors of response can be divided into pathological and radiological biomarkers. Advances in gene expression profiling and diffusion-weighted MRI techniques are used to predict tumour response, and combinations thereof are the future of predicting response to NACT in early-stage breast cancer.

METHODS

We searched Medline, CINAHL and Embase databases for studies on NACT. Key words used were NACT, breast cancer, pathological* complete response, primary chemotherapy, radiological*, predictor*, gene expression and biomarkers limited to the English language. Pathological markers such as tumour subtypes, topoisomerase IIα expression, Ki67, apoptosis-related markers and gene expression profiling were included.

RESULTS

From 119 articles, 42 studies were reviewed; the majority of studies identified used pathological clinical response as an end point to NACT, whilst others used complete clinical response. Despite extensive studies, results regarding long-term survival following NACT and potential predictors are inconclusive.

CONCLUSION

Future development of a predictive model combining key pathological and radiological biomarkers could provide personalised treatment regimens that improve pathological complete response rates and longer-term outcomes.

Topoisomerase II alpha and TLE3 as predictive markers of response to anthracycline and taxane-containing regimens for neoadjuvant chemotherapy in breast cancer

Purpose

Anthracyclines and taxanes are considered the standard for neoadjuvant chemotherapy of breast cancer, although they are often associated with serious side effects and wide variability of individual response. In this study, we analyzed the value of topoisomerase II alpha (TOP2A) and transducin-like enhancer of split 3 (TLE3) as predictive markers of response to therapy with anthracyclines and taxanes.

Materials and methods

TOP2A and TLE3 protein expressions were evaluated using immunohistochemistry on 28 samples, obtained by core needle biopsy in patients with locally advanced breast carcinoma, subsequently subjected to epirubicin- and paclitaxel-based neoadjuvant chemotherapy. The immunohistochemical staining was correlated with the clinical response measured by the tumor size reduction evaluated by breast magnetic resonance imaging, prior and after chemotherapy, and by pathologic evaluation of the surgical specimen.

Results

Neoadjuvant chemotherapy achieved a size reduction in 26/28 tumors (92.9%), with an average percentage decrease of 45.6%. A downstaging was achieved in 71.4% of the cases of locally advanced carcinoma. TOP2A positivity was correlated with a greater reduction in tumor diameter (P=0.06); negative staining for TLE3 was predictive of a better response to neoadjuvant chemotherapy (P=0.07). A higher reduction in tumor diameter (P=0.03) was also found for tumors that were concurrently TLE3-negative and TOP2A-positive.

Conclusion

TOP2A and TLE3 showed a correlation with response to neoadjuvant chemotherapy. While TOP2A is a well-known marker of response to anthracyclines-based chemotherapy, TLE3 is a new putative predictor of response to taxanes. Data from the current study suggest that TOP2A and TLE3 warrant further investigation in a larger series as predictors of response to neoadjuvant chemotherapy for locally advanced breast carcinoma.

Expression of multidrug resistance proteins in invasive ductal carcinoma of the breast

Chemotherapy is commonly used for the treatment of breast cancer. However, the resistance to chemotherapeutic agents, often mediated by multidrug resistance (MDR) mechanisms, is a common occurrence. The present study examined the expression of several MDR-related proteins (MRPs) in invasive ductal carcinoma (IDC) of the breast, and assessed their association with clinicopathological variables and their prognostic significance. In addition, immunohistochemistry was used to measure the expression of MRP, p-glycoprotein (P-gp), topoisomerase 2α (Topo2α), thymidylate synthase (TS) and glutathione-S-transferase π (GST-π) in 156 resected IDCs of the breast. Pearson's χ² test and Spearman's correlation coefficient were used to analyze the association between MDR protein expression and several clinicopathological variables. The association between each of the five MDR proteins was also examined. Furthermore, Kaplan-Meier analysis and Cox regression modeling were used to assess overall survival. The expression of MRP, P-gp, Topo2α, TS and GST-π was detected in 20.5% (32/156), 25.0% (39/156), 84.0% (131/156), 41.7% (65/156) and 41.0% (64/156) of cases examined, respectively. No correlation was identified between MRP and Topo-2α and the clinicopathological variables examined. By contrast, P-gp (χ²=20.226; P<0.0001) and GST-π (χ²=35.032; P<0.0001) were found to positively correlate with tumor grade. In addition, staining for TS was associated with axillary lymph node metastasis (χ²=42.281; P<0.0001). The expression levels of P-gp and GST-π were found to be significantly correlated (r= 0.319; P<0.0001). Furthermore, GST-π expression was elevated in estrogen receptor-negative breast cancer (χ²=17.407; P<0.0001). Tumor histological grade, in addition to TS and GST-π expression, were significant predictors of a poor survival outcome. TS and GST-π are consequently useful prognostic biomarkers in IDC, therefore, when establishing a personalized chemotherapeutic plan, the expression of MDR proteins must be considered.

Cytotoxic activity of octahydropyrazin[2,1-a:5,4-a']diisoquinoline derivatives in human breast cancer cells

Evaluation of the cytotoxicity of novel octahydropyrazin[2,1-a:5,4-a']diisoquinoline derivatives (1a-2c) employing a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and inhibition of [(3)H]thymidine incorporation into DNA demonstrated that these compounds were more active than etoposide and camptothecin in both MDA-MB-231 and MCF-7 human breast cancer cells. Flow cytometric analysis after Annexin V-FITC and propidium iodide staining also confirmed that apoptosis was the main response of human breast cancer cells to 1a-2c treatment. Our results suggest that apoptosis of human breast cancer cells in the presence of 1a-2c follows the mitochondrial pathway, with the decrease in mitochondrial membrane potential and activation of caspase 9, as well as by the external pathway with the significant increase in caspase 8 expression. Cytotoxic properties of compounds 1a-2c in cultured human breast cancer cells correlate to their ability to inhibit topoisomerase I/II.

Topoisomerase II-alfa gene as a predictive marker of response to anthracyclines in breast cancer

Amplification or deletion of the topoisomerase IIα (TOP2A) gene in breast cancer has been related with responsiveness to anthracyclines-based chemotherapy. The purpose of this study was to evaluate the predictive value of TOP2A gene for the efficacy of neo-adjuvant anthracycline in a population with locally advanced breast cancer. Sixty-two patients were included, and the status of TOP2A gene was determined by in situ hybridization method. Treatment efficacy was determined by clinical and pathological response and overall survival. TOP2A gene alterations were found in 22.6% (21.0% of cases with amplification and 1.6% with deletion), and these tumors were biologically more aggressive, with higher nuclear grade, more frequently with HER2 amplification and inflammatory type. Also in these tumors response to chemotherapy appeared to be increased. There was a higher clinical and pathological response rate (complete pathological response of 21.4% vs. 8.3%), a trend toward longer progression-free survival (82.51 vs. 63.12 months) and a trend to increased overall survival (92.08 months; 95% CI 82.81-101.35 vs. 73.40 months; 95% CI 63.44-83.36; p=0.113). These results corroborate that the TOP2A gene alterations may play an important role in determining anthracycline sensitivity in breast cancer.

Biomarkers for the clinical management of breast cancer: international perspective

The higher incidence of breast cancer in developed countries has been tempered by reductions in mortality, largely attributable to mammographic screening programmes and advances in adjuvant therapy. Optimal systemic management requires consideration of clinical, pathological and biological parameters. Oestrogen receptor alpha (ERα), progesterone receptor (PgR) and human epidermal growth factor receptor 2 (HER2) are established biomarkers evaluated at diagnosis, which identify cardinal subtypes of breast cancer. Their prognostic and predictive utility effectively guides systemic treatment with endocrine, anti-HER2 and chemotherapy. Hence, accurate and reliable determination remains of paramount importance. However, the goals of personalized medicine and targeted therapies demand further information regarding residual risk and potential benefit of additional treatments in specific circumstances. The need for biomarkers which are fit for purpose, and the demands placed upon them, is therefore expected to increase. Technological advances, in particular high-throughput global gene expression profiling, have generated multi-gene signatures providing further prognostic and predictive information. The rational integration of routinely evaluated clinico-pathological parameters with key indicators of biological activity, such as proliferation markers, also provides a ready opportunity to improve the information available to guide systemic therapy decisions. The additional value of such information and its proper place in patient management is currently under evaluation in prospective clinical trials. Expanding the utility of biomarkers to lower resource settings requires an emphasis on cost effectiveness, quality assurance and possible international variations in tumor biology; the potential for improved clinical outcomes should be justified against logistical and economic considerations.

Phosphorylation and stabilization of topoisomerase IIα protein by p38γ mitogen-activated protein kinase sensitize breast cancer cells to its poisons

Cancer drugs suppress tumor cell growth by inhibiting specific cellular targets. However, most drugs also activate several cellular nonspecific stress pathways, and the implications of these off-target effects are mostly unknown. Here, we report that p38γ, but not p38α, MAPK is specifically activated by treatment of breast cancer cells with topoisomerase II (Topo II) drugs, whereas paclitaxel (Taxol) does not have this effect. The activated p38γ in turn phosphorylates and stabilizes Topo IIα protein, and this enhances the growth inhibition by Topo II drugs. Moreover, p38γ activity was shown to be necessary and sufficient for Topo IIα expression, the drug-p38γ-Topo IIα axis is only detected in intrinsically sensitive but not resistant cells, and p38γ is co-overexpressed with Topo IIα protein in primary breast cancers. These results reveal a new paradigm in which p38γ actively regulates the drug-Topo IIα signal transduction, and this may be exploited to increase the therapeutic activity of Topo II drugs.

The role of topoisomerase IIα in predicting sensitivity to anthracyclines in breast cancer patients: a meta-analysis of published literatures

Topoisomerase IIα is not only a proliferation marker of tumor cells, but is also a target for anthracycline-based chemotherapy. Both in vitro and in vivo studies have shown that there is a relationship between topo IIα and chemosensitivity to anthracyclines, but the predictive role of topo IIα in breast cancer patients is still controversial. A meta-analysis based on published studies was performed to obtain an accurate assessment of the association between topo IIα and sensitivity to anthracycline-based chemotherapy. A total of 13 eligible studies, including 2,633 cases and 2,118 controls were identified. Topo IIα was associated with sensitivity to anthracyclines in locally advanced breast cancer patients who received neoadjuvant chemotherapy [five studies, including three using fluorescence in situ hybridization (FISH) and two using immunohistochemistry (IHC): relative risk (RR) = 1.93, 95% confidence interval (95% CI): 1.27-2.94, P = 0.002; two using FISH and three using IHC: RR = 1.98, 95% CI: 1.37-2.86, P < 0.001]. This association existed among three studies using FISH (RR = 2.03, 95% CI: 1.14-3.61, P = 0.017), but did not exist among three studies using IHC (P > 0.05). In early-stage breast cancer patients who received anthracycline-based adjuvant chemotherapy compared with non-taxane-based polychemotherapy, amplification [hazard ratio (HR) = 0.64, 95% CI: 0.49-0.83, P = 0.001; HR = 0.59, 95% CI: 0.35-1.01, P = 0.056] or deletion (HR = 0.82, 95% CI: 0.67-1.00, P = 0.051; HR = 0.58, 95% CI: 0.35-0.97, P = 0.036) of topo IIα was significantly associated with better recurrence-free survival and overall survival. In summary, the present meta-analysis suggests that topo IIα is a predictive factor for breast cancer patients who receive anthracycline-based chemotherapy. Larger and well-designed prospective studies are required to further evaluate the predictive role of topo IIα in clinical practice.

Topoisomerase II alpha protein and responsiveness of breast cancer to adjuvant chemotherapy with CEF compared to CMF in the NCIC CTG randomized MA.5 adjuvant trial

Overexpression of topoisomerase II protein (topo 2α) is postulated to be more closely associated with responsiveness to anthracycline-containing chemotherapy than human epidermal growth factor receptor type 2 (HER2) gene amplification or alterations in the topoisomerase II alpha gene (TOP2A). The authors used tissue microarrays from 477 of 710 premenopausal women with node-positive breast cancer randomized to CEF or CMF adjuvant chemotherapy in the NCIC Clinical Trials Group Mammary 5 (MA.5) trial. No significant interaction was found between treatment and continuous topo 2α level in either relapse-free (RFS) or overall survival (OS). In 136 patients (28.5%) whose tumors showed topo 2α overexpression by immunohistochemistry based on a cut-off of 13%, CEF was superior to CMF for RFS (adjusted HR 0.45; 95% CI 0.25-0.82; P = 0.009) and OS (adjusted HR 0.50; 95% CI 0.26-0.96; P = 0.04). When tumors lacked topo 2α overexpression, CEF was not superior for RFS (adjusted HR 0.88; 95% CI 0.64-1.22; P = 0.46) or OS (adjusted HR 0.95; 95% CI 0.66-1.38; P = 0.80). Interaction between topo 2α and treatment was borderline significant for RFS (P = 0.04) and OS (P = 0.05) and not substantially more significant than between TOP2A gene alteration (P (interaction) = 0.09 for RFS and 0.02 for OS) or HER2 overexpression (P (interaction) = 0.002 for RFS and 0.009 for OS). Topo 2α protein overexpression based on the cut-off identified in this study, TOP2A gene alterations and HER2 protein overexpression were each associated with responsiveness to anthracycline-containing chemotherapy. The topo 2α protein analysis was exploratory and will require further validation.

Multifactorial approach to predicting resistance to anthracyclines

PURPOSE

Validated biomarkers predictive of response/resistance to anthracyclines in breast cancer are currently lacking. The neoadjuvant Trial of Principle (TOP) study, in which patients with estrogen receptor (ER) -negative tumors were treated with anthracycline (epirubicin) monotherapy, was specifically designed to evaluate the predictive value of topoisomerase II-α (TOP2A) and develop a gene expression signature to identify those patients who do not benefit from anthracyclines.

PATIENTS AND METHODS

The TOP trial included 149 patients, 139 of whom were evaluable for response prediction analyses. The primary end point was pathologic complete response (pCR). TOP2A and gene expression profiles were evaluated using pre-epirubicin biopsies. Gene expression data from ER-negative samples of the EORTC (European Organisation for Research and Treatment of Cancer) 10994/BIG (Breast International Group) 00-01 and MDACC (MD Anderson Cancer Center) 2003-0321 neoadjuvant trials were used for validation purposes.

RESULTS

A pCR was obtained in 14% of the evaluable patients in the TOP trial. TOP2A amplification, but not protein overexpression, was significantly associated with pCR (P ≤ .001 v P ≤ .33). We developed an anthracycline-based score (A-Score) combining three signatures: a TOP2A gene signature and two previously published signatures related to tumor invasion and immune response. The A-Score was characterized by a high negative predictive value ([NPV]; NPV, 0.98; 95% CI, 0.90 to 1.00) overall and in the human epidermal growth factor receptor 2 (HER2) -negative and HER2-positive subpopulations. Its performance was independently confirmed in the anthracycline-based arms of the two validation trials (BIG 00-01: NPV, 0.83; 95% CI, 0.64 to 0.94 and MDACC 2003-0321: NPV, 1.00; 95% CI, 0.80 to 1.00).

CONCLUSION

Given its high NPV, the A-Score could become, if further validated, a useful clinical tool to identify those patients who do not benefit from anthracyclines and could therefore be spared the non-negligible adverse effects.

Pathological tumor response to neoadjuvant chemotherapy using anthracycline and taxanes in patients with triple-negative breast cancer

Although triple-negative breast cancer (TNBC) is associated with a poor prognosis, recent reports have indicated that a higher proportion of TNBC patients shows a pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) than is the case for non-TNBC patients. The aim of this study was to identify markers that predict pCR to NAC in TNBC patients, and to clarify prognostic factors that affect the outcome of TNBC patients with residual disease (RD) after NAC. Among 44 TNBC patients who received anthracycline- and taxane-based combination NAC, we analyzed the relationship between pathological response and clinicopathological characteristics, including immunohistochemical parameters (cytokeratin 5/6, epidermal growth factor receptor, Ki-67, p53, breast cancer susceptibility protein 1 and topoisomerase IIα). We also assessed the prognostic impact on patients with RD by analyzing the correlation between disease-free survival (DFS) and clinicopathological parameters. Sixteen patients (36%) achieved a pCR and log-rank test showed that these patients had a significantly more favorable outcome than patients with RD (DFS, P=0.00184; overall survival, P=0.0080). Among the clinicopathological parameters examined, none was correlated with pathological response, with the exception of p53. Patients with immunohistochemical overexpression of p53 more frequently achieved a pCR than those without p53 overexpression (P=0.0484). In the patients with RD, the Cox proportional hazards model showed that the presence of lymphovascular invasion was significantly associated with shorter DFS (hazard ratio, 13.333; 95% CI 1.587-111.111; P=0.0171). p53 overexpression may be a key predictor of a favorable response to NAC. Since patients with RD, particularly those positive for lymphovascular invasion, had an extremely poor outcome, novel therapeutic approaches for these patients are warranted.

Significance of topoisomerase IIIβ expression in breast ductal carcinomas: strong associations with disease-specific survival and metastasis

Topoisomerases are ubiquitous nuclear enzymes that regulate DNA structure in eukaryotic cells. The role of topoisomerase IIIβ, the newest member of the topoisomerase family, in the clinical outcome of breast cancer is still poorly understood. This study aims to investigate the immunoexpression of topoisomerase IIIβ in breast cancer and its relationships with clinicopathologic features and immunohistochemical markers of prognostic significance in breast pathology. Using tissue microarrays containing 171 cases of primary invasive breast cancer, we analyzed the immunoexpression of topoisomerase IIIβ, estrogen receptor, progesterone receptor, HER-2, BRCA-1, p53, and Ki67. Immunostaining for topoisomerase IIIβ was found in 33.9% of breast carcinomas, and immunopositivity was correlated with distant metastasis (P = .036) and death (P = .006). Decreased expression of topoisomerase IIIβ correlated with low expression of Ki67 (P < .001) and negativity for HER-2 (P < .001), BRCA-1 (P = .001), and p53 (P < .001). In the multivariate analysis, topoisomerase IIIβ expression was a significant predictor of survival (hazard ratio, 3.006 [95% confidence interval, 1.582-5.715]; P = .001). In conclusion, topoisomerase IIIβ expression can be a useful marker in assessing the prognosis of patients with breast cancer and is an independent predictor of survival.

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.

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.

The topoisomerase II alpha gene status in primary breast cancer is a predictive marker of the response to anthracycline-based neoadjuvant chemotherapy

This study aimed at evaluating the usefulness of topoisomerase II alpha (TOP2A) for predicting the effect of anthracycline-based neoadjuvant chemotherapy in breast cancer. The TOP2A status was examined using fluorescent in situ hybridization (FISH) in 14 pre-chemotherapeutic breast cancer tissues, and was also assessed by immunohistochemistry (IHC) in 14 pairs of pre- and post-chemotherapeutic breast cancer specimens. TOP2A gene aberration by IHC tended to show a correlation with pathological responses but this was not statistically significant (p=0.060). On the other hand, the low TOP2A/CEP17 ratio correlated with good pathological responses (p=0.012). TOP2A overexpression was not significantly associated with response (p=0.580). Our results thus suggest that the TOP2A/CEP17 ratio may be a useful predictor of the effects of anthracycline-based neoadjuvant chemotherapy in breast cancer.

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.

The potential biomarkers in predicting pathologic response of breast cancer to three different chemotherapy regimens: a case control study

Background

Preoperative chemotherapy (PCT) has become the standard of care in locally advanced breast cancer. The identification of patient-specific tumor characteristics that can improve the ability to predict response to therapy would help optimize treatment, improve treatment outcomes, and avoid unnecessary exposure to potential toxicities. This study is to determine whether selected biomarkers could predict pathologic response (PR) of breast tumors to three different PCT regimens, and to identify a subset of patients who would benefit from a given type of treatment.

Methods

118 patients with primary breast tumor were identified and three PCT regimens including DEC (docetaxel+epirubicin+cyclophosphamide), VFC (vinorelbine/vincristine+5-fluorouracil+cyclophosphamide) and EFC (epirubicin+5-fluorouracil+cyclophosphamide) were investigated. Expression of steroid receptors, HER2, P-gp, MRP, GST-pi and Topo-II was evaluated by immunohistochemical scoring on tumor tissues obtained before and after PCT. The PR of breast carcinoma was graded according to Sataloff's classification. Chi square test, logistic regression and Cochran-Mantel-Haenszel assay were performed to determine the association between biomarkers and PR, as well as the effectiveness of each regimen on induction of PR.

Results

There was a clear-cut correlation between the expression of ER and decreased PR to PCT in all three different regimens (p < 0.05). HER2 expression is significantly associated with increased PR in DEC regimen (p < 0.05), but not predictive for PR in EFC and VFC groups. No significant correlation was found between biomarkers PgR, Topo-II, P-gp, MRP or GST-pi and PR to any tested PCT regimen. After adjusted by a stratification variable of ER or HER2, DEC regimen was more effective in inducing PR in comparison with VFC and EFC regimens.

Conclusion

ER is an independent predictive factor for PR to PCT regimens including DEC, VFC and EFC in primary breast tumors, while HER2 is only predictive for DEC regimen. Expression of PgR, Topo-II, P-gp, MRP and GST-pi are not predictive for PR to any PCT regimens investigated. Results obtained in this clinical study may be helpful for the selection of appropriate treatments for breast cancer patients.

A literature review of molecular markers predictive of clinical response to cytotoxic chemotherapy in patients with breast cancer

BACKGROUND

We aimed to identify, through a review of the literature, candidate genes for a prospective predictive chemosensitivity test in patients with breast cancer.

METHODS

Papers demonstrating an association between gene alterations in tumor tissue and clinical chemosensitivity in breast cancer patients were selected by Medline searches. We calculated odds ratios (ORs) and their 95% confidence intervals (CIs) of response rates for patients who had tumors with or without gene alteration. Combined ORs and CIs were estimated using the DerSimonian-Laird method.

RESULTS

A total of 18 genes were evaluated for association with clinical chemosensitivity in 6378 patients registered in 69 studies. The median (range) number of patients in each study was 73 (29-319). Overexpression of ABCB1 (P-glycoprotein) was associated with poor responses to first-line chemotherapy (combined OR [CI], 0.16 [0.05-0.59]; n = 322). Overexpression and amplification of TOP2A (topoisomerase II-alfa) were more frequently observed in patients who responded to first-line chemotherapy (combined OR [CI], 2.73 [1.02-7.27]; n = 323). Overexpression of ERBB2 (c-erbB2) was associated with favorable responses in patients treated with both first-line anthracycline-based chemotherapy and second-line taxane-based chemotherapy (combined ORs [CIs], 1.60 [1.19-2.17]; n = 1807 and 2.24 [1.06-4.74]; n = 259, respectively). BCL2 overexpression was associated with resistance to first-line chemotherapy (combined OR [CI], 0.44 [0.21-0.91]; n = 816).

CONCLUSION

ABCB1, TOP2A, ERBB2, and BCL2 were good candidates for future clinical trials of predictive chemosensitivity tests in patients with breast cancer.

Emerging biomarkers and new understanding of traditional markers in personalized therapy for breast cancer

The era of personalized medicine is likely to see an escalation in the use of biomarkers to ensure breast cancer patients receive optimal treatment. A combination of prognostic and predictive biomarkers should enable better quantification of the residual risk faced by patients and indicate the potential value of additional treatment. Established biomarkers such as estrogen receptor and progesterone receptor already play a significant role in the selection of patients for endocrine therapy. Human epidermal growth factor receptor 2 (HER2) is recognized as a strong predictor of response to trastuzumab whereas, more recently, the role of estrogen receptor and HER2 as negative and positive indicators for chemotherapy has also been explored. Ki67 has traditionally been recognized as a modest prognostic factor, but recent neoadjuvant studies suggest that on-treatment measurement may be a more effective predictor of treatment efficacy for both endocrine treatment and chemotherapy. The last decade has seen the emergence of numerous multigene expression profiles that aim to outdo traditional predictive and prognostic factors. The Oncotype DX assay and the MammaPrint profile are currently undergoing prospective clinical trials to clearly define their role. Other gene expression-based assays also show potential but are yet to be tested clinically. Rigorous comparison of these emerging markers with current treatment selection criteria will be required to determine whether they offer significant benefit to justify their use.

Topoisomerase II alpha gene copy loss has adverse prognostic significance in ERBB2-amplified breast cancer: a retrospective study of paraffin-embedded tumor specimens and medical charts

BACKGROUND

Amplification of the ERBB2 (Her-2/neu) oncogene, which occurs in approximately 25% of breast carcinomas, is a known negative prognostic factor. Available data indicate that a variable number of nearby genes on chromosome 17q may be co-amplified or deleted, forming a continuous amplicon of variable size. In approximately 25% of these patients, the amplicon extends to the gene for topoisomerase II alpha (TOP2A), a target for anthracyclines. We sought to understand the significance of these associated genomic changes for breast cancer prognosis and predicting response to therapy.

METHODS AND PATIENTS

Archival tissue samples from 63 breast cancer patients with ERBB2 amplification, stages 0-IV, were previously analyzed with FISH probes for genes located near ERBB2. In the present study, the clinical outcome data were determined for all patients presenting at stages I-III for whom adequate clinical follow up was available.

RESULTS

Four amplicon patterns (Classes) were identified. These were significantly associated with the clinical outcome, specifically, recurrence of breast cancer. The Amplicon class IV with deleted TOP2A had 67% (6/9) cases with recurrence, whereas the other three classes combined had only 12% (3/25) cases (p-value = 0.004) at the time of last follow-up. TOP2A deletion was also significantly associated with time to recurrence (p-value = 0.0002). After adjusting for age in Cox regression analysis, the association between TOP2A deletion and time to recurrence remains strongly significant (p-value = 0.002) whereas the association with survival is marginally significant (p-value = 0.06).

CONCLUSION

TOP2A deletion is associated with poor prognosis in ERBB2-amplified breast carcinomas. Clarification of the mechanism of this association will require additional study.

Topoisomerase IIalpha expression as an independent prognostic factor in Hodgkin's lymphoma

PURPOSE

To correlate the immunohistochemical expression of topoisomerase IIalpha (topoIIalpha) in Hodgkin's lymphoma (HL) with clinicopathological parameters, the expression of Ki-67 and the outcome of patients, who had been homogenously treated with ABVD or equivalent regimens.

EXPERIMENTAL DESIGN

Immunohistochemistry using the monoclonal antibody Ki-S1 (topoIIalpha) was performed in 238 HL patients. MiB1 (Ki-67) expression was evaluated in 211/238.

RESULTS

The mean +/- SD percentage of topoIIalpha- and Ki-67-positive Hodgkin-Reed-Sternberg (HRS) cells was 63 +/- 19% (5%-98%) and 73 +/- 19% (8%-99%), respectively. The median percentage of topoIIalpha-positive HRS cells was 64% (interquartile range, 51-78%). There was no correlation between topoIIalpha expression and patient characteristics. TopoIIalpha and Ki-67 expression were correlated (Spearman's Rho 0.255, P < 0.001). TopoIlalpha expression within the highest quartile of this patient population was predictive of failure free survival (FFS) (10-year rates 82 +/- 3% vs 68 +/- 7%, P = 0.02 for patients falling into the quartiles 1-3 and 4 respectively). In multivariate analysis topoIIalpha expression was independently predictive of FFS.

CONCLUSION

TopoIIalpha was expressed in all cases of HL showing a correlation with Ki-67 expression. Under current standard therapy including drugs inhibiting its activity, topoIIalpha was an independent adverse predictor of FFS with no statistically significant correlation with other established prognostic factors.

Chemotherapy for Early-Stage Breast Cancer: A Paradigm in Flux

Breast cancer is the most common malignancy among women in the United States. A reduction in breast cancer mortality has been observed over recent years and is in part attributable to general use of adjuvant chemotherapy and trastuzumab. Besides the addition of specific therapeutic agents, the therapy of early-stage breast cancer has benefited from dose-dense approaches, identification of molecular markers, and translational research innovations such as prognostic gene expression assays. Treatment recommendations for adjuvant breast cancer chemotherapy are traditionally guided by results from clinical studies reflecting a general population; however, molecular and genomic information can potentially enable clinicians to formulate more refined therapeutic decisions. These advances also generate further questions regarding situations where application of therapy is necessary to optimize efficacy and circumstances where sparing therapy is appropriate. Taken together, the advances made through early-stage breast cancer chemotherapy positions us closer to fulfilling the promise of personalized medicine. This article reviews the recent progress of adjuvant chemotherapy and trastuzumab in breast cancer.

Upregulation of topoisomerase IIalpha expression in advanced gallbladder carcinoma: a potential chemotherapeutic target

PURPOSE

The lack of treatment options other than surgical resection results in unfavourable prognosis of advanced gallbladder carcinoma. The aim of this study was to identify cancer-specific cellular targets that would form the basis for some therapeutic approaches for this disease.

METHODS

Twelve advanced gallbladder carcinoma tissue samples and three samples of normal gallbladder epithelium were screened to identify differentially expressed genes by DNA microarray analysis. The results obtained were validated in an independent sample set by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). Among the genes picked-up, one molecule, topoisomerase IIalpha (TOPO IIalpha), was further assessed immunohistochemically as a potential chemotherapeutic target, and the growth inhibitory effects of etoposide, doxorubicin and idarubicin, representative TOPO IIalpha inhibitors, on two different gallbladder carcinoma cell lines were compared with that of gemcitabine and 5-fulorouracil.

RESULTS

Five upregulated genes were identified: four cell cycle-related genes (TOPO IIalpha, cyclin B2, CDC28 protein kinase regulatory subunit 2, ubiquitin-conjugating enzyme E2C) and a metabolism-related gene (gamma-glutamyl hydrolase). Immunohistochemically, TOPO IIalpha was expressed in gallbladder cancer cells, and 16 of 35 cases (46%) had strong TOPO IIalpha expression defined as having a labeling index of >50%. In in vitro growth inhibition assay, etoposide, as well as doxorubicin and idarubicin, was the most effective for OCUG-1 cells that had strong TOPO IIalpha expression, while gemicitabine was the most effective for NOZ cells with weak TOPO IIalpha expression. Etoposide induced apoptosis of OCUG-1 cells.

CONCLUSIONS

TOPO IIalpha might be an effective chemotherapeutic target in advanced gallbladder carcinoma, especially when it is expressed strongly.

HER-2, TOP2A and chromosome 17 alterations in breast cancer

HER-2 amplification is a biomarker for identifying patients who respond to trastuzumab and has been evaluated as a factor predicting the response to anthracyclines. The relationship between HER-2 and response to anthracycline therapy may also be the result of the close localization of TOP2A on 17q. It has been a matter of debate whether these two genes, HER-2 and TOP2A, behave separately on different amplicons or act together thus making it possible to predict the TOP2A status from the HER-2 status. In this study TOP2A, HER-2 and chromosome 17 aneusomy were investigated by fluorescent in situ hybridization (FISH) in 50 consecutive breast cancer patients. HER-2 amplification was detected in 11 patients (22%) and TOP2A changes were seen in 6 patients (12%); two amplifications and two deletions were observed in HER-2-amplified cases and two deletions in HER-2-nonamplified cases. Three of the TOP2A-deleted cases had polysomy 17. HER-2 copy number was higher than the TOP2A copy number in one patient with co-amplification. Polysomy was observed in 9 cases (18%) and monosomy in 6 cases (12%). Aneusomy was the sole anomaly in 11 patients (22%). We conclude that the TOP2A status cannot be predicted from the HER-2 status and evaluation of the TOP2A status only in patients with HER-2 overexpression may lead to missing cases with TOP2A deletion with possible resistance to therapy. Other factors modulating topo II activity may also affect the response to therapy. Studies evaluating different parameters that can modulate topo II activity and the response to the drugs targeting the enzyme are necessary.

A set of genes that regulate cell proliferation predicts treatment outcome in childhood acute lymphoblastic leukemia

To identify novel predictors of outcome in childhood acute lymphoblastic leukemia (ALL), we analyzed gene expression in the leukemic cells of 187 children with newly diagnosed ALL and compared the findings with minimal residual disease (MRD) results obtained on day 19 of remission induction treatment. Genes that showed a significant relationship to MRD were then tested for their capacity to predict leukemic relapse in an independent cohort of 99 patients. We identified 674 probe sets that were associated with MRD on day 19 (P < .006); 40 of the identified genes predicted relapse (P < .03). Among these, 14 showed independent prognostic significance after adjustment for age, leukocyte count at diagnosis, and genetic subtype. More than half of the 40 genes and nearly all of the 14 genes were functionally related, as indicated by their roles in the regulation of cell proliferation. Underexpression of genes promoting cell proliferation was associated with resistance to chemotherapy. The biologic processes regulated by the genes we identified appear to be key determinants of the early cytoreductive response to remission induction therapy and subsequent clinical outcome in childhood ALL. Incorporation of the expression levels of these genes into existing strategies of risk classification could improve clinical management.

Pathologic complete remission rate after cisplatin-based primary chemotherapy in breast cancer: correlation with p63 expression

PURPOSE

p63, a gene that shares structural and functional homologies with p53, codes for different isoforms, with (TA) and without (DeltaN) transactivating properties. The anti-apoptotic DeltaN isoform is often expressed in breast cancer (BC). DNA damaging drugs such as cisplatin (C) induce its degradation and stabilization of the TA, proapoptotic isoform. This supports the role of these drugs in the treatment of tumors expressing p63. The aim of the present study was to ascertain the predictive value of p63 immunoreactivity in patients treated preoperatively with regimens including cisplatin and/or anthracyclines.

METHODS

We reviewed the pretreatment biopsies of 189 patients with large or locally advanced BC (cT1-4d, N0-2, M0) treated with preoperative chemotherapy, performing p63 immunohistochemistry. The rate of pathological complete remission (pCR) at final surgery was assessed with respect to cisplatin administration and p63 immunoreaction.

RESULTS

pCR was identified in 20 patients (11%); 147 patients (78%) had an objective response, 39 (21%) stable disease, and 3 (1%) disease progression. One hundred forty seven patients (78%) received a cisplatin-containing regimen. Only regimens including cisplatin without anthracyclines yielded a higher rate of pCR in p63-positive compared with p63-negative tumors (23 vs. 0%, P=0.048). No significant difference in the pCR rate was observed for regimens containing anthracycline without cisplatin.

CONCLUSIONS

Administration of cisplatin without anthracyclines correlates with a high rate of pCR after primary chemotherapy in patients with p63-positive BC. The role of cisplatin-based chemotherapy should be further studied in these patients.

Effect of structural modification at the 4, 3', and 2' positions of doxorubicin on topoisomerase II poisoning, apoptosis, and cytotoxicity in human melanoma cells

Introduction:

The mechanism of the cytotoxicity of anthracyclines is pleiotropic and its significance in cell growth inhibition seems to be highly specific and dependent on cell type and anthracycline drug. Resistance and the high cardiotoxicity of anthracyclines have stimulated many studies aimed at identifying critical substituents required for optimal activity. Many authors point to the fact that the double-strand breaks, the consequence of the activity of topoisomerase II poisons, and the inability of cells to repair the DNA lesions are the signal for apoptosis. The aim of this study was to define the influence of 4-demetoxy 2′-halogenated analogs with altered basicity at the 3′-position on topoisomerase II and the relationship of that interaction with apoptosis and the cytotoxicity of these novel anthracyclines. Parental human ME18 melanoma cells and the ME18/R subline, obtained experimentally, resistant to doxorubicin (DOX), exposed to 1.7 and 8.6 µM DOX or its analogs, annamycin and WP903 (both 0.3 and 3.0 µM) were studied.

Materials and Methods:

The MTT test was used to assay cytotoxicity. Interaction of the drugs with topoisomerase II and apoptosis were done by Western blot and fluorescence microscopy using Hoechst 33342.

Results:

The structural changes at positions 4, 2′, and 3′ can influence topoisomerase II interaction and apoptotic activity, although correlation between these events and cytotoxic consequences has not been proved.

Conclusions:

The biological response of the cells to the structurally similar anthracyclines may be variable and probably depends on the cell type which seems to be an additional problem in the multifactorial resistance of tumor cells to anthracyclines.

HER2 expression and efficacy of preoperative paclitaxel/FAC chemotherapy in breast cancer

PURPOSE

We examined the correlation between HER2 expression and pathologic complete response (pCR) to paclitaxel/FAC (T/FAC) preoperative chemotherapy in breast cancer.

PATIENTS AND METHODS

Retrospective analysis of data including 534 patients treated with preoperative T/FAC was performed. Gene expression results were available from two datasets of 132 and 286 patients, and were used to examine the co-expression of HER2 and topoisomerase II alpha (TOP2A) and microtubule associated protein tau (MAP-Tau).

RESULTS

Of the 534 patients, 105 (20%) had HER2-overexpressing breast cancer. The pCR rates were 33% and 15% for patients with HER2+ and HER2- tumors (P<0.001). The 5-year relapse-free survival rates were 94% and 70% in HER2+ tumors with and without pCR (P=0.009). HER2 overexpression (odds ratio 2.3, 95%CI: 1.3-3.9, P=0.004), estrogen receptor (ER) status, grade and weekly schedule of paclitaxel were each significantly and independently associated with pCR in multivariate analysis. When patients were stratified by ER status, the pCR rates were 50% for HER2+/ER-, 30% for HER2-/ER-, 19% for HER2+/ER+, and 6% for HER2-/ER+ tumors. HER2 overexpression was associated with lower expression of MAP-tau (P=0.001 and P<0.001) and higher expression of TOP2A mRNAs (P=0.048 and P=0.001) in patients with ER+ disease. ER- cancers had low MAP-tau expression regardless of HER-status.

CONCLUSION

HER2 overexpression is associated with higher rate of pCR to preoperative T/FAC chemotherapy regardless of ER status. HER2 overexpression also correlates with increased TOP2A and decreased MAP-tau expression in ER-positive cancers.

Pharmacodiagnostics and Targeted Therapies—A Rational Approach for Individualizing Medical Anticancer Therapy in Breast Cancer

The selection of therapy for a particular breast cancer patient is traditionally based on average results from randomized clinical trials. Rational pharmacotherapy is in essence about selecting the right drug(s) for the right patient, and in order to guide this selection process pharmacodiagnostic tests are indispensable. A number of tests have been developed or are under development for targeted therapies, such as antiestrogens, human epidermal growth factor receptor 2 inhibitors, and topoisomerase inhibitors. Based on a biopsy from the tumor, the tests are able to identify patients with a high probability to benefit from these therapies. The detection of the predictive biomarkers is based on different technologies, such as immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization. Pharmacodiagnostic tests will play an important role in the further development of targeted therapies and may be seen as a prerequisite for the introduction of individualized medicine in oncology.