Lack of independent prognostic and predictive value of centromere 17 copy number changes in breast cancer patients with known HER2 and TOP2A status

Patterns of Chromosomal Instability and Clonal Heterogeneity in Luminal B Breast Cancer: A Pilot Study

Chromosomal instability (CIN), defined by variations in the number or structure of chromosomes from cell to cell, is recognized as a distinctive characteristic of cancer associated with the ability of tumors to adapt to challenging environments. CIN has been recognized as a source of genetic variation that leads to clonal heterogeneity (CH). Recent findings suggest a potential association between CIN and CH with the prognosis of BC patients, particularly in tumors expressing the epidermal growth factor receptor 2 (HER2+). In fact, information on the role of CIN in other BC subtypes, including luminal B BC, is limited. Additionally, it remains unknown whether CIN in luminal B BC tumors, above a specific threshold, could have a detrimental effect on the growth of human tumors or whether low or intermediate CIN levels could be linked to a more favorable BC patient prognosis when contrasted with elevated levels. Clarifying these relationships could have a substantial impact on risk stratification and the development of future therapeutic strategies aimed at targeting CIN in BC. This study aimed to assess CIN and CH in tumor tissue samples from ten patients with luminal B BC and compare them with established clinicopathological parameters. The results of this study reveal that luminal B BC patients exhibit intermediate CIN and stable aneuploidy, both of which correlate with lymphovascular invasion. Our results also provide valuable preliminary data that could contribute to the understanding of the implications of CIN and CH in risk stratification and the development of future therapeutic strategies in BC.

Novel Criteria for Intratumoral Budding with Prognostic Relevance for Colon Cancer and Its Histological Subtypes

Peritumoral budding and intratumoral budding (ITB) are important prognostic factors for colorectal cancer patients. Scientists worldwide have investigated the role of budding in tumor progression and its prognosis, but guidelines for reliably identifying tumor buds based on morphology are lacking. In this study, next-generation tissue microarray (ngTMA^®) construction was used for tumor bud evaluation, and highly detailed rule-out annotation was used for tumor definition in pancytokeratin-stained tissue sections. Initially, tissues of 245 colon cancer patients were evaluated with high interobserver reliability, and a concordance of 96% was achieved. It was shown that high ITB scores were associated with poor distant metastasis-free survival (p = 0.006 with a cut-off of ≥10 buds). This cut-off was defined as the best maximum value from one of two/three ngTMA^® cores (0.6 mm diameter). ITB in 30 cases of mucinous, medullary, and signet ring cell carcinoma was analyzed for the subsequent determination of differences in tumor bud analyses between those subtypes. In conclusion, blinded randomized punched cores in the tumor center can be useful for ITB detection. It can be assumed that this method is suitable for its adoption in clinical routines.

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.

FISH Analysis of TOP2A and HER-2 Aberrations in Female Breast Carcinoma on Archived Material: Egyptian NCI Experience

BACKGROUND

HER-2 and TOP2A genes are considered of great importance in breast cancer. Their copy number variability has been proposed to be a marker for the degree of chromosomal instability. Owing to the close proximity of TOP2A gene to HER-2 gene chromosome 17, TOP2A status is believed to affect therapeutic plan. The percentage of TOP2A aberrations is greatly variable among different studies.

AIM OF WORK

Is to investigate the relation between TOP2A and HER-2 gene amplification using fluorescence in situ hybridization technique.

MATERIALS AND METHODS

Archival blocks of 112 breast cancer Egyptian female patients were retrieved from the pathology department at NCI, Cairo University were retrieved and investigated using fluorescence in situ hybridization technique for TOP2A and HER-2 gene assessment. In addition, correlation with some clinicopathologic parameters was done.

RESULTS

HER-2 gene amplification was encountered in about 33% of cases. TOP2A gene amplification and deletion were detected in 23.9% and 2.8% of studied cases. Moderate agreement was obtained between results of HER-2 gene and TOP2A gene amplification.

CONCLUSIONS

HER-2 and TOP2A genes amplification are 2 separate genetic yet closely related events in breast cancer. Polysomy of chromosome 17 is proposed to be an early event in occurrence of TOP2A gene amplification. Further studies regarding effect of TOP2A gene in response to anthracyclines in Egyptian population should be planned for to establish its role in therapeutic planning.

Centromere 17 copy number gain reflects chromosomal instability in breast cancer

Chromosomal instability (CIN) is known to be associated with prognosis and treatment response in breast cancer. This study was conducted to determine whether copy number gain of centromere 17 (CEP17) reflects CIN, and to evaluate the prognostic and predictive value of CIN in breast cancer. CIN status was determined by summing copy number gains of four centromeric probes (CEP1, CEP8, CEP11, and CEP16) based on fluorescence in situ hybridization and CIN scores were calculated using next generation sequencing data. High CIN was associated with adverse clinicopatholgical parameters of breast cancer. Among them, positive HER2 status, high Ki-67 index and CEP17 copy number gain were found to be independent predictors of high CIN. High CIN was associated with poor clinical outcome of the patients in the whole group, as well as in luminal/HER2-negative and HER2-positive subtypes. CEP17 copy number was significantly higher in the high-CIN-score group than in the low-CIN-score group. A positive linear correlation between the mean CEP17 copy number and the CIN score was found. In conclusion, CEP17 copy number was confirmed as a useful predictor for CIN in breast cancer, and high CIN was revealed as an indicator of poor prognosis in breast cancer.

HER2 status in breast cancer: changes in guidelines and complicating factors for interpretation

Human epidermal growth factor receptor 2 (HER2) protein overexpression and/or HER2 gene amplification is found in about 20% of invasive breast cancers. It is a sole predictive marker for treatment benefits from HER2 targeted therapy and thus, HER2 testing is a routine practice for newly diagnosed breast cancer in pathology. Currently, HER2 immunohistochemistry (IHC) is used for a screening test, and in situ hybridization is used as a confirmation test for HER2 IHC equivocal cases. Since the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines on HER2 testing was first released in 2007, it has been updated to provide clear instructions for HER2 testing and accurate determination of HER2 status in breast cancer. During HER2 interpretation, some pitfalls such as intratumoral HER2 heterogeneity and increase in chromosome enumeration probe 17 signals may lead to inaccurate assessment of HER2 status. Moreover, HER2 status can be altered after neoadjuvant chemotherapy or during metastatic progression, due to biologic or methodologic issues. This review addresses recent updates of ASCO/CAP guidelines and factors complicating in the interpretation of HER2 status in breast cancers.

Prognostic significance of centromere 17 copy number gain in breast cancer depends on breast cancer subtype

Increased copy number of chromosome enumeration probe (CEP) targeting centromere 17 is frequently encountered during HER2 in situ hybridization (ISH) in breast cancer. The aim of this study was to clarify the clinicopathologic significance of CEP17 copy number gain in a relatively large series of breast cancer patients. We analyzed 945 cases of invasive breast cancers whose HER2 fluorescence ISH reports were available from 2004 to 2011 at a single institution and evaluated the association of CEP17 copy number gain with clinicopathologic features of tumors and patient survival. We detected 186 (19.7%) cases of CEP17 copy number gain (CEP17≥3.0) among 945 invasive breast cancers. In survival analysis, CEP17 copy number gain was not associated with disease-free survival of the patients in the whole group. Nonetheless, it was found to be an independent adverse prognostic factor in the HER2-negative group but not in the HER2-positive group. In further subgroup analyses, CEP17 copy number gain was revealed as an independent poor prognostic factor in HER2-negative and hormone receptor-positive breast cancers, and it was associated with aggressive histologic variables including high T stage, high histologic grade, lymphovascular invasion, p53 overexpression, and high Ki-67 proliferative index. In conclusion, we found that elevated CEP17 count can serve as a prognostic marker in luminal/HER2-negative subtype of invasive breast cancer. We advocate the use of the dual-colored fluorescence ISH using CEP17 rather than the single-colored one because it gives additional valuable information on CEP17 copy number alterations.

WSB1: from homeostasis to hypoxia

The wsb1 gene has been identified to be important in developmental biology and cancer. A complex transcriptional regulation of wsb1 yields at least three functional transcripts. The major expressed isoform, WSB1 protein, is a substrate recognition protein within an E3 ubiquitin ligase, with the capability to bind diverse targets and mediate ubiquitinylation and proteolytic degradation. Recent data suggests a new role for WSB1 as a component of a neuroprotective pathway which results in modification and aggregation of neurotoxic proteins such as LRRK2 in Parkinson’s Disease, via an unusual mode of protein ubiquitinylation.

WSB1 is also involved in thyroid hormone homeostasis, immune regulation and cellular metabolism, particularly glucose metabolism and hypoxia. In hypoxia, wsb1 is a HIF-1 target, and is a regulator of the degradation of diverse proteins associated with the cellular response to hypoxia, including HIPK2, RhoGDI2 and VHL. Major roles are to both protect HIF-1 function through degradation of VHL, and decrease apoptosis through degradation of HIPK2. These activities suggest a role for wsb1 in cancer cell proliferation and metastasis. As well, recent work has identified a role for WSB1 in glucose metabolism, and perhaps in mediating the Warburg effect in cancer cells by maintaining the function of HIF1. Furthermore, studies of cancer specimens have identified dysregulation of wsb1 associated with several types of cancer, suggesting a biologically relevant role in cancer development and/or progression.

Recent development of an inducible expression system for wsb1 could aid in the further understanding of the varied functions of this protein in the cell, and roles as a potential oncogene and neuroprotective protein.

Topoisomerase-1 and -2A gene copy numbers are elevated in mismatch repair-proficient colorectal cancers

INTRODUCTION

Topoisomerase 1 (TOP1) and 2A (TOP2A) are potential predictive biomarkers for irinotecan and anthracycline treatment, respectively, in colorectal cancer (CRC), and we have recently reported a high frequency of gene gain of the TOP1 and TOP2A genes in CRC. Furthermore, Mismatch Repair (MMR) subtypes of CRC have been associated with benefit from adjuvant chemotherapy of primary CRC. Given the involvement of the topoisomerase enzymes in DNA replication and repair, we raised the hypothesis that an association may exist between TOP gene copy numbers and MMR proficiency/deficiency in CRC.

MATERIAL AND METHODS

Test cohort: FISH analysis with an in-house TOP1/CEN20 probe mix and a commercially available TOP2A/CEN17 (Dako, Glostrup, Denmark) probe mix was performed on archival formalin fixed paraffin embedded (FFPE) tissue samples from 18 patients with proficient MMR (pMMR) CRC and 18 patients with deficient MMR (dMMR) CRC. TOP1 and TOP2A gene copy numbers and their ratios per nucleus were correlated with MMR status using the Mann-Whitney test. Validation cohort: FFPE samples from 154 patients with primary stage III CRC (originally included in the RANX05 study) were classified according to MMR status by immunohistochemical analysis using validated antibodies for MLH1, MLH2, MSH6 and PMS2, and information on TOP1, CEN20, TOP2A and CEN17 status was previously published for this cohort.

RESULTS

The observed TOP1 gene copy numbers in the 36 CRC test cohort were significantly greater (p < 0.01) in the pMMR subgroup (mean: 3.84, SD: 2.03) than in the dMMR subgroup (mean: 1.50, SD: 0.12). Similarly, the TOP2A copy numbers were significantly greater (p < 0.01) in the pMMR subgroup (mean: 1.99, SD: 0.52) than in the dMMR subgroup (mean: 1.52, SD: 0.10). These findings were confirmed in the validation cohort, where in the pMMR subgroup 51% had ≥2 extra TOP1 copies per cell, while all tumors classified as dMMR had diploid TOP1 status and mean TOP2A copy numbers were 2.30 (SD: 1.36) and 1.80 (SD: 0.31) (p = 0.01) in the pMMR subgroup vs. dMMR subgroup, respectively.

DISCUSSION AND CONCLUSION

Our results show that TOP1 and TOP2A gene copy numbers are increased in the pMMR subgroup. We propose that this preference may reflect a selective pressure to gain and/or maintain the gained extra copies of topoisomerase genes whose products are required to cope with high replication stress present in the pMMR tumors, thereby providing a survival advantage selectively in pMMR tumors. Future studies should test this concept and explore potential differences between pMMR and dMMR tumors in response to Top1 and Top2 inhibitors.

Multi-colour FISH in oesophageal adenocarcinoma-predictors of prognosis independent of stage and grade

BACKGROUND

Oesophageal adenocarcinoma or Barrett's adenocarcinoma (EAC) is increasing in incidence and stratification of prognosis might improve disease management. Multi-colour fluorescence in situ hybridisation (FISH) investigating ERBB2, MYC, CDKN2A and ZNF217 has recently shown promising results for the diagnosis of dysplasia and cancer using cytological samples.

METHODS

To identify markers of prognosis we targeted four selected gene loci using multi-colour FISH applied to a tissue microarray containing 130 EAC samples. Prognostic predictors (P1, P2, P3) based on genomic copy numbers of the four loci were statistically assessed to stratify patients according to overall survival in combination with clinical data.

RESULTS

The best stratification into favourable and unfavourable prognoses was shown by P1, percentage of cells with less than two ZNF217 signals; P2, percentage of cells with fewer ERBB2- than ZNF217 signals; and P3, overall ratio of ERBB2-/ZNF217 signals. Median survival times for P1 were 32 vs 73 months, 28 vs 73 months for P2; and 27 vs 65 months for P3. Regarding each tumour grade P2 subdivided patients into distinct prognostic groups independently within each grade, with different median survival times of at least 35 months.

CONCLUSIONS

Cell signal number of the ERBB2 and ZNF217 loci showed independence from tumour stage and differentiation grade. The prognostic value of multi-colour FISH-assays is applicable to EAC and is superior to single markers.

TOP2A gene copy number change in breast cancer

Aims

The clinical significance of TOP2A as a prognostic marker has not been clarified. The aims of this study were to investigate the frequency of TOP2A copy number change; to correlate TOP2A with HER2 status, hormone receptor (HR) status and molecular subtype, and further to explore differences in breast cancer-specific survival according to TOP2A and HER2.

Methods

In this study, TOP2A, HER2 and chromosome 17 copy number were assessed in 670 cases of breast cancer using in situ hybridisation techniques. Gene to chromosome ratios ≥2 were classified as amplification. TOP2A deletion (gene to chromosome ratio ≤0.8) or monosomy (only one signal for both gene and chromosome in more than 75% of nuclei) were classified as gene loss.

Results

A strong association between TOP2A change and HR and HER2 status was found. During the first 5 years after diagnosis, the risk of death from breast cancer was significantly higher for cases with HER2 amplification irrespective of TOP2A status.

Conclusions

TOP2A copy number change was strongly associated with HR and HER2 status and as a prognostic marker TOP2A is probably of limited value.

Underpinning the repurposing of anthracyclines towards colorectal cancer: assessment of topoisomerase II alpha gene copy number alterations in colorectal cancer

OBJECTIVE. We propose a repurposing strategy where anthracyclines are reintroduced to a subgroup of patients with metastatic colorectal cancer with the highest likelihood of response. In breast cancer, DNA topoisomerase II alpha gene (TOP2A) alterations predict incremental benefit of anthracyclines, but this association has not been investigated in colorectal cancer. Frequency analysis of TOP2A gene alterations in colorectal cancer and the association with prognosis are evaluated and the challenges of using a TOP2A/CEN-17 FISH probe combination are addressed. MATERIAL AND METHODS. Formalin-fixed, paraffin-embedded material from 154 stage III colorectal cancer patients included in the RANX05 clinical trial was retrospectively assessed for TOP2A gene alterations using FISH. The TOP2A/CEN-17 ratio as well as the TOP2A gene copy number alone was used to define gene alterations and associations between gene status and outcomes were analyzed. RESULTS. TOP2A gene gain was a frequent finding with 9.8 % having a total of ≥4 TOP2A copies per cell. According to the TOP2A/CEN-17 ratio, 10.5 % had TOP2A gene gain. Polysomy or gain of the centromere region of chromosome-17 was not as frequent as reported in breast cancer. No prognostic characteristic of TOP2A was identified. CONCLUSION. TOP2A gene gain is present in numbers relevant to identify a subgroup of patients who may benefit from anthracycline therapy. Based on the present findings, we will initiate a prospective clinical trial designed to evaluate this hypothesis in patients with metastatic colorectal cancer who have failed 5-fluorouracil and oxaliplatin chemotherapy.

Mechanisms of topoisomerase I (TOP1) gene copy number increase in a stage III colorectal cancer patient cohort

BACKGROUND

Topoisomerase I (Top1) is the target of Top1 inhibitor chemotherapy. The TOP1 gene, located at 20q12-q13.1, is frequently detected at elevated copy numbers in colorectal cancer (CRC). The present study explores the mechanism, frequency and prognostic impact of TOP1 gene aberrations in stage III CRC and how these can be detected by fluorescent in situ hybridization (FISH).

METHODS

Nine CRC cell line metaphase spreads were analyzed by FISH with a TOP1 probe in combination with a reference probe covering either the centromeric region of chromosome 20 (CEN-20) or chromosome 2 (CEN-2). Tissue sections from 154 chemonaive stage III CRC patients, previously studied with TOP1/CEN-20, were analyzed with TOP1/CEN-2. Relationships between biomarker status and overall survival (OS), time to recurrence (TTR) in CRC and time to local recurrence (LR; rectal cancer only) were determined.

RESULTS

TOP1 aberrations were observed in four cell line metaphases. In all cell lines CEN-2 was found to reflect chromosomal ploidy levels and therefore the TOP1/CEN-2 probe combination was selected to identify TOP1 gene gains (TOP1/CEN-2≥1.5). One hundred and three patients (68.2%) had TOP1 gain, of which 15 patients (14.6%) harbored an amplification (TOP1/CEN-20≥2.0). TOP1 gene gain did not have any association with clinical endpoints, whereas TOP1 amplification showed a non-significant trend towards longer TTR (multivariate HR: 0.50, p = 0.08). Once amplified cases were segregated from other cases of gene gain, non-amplified gene increases (TOP1/CEN-2≥1.5 and TOP1/CEN-20<2.0) showed a trend towards shorter TTR (univariate HR: 1.57, p = 0.07).

CONCLUSIONS

TOP1 gene copy number increase occurs frequently in stage III CRC in a mechanism that often includes CEN-20. Using CEN-2 as a measurement for tumor ploidy levels, we were able to discriminate between different mechanisms of gene gain, which appeared to differ in prognostic impact. TOP1 FISH guidelines have been updated.

Evaluation of the prognostic role of centromere 17 gain and HER2/topoisomerase II alpha gene status and protein expression in patients with breast cancer treated with anthracycline-containing adjuvant chemotherapy: pooled analysis of two Hellenic Cooperative Oncology Group (HeCOG) phase III trials

BACKGROUND

The HER2 gene has been established as a valid biological marker for the treatment of breast cancer patients with trastuzumab and probably other agents, such as paclitaxel and anthracyclines. The TOP2A gene has been associated with response to anthracyclines. Limited information exists on the relationship of HER2/TOP2A gene status in the presence of centromere 17 (CEP17) gain with outcome of patients treated with anthracycline-containing adjuvant chemotherapy.

METHODS

Formalin-fixed paraffin-embedded tumor tissue samples from 1031 patients with high-risk operable breast cancer, enrolled in two consecutive phase III trials, were assessed in a central laboratory by fluorescence in situ hybridization for HER2/TOP2A gene amplification and CEP17 gain (CEP17 probe). Amplification of HER2 and TOP2A were defined as a gene/CEP17 ratio of >2.2 and ≥2.0, respectively, or gene copy number higher than 6. Additionally, HER2, TopoIIa, ER/PgR and Ki67 protein expression was assessed by immunohistochemistry (IHC) and patients were classified according to their IHC phenotype. Treatment consisted of epirubicin-based adjuvant chemotherapy followed by hormonal therapy and radiation, as indicated.

RESULTS

HER2 amplification was found in 23.7% of the patients and TOP2A amplification in 10.1%. In total, 41.8% of HER2-amplified tumors demonstrated TOP2A co-amplification. The median (range) of HER2, TOP2A and CEP17 gain was 2.55 (0.70-45.15), 2.20 (0.70-26.15) and 2.00 (0.70-26.55), respectively. Forty percent of the tumors had CEP17 gain (51% of those with HER2 amplification). Adjusting for treatment groups in the Cox model, HER2 amplification, TOP2A amplification, CEP17 gain and HER2/TOP2A co-amplification were not associated with time to relapse or time to death.

CONCLUSION

HER2 amplification, TOP2A amplification, CEP17 gain and HER2/TOP2A co-amplification were not associated with outcome in high-risk breast cancer patients treated with anthracycline-based adjuvant chemotherapy.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12611000506998 and ACTRN12609001036202.

Topoisomerase 1(TOP1) gene copy number in stage III colorectal cancer patients and its relation to prognosis

PURPOSE

A Topoisomerase 1 (Top1) poison is frequently included in the treatment regimens for metastatic colorectal cancer (mCRC). However, no predictive biomarkers for Top1 poisons are available. We here report a study on the TOP1 gene copy number in CRC patients and its association with patient prognosis and tumor cell proliferation.

EXPERIMENTAL DESIGN

The study included TOP1 and CEN-20 fluorescence in situ hybridization (FISH) analyses on formalin fixed paraffin embedded (FFPE) tissue sections from 154 stage III CRC chemonaïve patients. The frequencies of aberration in the TOP1 gene copy number, the CEN-20 copy number and the TOP1/CEN-20 ratio were analyzed and associated with overall survival (OS), time to recurrence (TTR) and in a subgroup analysis of rectal cancer patients only with time to local recurrence (LR in RC). Moreover, the TOP1 and CEN-20 copy numbers were correlated with the tumor Ki67 proliferation index.

RESULTS

35.7% of the tumors had an increased TOP1 copy number above 4n gene copies per cell and 28.6% and 9.7% had a TOP1/CEN-20 ratio ≥1.5 or ≥2.0, respectively. The TOP1 copy number and the TOP1/CEN-20 ratios were separately added into multivariate analyses as continuous variables, in which also age, gender, primary tumor location and Ki67 status were added as covariates. In contrast to the TOP1/CEN-20 ratio, the TOP1 copy number was significantly associated with OS (HR: 0.62; 95% CI: 0.42-0.90; p = 0.01). Neither the TOP1 copy number nor the ratio was significantly associated with TTR and only the TOP1/CEN-20 ratio was significantly associated with LR in RC (HR: 0.25; 95% CI: 0.08-0.83; p = 0.02). No significant correlation was found between the TOP1 copy number and proliferation, while a weak and inverse correlation between the CEN-20 copy number and proliferation was observed.

CONCLUSIONS

This study showed that increased TOP1 gene copy numbers are frequent findings in cancer cells in stage III CRC tumors but unrelated to the proliferative status of the tumors. The association with prognosis is important to consider when planning and analyzing future studies investigating TOP1 as a potential predictive biomarker for Top1 poisons.

ESR1 gene status correlates with estrogen receptor protein levels measured by ligand binding assay and immunohistochemistry

The Estrogen Receptor (ER) is an established predictive marker for the selection of adjuvant endocrine treatment in early breast cancer. During the 1990s Immunohistochemistry (IHC) replaced cytosol based assays for determination of ER status. This study examined the association between ER protein level determined by two different methods and ESR1 gene copy number. From 289 primary high-risk breast cancer patients, randomized in the Danish Breast Cancer Cooperative Group (DBCG) 77C trial, results from cytosolic ER levels were available from ligand binding assays. Archival tumor tissue was retrieved from 257 patients. ESR1/CEN-6 ratio was analyzed successfully by Fluorescence In Situ Hybridization (FISH) in 220 (86%) patients. ESR1 amplification (ESR1/CEN-6 ≥ 2.00) was observed in 23% of the patients and ESR1 deletion (ESR1/CEN-6 < 0.80) was observed in 32%. Further, we identified ESR1 gain (ratio ESR1/CEN-6 from 1.30 to 1.99) in 19% of the patients. A positive correlation of ESR1 FISH with both ER-cytosol and ER IHC was found (p < 0.0001). Amplification and gain of the ESR1 gene are associated with higher ER protein content measured by ligand binding assay and a more intense nuclear staining by IHC compared to tumors with normal ESR1 gene status. Major variations in ER measured by ligand binding assay and IHC are observed within all ESR1 copy number subgroups and other mechanisms than gene copy number seem to contribute to the ER protein content in the tumors.

Lack of independent prognostic and predictive value of centromere 17 copy number changes in breast cancer patients with known HER2 and TOP2A status

The clinical benefit of anthracyclines has been connected to HER2 status, TOP2A status and centromere 17 copy numbers (CEN-17). Data from a clinical trial randomizing patients to anthracyclines was used to assess whether the number of CEN-17 in breast cancers may predict incremental responsiveness to anthracyclines besides what is obtained when used relatively to TOP2A and HER2. As cut sections of paraffin-embedded tissue are prone to truncation of nuclei, strict definition of ploidy levels is lacking. We therefore used normal breast tissue to assist define ploidy levels in cut sections. Fluorescence in situ hybridization (FISH) with centromere 17 (CEN-17) and TOP2A was performed on 120 normal breast specimens. The diploid CEN-17 copy number was reduced from the expected two signals in whole nuclei to an average of 1.68 signals per nucleus in cut sections of normal breast. Ploidy levels determined in normal breast were applied to data on 767 patients with known HER2 and TOP2A status randomized to anthracyclines in the DBCG 89D trial. CEN-17 ploidy levels were in cut sections from the 767 breast cancer patients established as: Haploid: ≤1.25 (10%), diploid: 1.26-2.09 (60%), triploid: 2.10-2.93 (21%), tetraploid: 2.94-3.77 (5%) or higher ploidy: ≥3.78 (4%). Amplification of HER2 and deletion of TOP2A were frequently observed in tumors with a high ploidy level. In univariate analyses increasing ploidy was associated with decreased disease-free survival (DFS) (P=0.0001) and overall survival (OS) (P<0.0001). However, in multivariate analysis CEN-17 was not established as an independent prognostic factor and was neither a statistically significant predictor of benefit from CEF (Cyclophosphamide/Epirubicin/5-Fluorouracil) compared to CMF (Cyclophosphamide/Methotrexate/5-Fluorouracil) (P(Interaction) 0.39 for DFS and 0.67 for OS). In conclusion, CEN-17 levels do not independently from TOP2A/CEN-17 ratio identify breast cancer patients who achieve an incremental benefit from adjuvant anthracyclines.