Amplification of the TOP2A gene does not predict high levels of topoisomerase II alpha protein in human breast tumor samples

In Silico and In Vitro Studies of Novel Azomethines on DNA Repair Genes in Gastric Cell Lines

We herein report the determination of the cytotoxic activity and expression profiles of some DNA repair genes of newly synthesized azomethines in the gastric cancer cell line (AGS). The studied novel compounds were synthesized by a condensation reaction and received compounds were characterized by 1H and 13C NMR spectroscopy methods. Furthermore, they were applied to the AGS cell line at eight different concentrations (0.1-50 µg/mL). Anticancer activities were determined using the MTT method. Expression levels of ATR, ERCC1, TOP2A, and ABCB1 genes were determined by the RT-PCR method. Biochemical parameters were also examined. The interaction of proteins with other proteins was investigated with the String v11 program. The IC50 values of compounds 1, 2, and 3 obtained after 72 h were 23.10, 8.93, and 1.58 µg/mL, respectively. The results demonstrate that the cytotoxic activity of compound 3 on AGS cancer cells is higher in comparison with other molecules. It was determined that the expression levels of ATR, TOP2A, and ABCB1 genes in compounds 1, 2, and 3 were decreased compared to the control group. In addition, it was determined that ERCC1 gene expression increased in compound 3, decreased in compound 2, and remained unchanged in compound 1 (p < 0.001). In AGS gastric cancer cells, a 64% decrease was detected for GST levels in compound 1, while a 38% decrease in GSH levels in compound 2. In addition, compounds 1-3 were examined at the molecular level with computational techniques and the docking studies revealed 4LN0 as a target protein.

Cryptolepine Targets TOP2A and Inhibits Tumor Cell Proliferation in Breast Cancer Cells - An in vitro and in silico Study

BACKGROUND

DNA Topoisomerase II Alpha (TOP2A), a protein-coding gene, is central to the replication process and has been found deregulated in several malignancies, including breast cancer. Several therapeutic regimens have been developed and approved for targeting TOP2A and have prolonged the survival of cancer patients. However, due to the inherent nature of the tumor cell to evolve, the earlier positive response turns into a refractory chemoresistance in breast cancer patients.

OBJECTIVE

The study's main objective was to analyze the expression pattern and prognostic significance of TOP2A in breast cancer patients and screen new therapeutic molecules targeting TOP2A.

METHODS

We utilized an integrated bioinformatic approach to analyze the expression pattern, genetic alteration, immune association, and prognostic significance of TOP2A in breast cancer (BC) and screened natural compounds targeting TOP2A, and performed an in-silico and an in vitro analysis.

RESULTS

Our study showed that TOP2A is highly overexpressed in breast cancer tissues and overexpression of TOP2A correlates with worse overall survival (OS) and relapse-free survival (RFS). Moreover, TOP2A showed a high association with tumor stroma, particularly with myeloid-derived suppressor cells. Also, in silico and in vitro analysis revealed cryptolepine as a promising natural compound targeting TOP2A.

CONCLUSION

Cumulatively, this study signifies that TOP2A promotes breast cancer progression, and targeting TOP2A in combination with other therapeutic agents will significantly enhance the response of BC patients to therapy and reduce the development of chemoresistance.

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.

Prognostic and predictive value of the combination of TOP2A and HER2 in node-negative tumors 2 cm or smaller (T1N0) breast cancer

BACKGROUND

We aim to evaluate the prognostic and predictive value of TOP2A and HER2 expression in T1N0 breast cancer patients.

METHODS

299 cases with T1N0 breast cancer were obtained from the Oncomine database (Cohort 1) and 963 of T1N0 breast cancer patients from Sun Yat-sen Memorial Hospital (Cohort 2) were retrospectively enrolled. Kaplan-Meier product was applied to estimate survival curve. Cox proportional hazard models was used to identify prognostic factors. We used PSM (propensity score matching) to balance clinicopathologic characteristics among four groups of different HER2/TOP2A status. Survival between groups and chemotherapy regimens were analyzed, before and after PSM.

RESULTS

In Cohort 1, we found that the group with HER2+ and higher expression of TOP2A mRNA was associated with poor breast cancer-specific survival (BCSS) compared to the group of HER2- with lower expression of TOP2A mRNA. In Cohort 2, HER2+ patients with higher TOP2A protein expression had greater risk of recurrence and distant recurrence compared to HER2- patients with lower expression of TOP2A protein. Among the patients who developed both HER2+ and higher expression of TOP2A protein and received chemotherapy, patients who received an anthracycline-based regimen had a significantly better recurrence-free survival (RFS) than those with a non-anthracycline-based regime.

CONCLUSION

Patients with both HER2+ and high expression level of TOP2A protein predicts poor prognosis in T1N0 breast cancer patients. Patients with double positive for TOP2A protein and HER2 may benefit from anthracycline-based regimens.

Assessment of ERBB2 and TOP2α gene status and expression profile in feline mammary tumors: findings and guidelines

In humans, the ERBB2 gene amplification and overexpression are biomarkers for invasive breast cancer and a therapeutic target. Also, TOP2α gene aberrations predict the response to anthracycline-based adjuvant chemotherapy. Although feline mammary tumors (FMTs) are good models in comparative oncology, scarce data is available regarding the ERBB2 and TOP2α status. In this study, and for the first time, the ERBB2 DNA status and RNA levels of intracellular (ICD) and extracellular (ECD) coding regions were compared with TOP2α gene status and expression profile, in samples of FMTs and disease-free tissues from the same animal. Results showed that ERBB2 and TOP2α gene status are highly correlated (r=0.87, p<0.0001, n=25), with few tumor samples presenting amplification. Also, the majority of the FMTs showed ERBB2 overexpression coupled with TOP2α overexpression (r=0.87, p<0.0001, n=27), being the ERBB2-ICD and ECD transcripts highly correlated (r=0.97, p<0.0001, n=27). Significant associations were found between TOP2α gene status or ERBB2 and TOP2α RNA levels with several clinicopathological parameters. This work highlights the need of experimental designs for a precise evaluation of ERBB2 and TOP2α gene status and its expression in FMTs, to improve their clinical management and to further validate them as a suitable model for comparative oncology studies.

Mutual regulation of MDM4 and TOP2A in cancer cell proliferation

MDM4 and topoisomerase IIα (TOP2A) are overexpressed in various human cancers. MDM4 acts as an oncoprotein which promotes cancer progression by inhibiting tumor suppressor p53. As a DNA replication- and cell division-regulating enzyme, TOP2A is the main target of many anticancer therapy regimens; however, the exact role of TOP2A in cancer remains elusive. Herein, we report that MDM4 and TOP2A bind to each other and are mutually upregulated at the post-translational level, leading to TOP2A protein stabilization, inhibition of p53, and increased tumor-cell proliferation. We demonstrate that the C-terminal region (CTR) of TOP2A binds to a unique sequence (residues: 188-238) of MDM4, which contains an auto-inhibitory segment regulating the MDM4-p53 interaction. TOP2A binding in turn activates MDM4 for p53 binding, resulting in enhanced inhibition of p53 and cancer cell proliferation. Conversely, binding of the MDM4 sequence to the CTR of TOP2A stabilizes TOP2A protein, leading to increased TOP2A protein expression. These results reveal novel functions of MDM4 and TOP2A as well as their interactions in oncogenesis, suggesting that inhibition of the MDM4-TOP2A interaction may represent a novel strategy in specifically and simultaneously targeting TOP2A and MDM4 for cancer treatment.

Impact of Topoisomerase IIα, PTEN, ABCC1/MRP1, and KI67 on triple-negative breast cancer patients treated with neoadjuvant chemotherapy

PURPOSE

Triple-negative breast cancer (TNBC) patients with residual disease following neoadjuvant chemotherapy (NAC) harbor higher risk of relapse, and eventual demise compared to those who achieve pathologic complete response. Therefore, in this study, we assessed a panel of molecules involved in key pathways of drug resistance and tumor progression before and after NAC in TNBC patients, in order to clarify the underlying mechanisms.

METHODS

We studied 148 TNBC Japanese patients treated with anthracycline/taxane-based NAC. KI67, Topoisomerase IIα (TopoIIα), PTEN, p53, Bcl2, vimentin, ABCG2/BCRP1, ABCB1/MDR1, and ABCC1/MRP1 were immunolocalized in surgical pathology materials before and after NAC.

RESULTS

The status of vimentin and increasing labeling index (LI) of TopoIIα and KI67 in biopsy specimens were significantly associated with those who responded to NAC treatment. The abundance of p53 (p = 0.003), ABCC1/MRP1 (p = 0.033), ABCB1/MDR1 (p = 0.022), and a loss of PTEN (p < 0.0001) in surgery specimens following treatment were associated with pathologic parameters. TopoIIα, PTEN, and ABCC1/MRP1 status predicted pathologic response. In addition, the status of PTEN, ABCC1/MRP1, ABCB1/MDR1, Bcl2, and vimentin in surgical specimens was also significantly associated with adverse clinicopathological factors in surgery specimens, suggesting that these alterations could be responsible for tumor relapse in TNBC patients.

CONCLUSION

KI67, TopoIIα, PTEN, and ABCC1/MRP1 status could predict treatment response and/or eventual clinical outcomes. These results could also provide an insight into the mechanisms of drug resistance and relapse of TNBC patients receiving NAC.

Overexpression of topoisomerase II alpha protein is a factor for poor prognosis in patients with luminal B breast cancer

Background

The prognostic value and the best method of testing of topoisomerase II alpha (TOP2A) status have not been established in modern tailored therapy based on breast cancer subtype.

Results

The frequencies of TOP2A overexpression and TOP2A amplified were 55.8% and 9.5%, respectively. TOP2A overexpression correlated strongly with non-luminal A subtype (χ²-test, p < 0.001). TOP2A overexpression was significantly associated with relapse-free survival in luminal B breast cancer (n = 316; log rank test, p < 0.001) but not in other breast cancer subtypes. Cox regression analysis showed that TOP2A overexpression is a significant prognostic factor in luminal B breast cancer (hazard ratio (HR) 4.00, 95% confidence interval (CI) 1.65–9.54, p = 0.002). TOP2A amplified was recognized in HER2 positive breast cancer (p < 0.001). In HER2 positive breast cancer, TOP2A amplified (HR 0.30, 95% CI 0.085–1.07, p = 0.063) appeared to be a better prognostic factor.

Conclusion

In modern tailored therapy, TOP2A overexpression can be a poor prognostic factor in luminal B breast cancer. In contrast, TOP2A amplified could be a better prognostic factor in HER2 positive breast cancer.

Materials and methods

Between May 2005 and April 2015, a total of 643 consecutive non-metastatic invasive breast cancers were evaluated for TOP2A amplified using fluorescence in situ hybridization analysis (FISH) and for TOP2A overexpression using the immunohistochemistry assay. FISH ratios of 2 or higher were designated as TOP2A amplified, and TOP2A staining >10% was defined as TOP2A overexpression. The prognostic values of TOP2A amplified and TOP2A overexpression were retrospectively evaluated.

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.

The prognostic significance of topoisomerase II alpha protein in early stage luminal breast cancer

BACKGROUND

Topoisomerase II alpha (TOP2A) protein has been shown to be a proliferation marker associated with tumor grade and Ki67 index. The prognostic effect of TOP2A seems different among different subtypes of breast cancer. The current study evaluated the prognostic impact of TOP2A protein on luminal breast cancer.

METHOD

Altogether 434 stage I-II luminal breast cancer patients who underwent curative surgery in Sun Yat-Sen University Cancer Center between 2007 and 2009 were enrolled. TOP2A protein expression was assessed by immunohistochemistry. Clinical and pathological data were retrospectively collected.

RESULT

With a cut-off value of 30%, 127 (29.3%) patients were classified as TOP2A overexpression. TOP2A overexpression was associated with a higher tumor grade and Ki67 index. Patients with TOP2A high expression showed a significantly higher rate of distant metastasis and shorter distant metastasis free survival (DMFS) compared with patients with low TOP2A expression. The prognostic influence of TOP2A expression was more significant in years 5-8 after diagnosis, and more pronounced in stage II patients, luminal B disease, and patients treated with adjuvant endocrine therapy alone. Multivariate survival analysis revealed TOP2A overexpression was an independent fact for worse DMFS.

CONCLUSION

TOP2A protein showed a time dependent influence on prognosis in stage I-II luminal breast cancer, suggesting it might be a potential predictor of late recurrence for this group of patients.

Clinical Significance of Subtype Classification in Metastatic Lymph Nodes of Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy

Background

Neoadjuvant chemotherapy has been increasingly utilized in the treatment of breast cancer patients. However, there are no established surrogate markers predicting the response to subsequent adjuvant therapy and clinical outcome of patients. In particular, whether primary or lymph nodes metastasis should be evaluated for these analyses has remained unknown. Therefore, in this study, we first evaluated the differences in biomarkers between primary and metastatic cancer tissues in the patients undergoing neoadjuvant chemotherapy. We then correlated the findings with the clinical outcomes of these patients.

Methods

We examined 49 patients receiving neoadjuvant chemotherapy and subsequent surgery with lymph node metastasis. Estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2) and Ki-67 were all immunohistochemically evaluated in core needle biopsy samples from primary and metastatic tumors following chemotherapy.

Results

No statistically significant differences in these markers were detected between the primary tumor and metastatic lymph nodes following therapy, but the Ki-67 labeling index was significantly higher in metastatic lymph nodes than in primary tumor (p = 0.017). The patients associated with luminal A type carcinoma in their lymph nodes following chemotherapy demonstrated significantly better clinical outcomes (disease-free survival: p = 0.0045, overall survival: p = 0.0006) than those who were not.

Conclusion

These data indicate that subtype classification following chemotherapy, in the metastatic lymph nodes rather than primary tumor could predict long-term outcomes of patients undergoing neoadjuvant chemotherapy.

Cancer Hallmarks, Biomarkers and Breast Cancer Molecular Subtypes

Breast cancer is a complex disease encompassing multiple tumor entities, each characterized by distinct morphology, behavior and clinical implications. Besides estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, novel biomarkers have shown their prognostic and predictive values, complicating our understanding towards to the heterogeneity of such cancers. Ten cancer hallmarks have been proposed by Weinberg to characterize cancer and its carcinogenesis. By reviewing biomarkers and breast cancer molecular subtypes, we propose that the divergent outcome observed from patients stratified by hormone status are driven by different cancer hallmarks. 'Sustaining proliferative signaling' further differentiates cancers with positive hormone receptors. 'Activating invasion and metastasis' and 'evading immune destruction' drive the differentiation of triple negative breast cancers. 'Resisting cell death', 'genome instability and mutation' and 'deregulating cellular energetics' refine breast cancer classification with their predictive values. 'Evading growth suppressors', 'enabling replicative immortality', 'inducing angiogenesis' and 'tumor-promoting inflammation' have not been involved in breast cancer classification which need more focus in the future biomarker-related research. This review novels in its global view on breast cancer heterogeneity, which clarifies many confusions in this field and contributes to precision medicine.

Multi-platform profiling of over 2000 sarcomas: identification of biomarkers and novel therapeutic targets

Background: Drug development in sarcoma has been hampered by the rarity and heterogeneity of the disease and lack of predictive biomarkers to therapies. We assessed protein expression and gene alterations in a large number of bone and soft tissue sarcomas in order to categorize the molecular alterations, identify predictive biomarkers and discover new therapeutic targets. Methods: Data from sarcoma specimens profiled for protein expression, gene amplification/translocation and DNA sequencing was reviewed. Results: 2539 sarcoma specimens of 22 subtypes were included. TOPO2A was the most overexpressed protein at 52.8%. There was overexpression or loss of other sarcoma relevant proteins such as SPARC, PTEN and MGMT. Approximately 50% of the sarcomas expressed PD-L1 by IHC and presented with PD-1+ TILs, notably the LMS, chondrosarcomas, liposarcomas and UPS. Gene amplification/rearrangement of ALK, cMYC, HER2, PIK3CA, TOPO2A and cMET was relatively uncommon. EGFR gene amplification occurred at a rate of 16.9%. DNA sequencing of 47 genes identified mutations in 47% of the samples. The most commonly mutated genes were TP53 (26.3%) and BRCA2 (17.6%). Overexpression of TOPO2A was associated with TP53 mutation (P = 0.0001). Conclusion: This data provides the landscape of alterations in sarcoma. Future clinical trials are needed to validate these targets.

Triple-negative breast cancer exhibits a favorable response to neoadjuvant chemotherapy independent of the expression of topoisomerase IIα

The present study retrospectively analyzed the utility of topoisomerase IIα expression as a prognostic marker to predict the neoadjuvant chemotherapeutic response and survival among different breast cancer subtypes. The patients were subtyped and the expression of topoisomerase IIα was determined using immunohistochemistry. All patients (n=147) received an anthracycline-containing regimen preoperatively, and 139 (95%) patients also received docetaxel. Of the 147 patients, 25 (17%) were triple-negative and 20 (17%) were human epidermal growth factor receptor 2 (HER2)-positive. Among these subtypes, a significantly higher a rate (P<0.0001) and higher incidence of topoisomerase IIα expression (P=0.036) were observed compared with that in the hormone receptor-positive and HER2-negative breast cancer types. However, the expression of topoisomerase IIα revealed no correlation with the treatment response or survival in any of the subtypes. Therefore, these results indicated that the favorable response to anthracycline-containing chemotherapy among triple-negative and HER2-positive breast cancer was independent of the expression of topoisomerase IIα.

An overview of triple negative breast cancer for surgical oncologists

Triple negative breast cancers (TNBCs) represent a distinct subgroup of breast cancers with an immunohistochemical phenotype that is negative for oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2). The aim of this article is to provide a broad overview of recent developments in the diagnosis and management of TNBC for surgical oncologists. This overview discusses the subtypes of TNBC and the relationship between this type of breast cancer and the BRCA1 gene. In addition, the article explores recent advances in the treatment of TNBC from a surgical, radiation, and medical oncology point of view. Lastly, evolving therapeutic strategies that have potential to enhance outcomes for patients with TNBC are also discussed.

Predicting Anthracycline Benefit: TOP2A and CEP17-Not Only but Also

PURPOSE

Evidence supporting the clinical utility of predictive biomarkers of anthracycline activity is weak, with a recent meta-analysis failing to provide strong evidence for either HER2 or TOP2A. Having previously shown that duplication of chromosome 17 pericentromeric alpha satellite as measured with a centromere enumeration probe (CEP17) predicted sensitivity to anthracyclines, we report here an individual patient-level pooled analysis of data from five trials comparing anthracycline-based chemotherapy with CMF (cyclophosphamide, methotrexate, and fluorouracil) as adjuvant chemotherapy for early breast cancer.

PATIENTS AND METHODS

Fluorescent in situ hybridization for CEP17, HER2, and TOP2A was performed in three laboratories on samples from 3,846 of 4,864 eligible patients from five trials evaluating anthracycline-containing chemotherapy versus CMF. Methodologic differences did not affect HER2-to-CEP17 ratios but necessitated different definitions for CEP17 duplication: > 1.86 observed copies per cell for BR9601, NEAT, Belgian, and DBCG89D trials and > 2.25 for the MA.5 trial.

RESULTS

Fluorescent in situ hybridization data were available in 89.3% (HER2), 83.9% (CEP17), and 80.6% (TOP2A) of 3,846 patient cases with available tissue. Both CEP17and TOP2A treatment-by-marker interactions remained significant in adjusted analyses for recurrence-free and overall survival, whereas HER2 did not. A combined CEP17 and TOP2A-adjusted model predicted anthracycline benefit across all five trials for both recurrence-free (hazard ratio, 0.64; 95% CI, 0.51 to 0.82; P = .001) and overall survival (hazard ratio, 0.66; 95% CI, 0.51 to 0.85; P = .005).

CONCLUSION

This prospectively planned individual-patient pooled analysis of patient cases from five adjuvant trials confirms that patients whose tumors harbor either CEP17 duplication or TOP2A aberrations, but not HER2 amplification, benefit from adjuvant anthracycline chemotherapy.

TOP2A amplification and overexpression in hepatocellular carcinoma tissues

Hepatocellular carcinoma (HCC) is the leading cause of cancer death in men worldwide owing to limited insights into pathogenesis and unsatisfactory efficacy of current therapies. HER2 and TOP2A genes are coamplified in breast and some other cancers. In this study, we investigated gene aberrations of HER2 and TOP2A and protein expressions of HER2, TOP2A, Ki-67, and p53 in tumor and matched nontumor tissues, as well as their associations with clinicopathological features. Gene aberrations were evaluated by FISH and protein expressions by IHC. Neither HER2 overexpression nor HER2 gene amplification was observed in both tumor tissues and matched nontumor tissues. By contrast, TOP2A overexpression was detected in 72.5% of tumor tissues but not detected in matched nontumor tissues. However, TOP2A gene amplification was not observed in both tumor and matched nontumor tissues. TOP2A overexpression was significantly associated with HCC tumor tissues (P < 0.001), hepatitis B surface antigen (HBsAg) in the serum (P = 0.004), and Ki-67 (P = 0.038) but not with age, tumor size, alpha-fetoprotein, TP53, and copy number of TOP2A gene and chromosome 17 centromere. In conclusion, TOP2A overexpression in HCC was not secondary to gene amplification. In addition, neither HER2 amplification nor overexpression could be used as prognostic and predictive marker in HCC.

Topoisomerase IIα in chromosome instability and personalized cancer therapy

Genome instability is a hallmark of cancer cells. Chromosome instability (CIN), which is often mutually exclusive from hypermutation genotypes, represents a distinct subtype of genome instability. Hypermutations in cancer cells are due to defects in DNA repair genes, but the cause of CIN is still elusive. However, because of the extensive chromosomal abnormalities associated with CIN, its cause is likely a defect in a network of genes that regulate mitotic checkpoints and chromosomal organization and segregation. Emerging evidence has shown that the chromosomal decatenation checkpoint, which is critical for chromatin untangling and packing during genetic material duplication, is defective in cancer cells with CIN. The decatenation checkpoint is known to be regulated by a family of enzymes called topoisomerases. Among them, the gene encoding topoisomerase IIα (TOP2A) is commonly altered at both gene copy number and gene expression level in cancer cells. Thus, abnormal alterations of TOP2A, its interacting proteins, and its modifications may play a critical role in CIN in human cancers. Clinically, a large arsenal of topoisomerase inhibitors have been used to suppress DNA replication in cancer. However, they often lead to the secondary development of leukemia because of their effect on the chromosomal decatenation checkpoint. Therefore, topoisomerase drugs must be used judiciously and administered on an individual basis. In this review, we highlight the biological function of TOP2A in chromosome segregation and the mechanisms that regulate this enzyme's expression and activity. We also review the roles of TOP2A and related proteins in human cancers, and raise a perspective for how to target TOP2A in personalized cancer therapy.

TOP2A protein by quantitative immunofluorescence as a predictor of response to epirubicin in the neoadjuvant treatment of breast cancer

Aim: Anthracyclines are commonly used in breast cancer, although they lack validated predictive biomarkers. We explored the interaction between TOP2A protein by quantitative immunofluorescence (QIF) and anthracycline sensitivity. Patients & methods: Patients with estrogen receptor-negative breast cancer received neoadjuvant epirubicin. Pretreatment biopsies were analyzed using AQUA®. Total, cytoplasmic (C) and nuclear (N) TOP2A protein concentrations were expressed as QIF scores and compared with pathologic complete response (pCR), TOP2A by immunohistochemistry, TOP2A mRNA, TOP2A and HER2 gene status, and Ki-67 level. Results: In total, 76 cases were assessable. C, N, and total scores did not correlate with pCR, or other markers. The N:C ratio differed significantly by HER2 status. No pCRs occurred in patients in the lowest N:C quartile. Conclusion: Although no relevant correlation between TOP2A QIF scores and pCR was found, N:C ratio may have a negative predictive role, and may merit further exploration in a multifactorial predictive model that includes tumor and host factors.

TOP2A overexpression as a poor prognostic factor in patients with nasopharyngeal carcinoma

Despite the advances in diagnostic imaging and treatment modalities, the risk stratification and final outcomes in patients with nasopharyngeal carcinomas (NPC) still remain suboptimal. Through data mining from published transcriptomic database, topoisomerase IIα (TOP2A) was first identified as a differentially upregulated gene in NPC tissues, which implicates cell division via selective cleavage, rearrangement, and re-ligation of DNA strands. Given the roles of TOP2A in prognostication and in the frontline therapeutic regimen of common carcinomas, such as breast cancer, we explored TOP2A immunoexpression status and its associations with clinicopathological variables and survival in a well-defined cohort of NPC patients. TOP2A immunohistochemistry was retrospectively performed and analyzed using H-score method for biopsy specimens from 124 NPC patients who received standard treatment without distant metastasis at initial diagnosis. Those cases with H-score larger than the median value were construed as featuring TOP2A overexpression. The findings were correlated with the clinicopathological variables, disease-specific survival (DSS) and distant metastasis-free survival (DMFS). TOP2A overexpression was significantly associated with American Joint of Cancer Committee (AJCC) stages III-IV (p = 0.019) and univariately predictive of adverse outcomes for DSS (p = 0.0078) and DMFS (p = 0.0003). In the multivariate comparison, TOP2A overexpression remained prognostically independent to portend worse DSS (p = 0.047, hazard ratio = 1.732) and DMFS (p = 0.003, hazard ratio = 2.569), together with advanced AJCC stages III-IV. TOP2A expression is upregulated in a subset of NPCs and its increased immunoexpression significantly correlated with advanced stages and tumor aggressiveness, justifying the potentiality of TOP2A as a prognostic biomarker and a novel therapeutic target of NPC.

The HER2 amplicon in breast cancer: Topoisomerase IIA and beyond

HER2 gene amplification is observed in about 15% of breast cancers. The subgroup of HER2-positive breast cancers appears to be heterogeneous and presents complex patterns of gene amplification at the locus on chromosome 17q12-21. The molecular variations within the chromosome 17q amplicon and their clinical implications remain largely unknown. Besides the well-known TOP2A gene encoding Topoisomerase IIA, other genes might also be amplified and could play functional roles in breast cancer development and progression. This review will focus on the current knowledge concerning the HER2 amplicon heterogeneity, its clinical and biological impact and the pitfalls associated with the evaluation of gene amplifications at this locus, with particular attention to TOP2A and the link between TOP2A and anthracycline benefit. In addition it will discuss the clinical and biological implications of the amplification of ten other genes at this locus (MED1, STARD3, GRB7, THRA, RARA, IGFPB4, CCR7, KRT20, KRT19 and GAST) in breast cancer.

Prognostication of prostate cancer based on TOP2A protein and gene assessment: TOP2A in prostate cancer

Background

TOP2A encodes for topoisomerase IIα, a nuclear enzyme that controls DNA topological structure and cell cycle progression. This enzyme is a marker of cell proliferation in normal and neoplastic tissues; however, little information is available about its expression in prostate cancer (PCa).

Methods

Immunohistochemistry (IHC) was automated using mouse monoclonal antibody against TOP2A (clone SWT3D1; DAKO, Carpenteria, CA, USA) at dilution 1:800 and Flex Plus detection system in autostainer 48Ultra (DAKO). FISH was performed using TOP2A (17q21)/ CEP17 probe kit (Kreateck Biotechnology, San Diego, CA, USA). Biochemical and pathological data from 193 patients with PCa were retrieved for the analysis, whose significance was considered when p < 0.05. Also, fractal analysis was performed in a subset of 20 randomly selected cases.

Results

TOP2A protein expression correlated with higher Gleason scores and higher levels of preoperative PSA (p = 0.018 and p = 0.011). Patients with higher levels of TOP2A presented shorter biochemical recurrence-free survival (BRFS) (p = 0.001). In multivariate analysis, we found that TOP2A remained an independent prognostic factor of BRFS, with a relative risk of 1.98 (p = 0.001; 95% CI, 1.338–2.93); thus, cases that expressed high levels of this enzyme had a shorter BRFS compared with TOP2A-negative or TOP2A-low cases. No alterations in TOP2A gene status nor correlation between FISH and IHC results were observed. Concerning fractal analysis, patients who expressed higher levels of TOP2A have angiolymphatic invasion and presented higher Gleason scores (p = 0.033 and p = 0.025, respectively). Also, patients with higher expression of TOP2A presented shorter BRFS (p = 0.001).

Conclusions

This is the first study to perform TOP2A protein and gene digital assessment and fractal analysis in association with BRFS in a large series of PCa. Also, we show that TOP2A gene copy number alterations are not observed in this type of tumor. So, higher protein expression of TOP2A is not related to gene amplification in PCa. Furthermore, TOP2A protein assessment has prognostic importance and, due to its relation with poor outcome, TOP2A IHC evaluation in the biopsy can represent an important tool for selecting the most suitable surgical and clinical approach for patients with PCa.

Dual functions of the homeoprotein DLX4 in modulating responsiveness of tumor cells to topoisomerase II-targeting drugs

Topoisomerase II (TOP2)-targeting poisons such as anthracyclines and etoposide are commonly used for cancer chemotherapy and kill tumor cells by causing accumulation of DNA double-strand breaks (DSB). Several lines of evidence indicate that overexpression of TOP2A, the gene encoding topoisomerase IIα, increases sensitivity of tumor cells to TOP2 poisons, but it is not clear why some TOP2A-overexpressing (TOP2A-High) tumors respond poorly to these drugs. In this study, we identified that TOP2A expression is induced by DLX4, a homeoprotein that is overexpressed in breast and ovarian cancers. Analysis of breast cancer datasets revealed that TOP2A-high cases that also highly expressed DLX4 responded more poorly to anthracycline-based chemotherapy than TOP2A-high cases that expressed DLX4 at low levels. Overexpression of TOP2A alone in tumor cells increased the level of DSBs induced by TOP2 poisons. In contrast, DLX4 reduced the level of TOP2 poison-induced DSBs irrespective of its induction of TOP2A. DLX4 did not stimulate homologous recombination-mediated repair of DSBs. However, DLX4 interacted with Ku proteins, stimulated DNA-dependent protein kinase activity, and increased erroneous end-joining repair of DSBs. Whereas DLX4 did not reduce levels of TOP2 poison-induced DSBs in Ku-deficient cells, DLX4 stimulated DSB repair and reduced the level of TOP2 poison-induced DSBs when Ku was reconstituted in these cells. Our findings indicate that DLX4 induces TOP2A expression but reduces sensitivity of tumor cells to TOP2 poisons by stimulating Ku-dependent repair of DSBs. These opposing activities of DLX4 could explain why some TOP2A-overexpressing tumors are not highly sensitive to TOP2 poisons.

Prognostic significance of TOP2A gene dosage in HER-2-negative breast cancer

BACKGROUND

Previous studies showed the prognostic and predictive impact of human epidermal growth factor receptor 2 (HER-2) gene alterations analyzed separately and jointly with topoisomerase II α (TOP2A) gene alterations; however, the role of TOP2A gene abnormalities alone has not been thoroughly investigated. Additionally, TOP2A aberrations were typically studied in HER-2-positive (HER-2(+)) tumors because these genes are frequently coamplified. Therefore, the knowledge concerning the impact of TOP2A abnormalities in HER-2-negative (HER-2(-)) patients is scarce. This study aimed to investigate the clinical significance of TOP2A anomalies in breast cancer patients with HER-2(-) and HER-2(+) tumors.

MATERIALS AND METHODS

Snap-frozen tumor samples from 322 consecutive stage I-III breast cancer patients were analyzed for TOP2A gene dosage using quantitative real-time PCR (qPCR).

RESULTS

A high TOP2A gene dosage was found in 94 tumors (29%)-32% and 27% of HER-2(+) and HER-2(-) tumors, respectively. The mean TOP2A gene dosages in the HER-2(+) and HER-2(-) groups were 1.49 ± 1.03 and 1.09 ± 0.35, respectively. High TOP2A gene dosage had an inverse prognostic impact in terms of shorter disease-free survival (DFS) and overall survival (OS) times in the entire group and in both the HER-2(-) and HER-2(+) subgroups. The unfavorable prognostic impact of TOP2A gene dosage was maintained in the multivariate Cox regression analysis in the entire group and in HER-2(-) patients.

CONCLUSIONS

A high gene dosage of TOP2A determined using qPCR occurs frequently both in HER-2(+) and HER-2(-) tumors and has a strong adverse prognostic impact.

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).

HER2 and TOP2A in high-risk early breast cancer patients treated with adjuvant epirubicin-based dose-dense sequential chemotherapy

Background

HER2 and TOP2A parameters (gene status, mRNA and protein expression) have individually been associated with the outcome of patients treated with anthracyclines. The aim of this study was to comprehensively evaluate the prognostic/predictive significance of the above parameters in early, high-risk breast cancer patients treated with epirubicin-based, dose-dense sequential adjuvant chemotherapy.

Methods

In a series of 352 breast carcinoma tissues from patients that had been post-operatively treated with epirubicin-CMF with or without paclitaxel, we assessed HER2 and TOP2A gene status (chromogenic in situ hybridization), mRNA expression (quantitative reverse transcription PCR), as well as HER2 and TopoIIa protein expression (immunohistochemistry).

Results

HER2 and TOP2A amplification did not share the same effects on their downstream molecules, with consistent patterns observed in HER2 mRNA and protein expression according to HER2 amplification (all parameters strongly inter-related, p values < 0.001), but inconsistent patterns in the case of TOP2A. TOP2A gene amplification (7% of all cases) was not related to TOP2A mRNA and TopoIIa protein expression, while TOP2A mRNA and TopoIIa protein were strongly related to each other (p < 0.001). Hence, TOP2A amplified tumors did not correspond to tumors with high TOP2A mRNA or TopoIIa protein expression, while the latter were characterized by high Ki67 scores (p = 0.003 and p < 0.001, respectively). Multivariate analysis adjusted for nodal involvement, hormone receptor status, Ki67 score and HER2/TOP2A parameters revealed HER2/TOP2A co-amplification (21.2% of HER2 amplified tumors) as an independent favorable prognostic factor for DFS (HR = 0.13, 95% CI: 0.02-0.96, p = 0.046); in contrast, increased HER2/TOP2A mRNA co-expression was identified as an independent adverse prognostic factor for both DFS (HR = 2.41, 95% CI: 1.31-4.42, p = 0.005) and OS (HR = 2.83, 95% CI: 1.42-5.63, p = 0.003), while high TOP2A mRNA expression was an independent adverse prognostic factor for OS (HR = 2.06, 95% CI: 1.23-3.46, p = 0.006). None of the parameters tested was associated with response to paclitaxel.

Conclusions

This study confirms the favorable prognostic value of HER2/TOP2A co-amplification and the adverse prognostic value of high TOP2A mRNA expression extending it to the adjuvant treatment setting in early high-risk breast cancer. The strong adverse prognostic impact of high HER2/TOP2A mRNA co-expression needs further validation in studies designed to evaluate markers predictive for anthracyclines.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12611000506998.

HER2 and TOP2A as predictive markers for anthracycline-containing chemotherapy regimens as adjuvant treatment of breast cancer: a meta-analysis of individual patient data

BACKGROUND

Prediction of response to anthracycline-based therapy for breast cancer is challenging. We aimed to assess the value of HER2 and TOP2A as predictive markers of response to anthracycline-based adjuvant therapy in patients with early breast cancer.

METHODS

We did a meta-analysis of individual patient data from five randomised adjuvant trials that compared anthracycline-based regimens with cyclophosphamide, methotrexate, and fluorouracil (CMF) regimens. We assessed the status of HER2 and TOP2A genes with fluorescent in-situ hybridisation. Tumour samples were submitted to an external laboratory for validation. We calculated hazard ratios (HR) to compare event-free survival (EFS) and overall survival in patients receiving anthracycline-based treatment with those receiving CMF in two HER2 cohorts (HER2 amplified and non-amplified tumours) and in three TOP2A cohorts (normal, amplified, and deleted tumours).

FINDINGS

We analysed data for 3452 patients for HER2 and 3102 patients for TOP2A. For EFS, HRs were 0·89 (95% CI 0·79-1·01) for HER2 non-amplified patients and 0·71 (0·58-0·86) for HER2-amplified patients (p(interaction)=0·0485); for overall survival, HRs were 0·91 (95% CI 0·79-1·05) for HER2 non-amplified patients and 0·73 (0·59-0·89) for HER2-amplified patients (p(interaction)=0·0718). In analysis of TOP2A status, HRs for EFS were 0·88 (0·78-1·00) for normal, 0·63 (0·46-0·87) for deleted, and 0·62 (0·43-0·90) for amplified (p(interaction)=0·0513); HRs for overall survival were 0·89 (0·78-1·03) for normal, 0·68 (0·49-0·95) for deleted, and 0·67 (0·46-0·98) for amplified (p(interaction)=0·1608). When patients with TOP2A-deleted and TOP2A-amplified tumours were grouped together (altered cohort) and compared with data from patients with normal TOP2A tumours, HRs for EFS were 0·64 (0·50-0·81) for altered and 0·88 (0·78-1·00) for normal (p(interaction)=0·0183); HRs for overall survival were 0·67 (0·52-0·86) for altered and 0·89 (0·78-1·03) for normal (p(interaction)=0·0455).

INTERPRETATION

Although HER2 amplification and combined TOP2A amplification and deletion may have some value in the prediction of responsiveness to anthracycline-based chemotherapy, our findings do not support the use of anthracyclines only in patients with HER2-amplified or TOP2A-aberrated tumours.

FUNDING

Associazione Italiana Ricerca Cancro, Academy of Finland, Belgian Federation Against Cancer, Cancer Research UK, Les Amis de l'Institut Bordet, Scottish Breast Cancer Trials Group, NCIC Clinical Trials Group, Canadian Cancer Society Research Institute, Danish Council for Strategic Research, Pharmacia-Upjohn (now Pfizer), and Abbott Laboratories.

Assessment of Topoisomerase II α status in breast cancer by quantitative PCR, gene expression microarrays, immunohistochemistry, and fluorescence in situ hybridization

Anthracyclines are frequently used for the treatment of breast cancer and topoisomerase II alpha (TOP2A) is considered to be the molecular target. Numerous studies have evaluated the predictive value of TOP2A using different methodological approaches and inconsistent results have been reported. Indeed, the correlation between techniques for the assessment of TOP2A status has not been well evaluated. In this study, we determined TOP2A status in 61 breast tumor samples by real-time PCR, DNA microarrays, immunohistochemistry (IHC), and fluorescence in situ hybridization (FISH), and then evaluated these results with clinical-pathological features and breast cancer intrinsic subtypes. First, we observed a statistical significant correlation of TOP2A gene expression between real-time PCR and microarrays (Pearson coefficient, 0.816; P < 0.001), and both predicted TOP2A IHC results fairly well (area under the curve > 0.74). In contrast, poor agreement between FISH and IHC data was observed (k: 0.134). Secondly, TOP2A expression was found significantly associated with cell proliferation, and with the highly proliferative Luminal B, Her2-enriched and Basal-like intrinsic subtypes. In conclusion, TOP2A expression in breast cancer was associated with high proliferation and aggressive tumor subtypes and appears to be independent of its amplification status. All of these features should be taken into consideration when assessing the predictive value of TOP2A for anthracycline-based chemotherapy.

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.

TOP2A amplification in the absence of that of HER-2/neu: toward individualization of chemotherapeutic practice in breast cancer

PRIMARY OBJECTIVE

To investigate the relationship between human epidermal growth factor receptor (HER)-2/neu and the gene encoding topoisomerase IIα (TOP2A) in breast cancer, while elucidating their association with clinicopathological variables.

METHODS

Real-time quantitative polymerase chain reaction (RQ-PCR) was performed on a 96-patient study group to assess gene amplification, and levels were determined using the comparative cycle threshold approach and Taqman assays. An immunohistochemistry (IHC) microarray (n = 76) was then employed to check for correlation between gene amplification and protein expression levels.

RESULTS

Amplification levels of TOP2A did not differ significantly according to HER-2/neu status by either RQ-PCR or IHC microarray. Of the HER-2/neu(-) patients, 29.1% demonstrated levels of TOP2A above the third quartile, whereas 22.9% of the HER-2/neu(+) patients had values in the first quartile (log TOP2A <0.62), thereby indicating low-level amplification. Of the 60 patients characterized as HER-2/neu(-) using IHC and fluorescence in situ hybridization (FISH), 22.9% were classified as TOP2A(+) on the IHC microarray. Of the 14 patients deemed HER-2/neu(+) using IHC and FISH, meanwhile, the majority (n = 10) were classified as TOP2A(+).

CONCLUSIONS

Our results indicate that amplification of TOP2A in breast cancer is not confined to those who are concomitantly HER-2/neu(+), and suggest that a significant proportion of HER-2/neu(-) patients exhibit high levels of TOP2A.

Tumour topoisomerase II alpha protein expression and outcome after adjuvant dose-dense anthracycline-based chemotherapy

There is a need for the selection of those breast cancers where benefit may be attained from the addition of an anthracycline to the adjuvant chemotherapy. The expression of topoisomerase II alpha (TOP2A) protein in 3 cohorts of breast cancers treated with adjuvant dose-dense anthracycline-based chemotherapy was determined retrospectively. The TOP2A status was analysed in relation with the other standard tumour features and the outcome. TOP2A IHC results were assessable in 106 patients: with a cut-off value of 15%, 48% of the tumours were classified as TOP2A-positive. The expression of TOP2A correlated with that of Ki67 (R = 0.532, p < 0.001) and a high grade (p = 0.04), but did not correlate with the proportion of ER- or PR-positive cells in the tumour. More tumors were TOP2A-negative among the ER- or PR-positive cancers than among the ER/PR-negative cancers (p = 0.021 and p = 0.002, respectively). After a median follow-up time of 64.5 months, 31 relapses (23.5%) and 23 deaths (17.4%) had occurred in 131 patients. The overall survival was longer in the TOP2A-positive cases than in the TOP2A-negative cases. The recurrence-free survival and the overall survival were significantly more favourable in the ER/PR-negative and TOP2A-positive tumours than in other subgroups. In a Cox proportional hazards model, the grade and TOP2A remained significant determinants in the ER/PR-negative subgroup. TOP2A positivity and grade 3 indicated a decrease in the risk of death with HR = 0.211 (95% CI: 0.042-1.05, p = 0.056) and HR = 0.216 (95% CI: 0.047-0.990, p = 0.048), respectively. A higher sensitivity to anthracycline-containing regimens is suggested in ER/PR-negative and TOP2A-positive cancers.

Molecular assays in breast cancer pathology

Recent advances in understanding the molecular pathology of breast cancer offer significant potential to identify patients who may benefit from adjuvant therapies. To date, few of these advances are utilised in a routine setting. We review molecular assays that are currently in use or are in the advanced stages of development, which may be used as predictive or prognostic biomarkers in breast cancer.The only widely used breast cancer molecular assay is in situ hybridisation (ISH) for human epidermal growth factor receptor 2 (HER2) gene amplification and we highlight key issues with the interpretation of this assay, with particular attention to the difficulties of the equivocal category. New molecular assays such as ISH for the topoisomerase II alpha (TOP2A) gene and for the aberrations in the copy number of the centromeric region of chromosome 17 are readily performed in a standard histopathology laboratory, but to date there are insufficient data to support their routine use. We also review the current data on two commercially available multigene expression assays, Oncotype DX and MammaPrint and discuss their potential use. Overall, while new molecular assays have significant potential to improve patient selection for therapy, well-performed histopathology with reliable interpretation of standard hormone and HER2 assays provides the most important predictive and prognostic information in early breast cancer.

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.

Prognostic potential of topoisomerase IIα and HER2 in a retrospective analysis of early advanced breast cancer patients treated with adjuvant anthracycline chemotherapy

BACKGROUND

After surgery and anthracycline adjuvant treatment, about 60% of early advanced breast cancer patients develop recurrence. These differences in treatment outcome indicate the need to identify markers for risk of recurrence. The aim of this study was the retrospective analysis of relationship between tumour features (topoisomerase IIα (TOPOIIα), human epidermal growth factor receptor 2 (HER2), hormone receptors, cytokeratin (CK)5/6 expression and proliferation rate) and disease-free survival (DFS) of breast cancer patients treated with anthracyclines in adjuvant setting.

MATERIAL AND METHODS

The study was performed in the group of 172 patients (mean age: 52.8 years, T1-T2, N1-N2, M0). HER2, TOPOIIα, estrogen receptor (ER) and progesterone receptor (PgR) expression and proliferation rate were studied immunohistochemically. HER2 overexpression was confirmed by fluorescence in situ hybridisation (FISH). These data were correlated with 5-year DFS.

RESULTS

In univariate analysis, lower TOPOIIα expression (median value ≤ 11.9%) and tumour grade G1 + G2 were favourable prognostic factors. All tumours were classified into four subtypes: (1) lower TOPOIIα expression and G1 + G2, (2) lower TOPOIIα expression and G3, (3) higher TOPOIIα expression and G3, and (4) higher TOPOIIα expression and G1 + G2. In Cox multivariate regression analysis, tumour subtype distinguished by TOPOIIα expression and grade was independent prognostic factor for DFS. All patients (n = 52) with TOPOIIα lower expression and G1 + G2 tumours, survived 5 years without any evidence of disease.

CONCLUSION

The results suggest that lower TOPOIIα expression and lower tumour grade are favourable prognostic factors for early advanced breast cancer patients after adjuvant anthracycline chemotherapy.

Genomic predictors of response to doxorubicin versus docetaxel in primary breast cancer

Taxanes and anthracyclines improve the outcome of early breast cancer, although the benefit is limited to a small proportion of patients and are toxic. We prospectively looked for predictors of response to these drugs.

EXPERIMENTAL DESIGN

Four cycles of doxorubicin (75 mg/m²) or docetaxel (100 mg/m²) were compared as presurgical chemotherapy for breast cancer. Biomarkers were determined by immunohistochemistry and fluorescent in situ hybridization using prechemotherapy core biopsies. Tumors were also classified into one of the molecular intrinsic subtypes using an immunohistochemical panel of five biomarkers and genomic profiles. Single genes and intrinsic subtypes were correlated with response to doxorubicin versus docetaxel. Among the 204 evaluable patients, significant predictors of sensitivity in multivariate analysis were low topo2a expression and ER-negative status for doxorubicin and small tumor size and ER-negative status for docetaxel. Predictors of resistance in multivariate analysis were triple-negative status (ER/PgR/HER2 negative by IHC/FISH) for doxorubicin, and high TNM stage for docetaxel. Triple-negative tumors were associated with topo2a overexpression more than the other subtypes. In 94 patients with gene expression profiles, docetaxel was superior to doxorubicin in the basal-like subtype (good pathological response rate - PCR + class I of 56 vs. 0%; P = 0.034); no significant differences were observed in the other subtypes when comparing these two drugs. Low topo2a expression and ER-negative status were predictors of response to doxorubicin, while small tumor size and ER-negative status predicted response to docetaxel. Docetaxel was superior to doxorubicin in triple-negative/basal-like tumors, while no significant differences were seen in the remaining intrinsic subtypes.

The ability of biomarkers to predict systemic progression in men with high-risk prostate cancer treated surgically is dependent on ERG status

The objective of this study was to assess the relationship of the tumor protein levels of TOP2A and MIB-1 and ERG status with cancer-specific outcomes in men with high-risk prostate cancer treated by radical prostatectomy (RP). A 150-pair case-control study was designed from RP patients who developed systemic progression (SP) within 6 years of RP (cases) and men who were free of disease at least 8 years after RP (controls). The cases and controls were matched on conventional prognostic clinical parameters. TOP2A and MIB-1 levels were assessed by immunohistochemical methods, and ERG status was assessed by quantitative reverse transcription-PCR. The prognostic abilities of TOP2A and MIB-1 were significantly better in ERG(-) patients, and TOP2A was superior to MIB-1. In receiver operating characteristic analysis, the TOP2A and MIB-1 scores exhibited AUCs of 0.81 and 0.78 for ERG(-) patients, versus 0.67 and 0.68 for ERG(+) patients, respectively. Clinical parameters attained an AUC of 0.65 in ERG(-) patients and 0.54 in ERG(+) patients. When both markers were incorporated into a model for ERG(-) patients, the AUC increased to 0.83, with TOP2A showing a stronger association with SP than MIB-1. The time to SP was significantly associated with TOP2A; higher 5-year SP rates were observed in patients with higher TOP2A protein levels. In addition, although patient numbers are small, the response to adjuvant androgen deprivation therapy is associated with ERG status, showing more significant treatment effect in ERG(+) patients.

TOPOIIalpha and HER-2/neu overexpression/amplification in Barrett's oesophagus, dysplasia and adenocarcinoma

Rossi E, Villanacci V, Bassotti G, Donato F, Festa A, Cengia G, Grisanti S & Cestari R (2010) Histopathology57, 81–89 TOPOIIα and HER-2/neu overexpression/amplification in Barrett’s oesophagus, dysplasia and adenocarcinoma

High-resolution genomic and expression analyses of copy number alterations in HER2-amplified breast cancer

INTRODUCTION

HER2 gene amplification and protein overexpression (HER2+) define a clinically challenging subgroup of breast cancer with variable prognosis and response to therapy. Although gene expression profiling has identified an ERBB2 molecular subtype of breast cancer, it is clear that HER2+ tumors reside in all molecular subtypes and represent a genomically and biologically heterogeneous group, needed to be further characterized in large sample sets.

METHODS

Genome-wide DNA copy number profiling, using bacterial artificial chromosome (BAC) array comparative genomic hybridization (aCGH), and global gene expression profiling were performed on 200 and 87 HER2+ tumors, respectively. Genomic Identification of Significant Targets in Cancer (GISTIC) was used to identify significant copy number alterations (CNAs) in HER2+ tumors, which were related to a set of 554 non-HER2 amplified (HER2-) breast tumors. High-resolution oligonucleotide aCGH was used to delineate the 17q12-q21 region in high detail.

RESULTS

The HER2-amplicon was narrowed to an 85.92 kbp region including the TCAP, PNMT, PERLD1, HER2, C17orf37 and GRB7 genes, and higher HER2 copy numbers indicated worse prognosis. In 31% of HER2+ tumors the amplicon extended to TOP2A, defining a subgroup of HER2+ breast cancer associated with estrogen receptor-positive status and with a trend of better survival than HER2+ breast cancers with deleted (18%) or neutral TOP2A (51%). HER2+ tumors were clearly distinguished from HER2- tumors by the presence of recurrent high-level amplifications and firestorm patterns on chromosome 17q. While there was no significant difference between HER2+ and HER2- tumors regarding the incidence of other recurrent high-level amplifications, differences in the co-amplification pattern were observed, as shown by the almost mutually exclusive occurrence of 8p12, 11q13 and 20q13 amplification in HER2+ tumors. GISTIC analysis identified 117 significant CNAs across all autosomes. Supervised analyses revealed: (1) significant CNAs separating HER2+ tumors stratified by clinical variables, and (2) CNAs separating HER2+ from HER2- tumors.

CONCLUSIONS

We have performed a comprehensive survey of CNAs in HER2+ breast tumors, pinpointing significant genomic alterations including both known and potentially novel therapeutic targets. Our analysis sheds further light on the genomically complex and heterogeneous nature of HER2+ tumors in relation to other subgroups of breast cancer.

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.

17q12-21 - the pursuit of targeted therapy in breast cancer

PURPOSE

Identification of HER2/neu, and the subsequent development of targeted therapy for patients who over-express it, has revolutionized their management. Research has since focused on the area of chromosome 17 in which HER2/neu is located in order to identify other genes in the vicinity. The aims of this review are, firstly, to discuss current thinking in relation to the role of these genes in the pathogenesis of breast cancer and, secondly, to examine how this evidence may be assimilated such that new forms of targeted therapy can be developed.

EXPERIMENTAL DESIGN

This review discusses the evidence in relation to 4 genes located at the HER2/neu amplicon, namely TOP2A, GRB7, STARD3 and RARA.

RESULTS

TOP2A has aroused particular interest as over-expression of its protein has been shown to correlate, both with amplification of HER2/neu, and with response to anthracycline-based chemotherapeutic agents in breast cancer. GRB7 is included on Oncotype DXtm, and has recently been implicated in gastric and oesophageal cancer. STARD3 and RARA also hold clinical relevance, the former having been shown to function in steroidogenesis and therefore implicated in hormone-receptor-positive breast cancer. Finally, RARA may be the key to unlocking the problem of resistance to all-trans retinoic acid (ATRA) in breast cancer sufferers; this treatment has previously been demonstrated to induce remission in over 80% of patients with acute promyelocytic leukaemia (APML).

CONCLUSION

These genes hold potential as therapeutic targets, and warrant further investigation as we move towards our goal of individually tailored therapeutic strategies in breast cancer.

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.

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.

Simultaneous detection of TOP2A and HER2 gene amplification by multiplex ligation-dependent probe amplification in breast cancer

HER-2/neu gene amplification, found in certain subtypes of (breast-) cancers, is an independent prognostic factor of poor outcome and determines eligibility for systemic treatment with trastuzumab. TopoII alpha (TOP2A) gene amplification seems to be predictive of response to a class of cytostatic agents called TopoII inhibitors, which include the anthracyclines. The observed increased efficacy of anthracyclines in HER2-positive tumors is thought to arise from the close proximity of both genes on chromosome 17, where the TopoII amplification status will determine the anthracycline sensitivity. This study aimed to validate a new polymerase chain reaction-based test, called multiplex ligation-dependent probe amplification (MLPA), as a simple and quick method to simultaneously assess HER-2/neu and TopoII alpha gene amplification status in paraffin-embedded breast cancer samples. To this end, MLPA results were compared with TopoII alpha, HER2 chromogenic in situ hybridization (CISH). We also assessed TopoII alpha protein expression by immunohistochemistry. Of 353 patients, 9% showed TopoII alpha amplification by MLPA and 13% of patients were HER2 amplified. TopoII alpha amplification was seen in 42% of HER2-amplified cases and showed no high level amplification without HER2 amplification. Eleven patients displayed TopoI alpha loss (3%). Concordance between MLPA and CISH was 91% for TopoII alpha and 96% for HER2. Correlation between amplification and overexpression of TopoII alpha was significant (P=0.035), but amplification did not always predict protein overexpression. Loss of the TopoII alpha gene was almost never associated with loss of its protein. In conclusion, MLPA is an easy and accurate method to simultaneously detect breast cancer HER-2/neu and TopoII alpha copy number status in paraffin-embedded tissue, and thus an attractive supplement or alternative to CISH.