Abstract P6-09-16: Identification of proliferation related derivers and their roles in precision medicine for breast cancers: A retrospective multidimensional comparative, integrated genomic, transcriptomic, and protein analysis

Backgound and Aim: The best test to guide the choice of systemic therapy for breast cancer (BC) has not yet been identified. We did this study to identify factors that drive proliferation features in BC and assess their association with clinical outcomes after systemic therapy.

Methods: We applied an artificial neural network-based integrative data mining approach to three cohorts of patients with untreated lymph node (LN)-negative BC (Wang et al; n=286, Desmedt et al; n=198 and Schmidt et al; n=200). The results were validated in four cohorts of BC patients (the Nottingham discovery cohort (n=171), Uppsala cohort (n=249), The Cancer Genome Atlas-Breast Cancer project [TCGA-BRCA; n= 970] and Molecular Taxonomy of Breast Cancer International Consortium [METABRIC cohort; n=1980]. Genes that featured prominently in our interactome map of proliferation have been chosen to take them forward to investigate their clinicopathological relevance of their gene copy number aberrations (CNAs), mRNA transcript expression, and protein expression and their associations with breast cancer-specific survival (BCSS), distant relapse-free survival (DRFS) and pathological complete response (pCR) in ten international cohorts of BC (n>12000 patients).

Findings: ESR1, SPAG5, EGFR, BCL2, and FOXA1 were among the 39 common gene probes that were predictive across most proliferation features and datasets. In TCGA-BRCA cohort, SPAG5 gene mutation, gain/amplification and loss at the Ch17q11.2 locus were detected in 43 (4.4%), 177 (18.2%) and 180 (18.8%) of 970 patients, respectively and 65 (31%) of 479 ER-positive /HER-positive patients showed gain/amplification of SPAG5 gene. In multivariable analysis, high SPAG5 transcript and SPAG5 protein expression were associated with reduced BCSS compared with lower expression (METABRIC: HR 1·27, 95% CI 1·02–1·58, p=0·034; untreated LN-negative cohort: 2·34, 1·24–4·42, p=0·0090; and Nottingham-cohort: 1·73, 1·23–2·46, p=0·0020). In patients with ER-negative/HER2-negative or ER-positive/HER2-negative BC, high SPAG5 transcript expression was associated with an increased pCR compared with low SPAG5 transcript expression after receiving anthracycline neoadjuvant chemotherapy (AC-NeoACT) [(Multicentre phase 2 clinical trial cohort; n=136; OR 2·47, 95% CI 1·17–5·21, p=0.016) and (MD Anderson- taxane+AC-NeoACT cohort; n=287; OR 3·16, 95% CI 1·46–6·84, p=0.003); respectively]. In patients with ER-positive/HER2-negative BC who received taxane+AC-NeoACT followed by adjuvant tamoxifen (Adj-Tam) for 5 years (MD Anderson- taxane+AC-NeoACT cohort; n=287), high and low SPAG5 transcript expression had similar DRFS (HR 1·40, 95% CI 0.76–2·58, p=0.282). Whereas in ER-positive/HER2-negative BC patients who received only adj-Tam (n=298), high SPAG5 transcript expression was associated with reduced DRF at 5 years compared with lower expression (HR 1.98, 95% CI 1.19–3.27, p=0.008).

Interpretation: The transcript and protein products of SPAG5 are independent prognostic and predictive biomarkers that might have clinical utility as biomarkers for combination cytotoxic chemotherapy sensitivity in ER-positive/HER-negative BC.

Citation Format: Abdel-Fatah TMA, Agarwal D, Zafeiris D, Pongor L, Györffy B, Rueda OM, Moseley PM, Green AR, Liu D-X, Pockley AG, Rees RC, Caldas C, Ellis IO, Ball GR, Chan SYT. Identification of proliferation related derivers and their roles in precision medicine for breast cancers: A retrospective multidimensional comparative, integrated genomic, transcriptomic, and protein analysis [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-16.

Abstract P5-08-17: A study of c-Jun N-terminal kinase (JNK) and c-Jun as biomarkers in early breast cancer

Background

The AP-1 transcription factor c-Jun is a key downstream target of c-Jun N-terminal kinase (JNK) which mediates intracellular signalling associated with a variety of cellular functions. The JNK pathway in breast cancer (BC) can be attenuated via loss of function mutations in MAPK kinases as well as via PIK3CA mutations; however, there is contradictory information about the role of JNK pathway and its clinical implications in BC.

Methods

In the current study, the clinicopathological implications of JNK and JUN mRNA expressions were evaluated in multiple independent BC datasets: a) Training-set (Uppsala cohort; n=249), b) Test-set (human genome atlas database; n=540), c) External validation-set (METABRIC cohort; n=1952) and d) Multicentre pooled databases (n=5530). The clinicopathological associations of their phosphorylated proteins (p-Jnk and p-c-Jun) were assessed in the Nottingham Tenovus Primary BC Series (n= 1650) and in an ER negative cohort (n=450).

Results

Both JNK and c-JUN mRNA high expressions were significantly associated with PAM50-Luminal A and ER+/HER2-/low proliferation molecular BC subtypes, tubular/lobular types, and integrative molecular clusters 4 (IntClust.4), ps<0.001. Whereas BC that had both low JNK and c-JUN mRNA, were significantly associated with large tumour size, high grade, absence of hormonal receptors (HR), HER2 overexpression, PAM50 HER2 and PAM50 Basal molecular subtypes, and IntClust.1, 9 and 10 BCs; ps<0.001.

There was a significant positive correlations between p-Jnk and p-c-Jun protein levels (p<0.0001), however; our data suggested that differential p-Jnk/p-c-Jun expression may influence BC phenotypes. BC with p-Jnk-ve/p-c-Jun-ve were associated with the most aggressive phenotypes including largest tumour size, highest grade, lympho-vascular invasion, absence of HR, basal-like-phenotype, HER2 overexpression, and loss of double strand , single stand and base excision DNA repair proteins (ps<0.0001). In addition p-Jnk-ve/ pc-Jun-ve phenotype was associated with the lowest levels of p-38, ATF2, and p-ATF2; ps<0.001. Interestingly, low levels of either c-JUN-mRNA or pc-Jun protein, was associated with, PAM50-luminal B, epithelial mesenchymal transition and TP53 mutation and loss of its downstream proteins such as MDM2, MDM4, Bcle2 and p21; ps<0.05.

JNK+ (mRNA and p-Jnk) and c-JUN+ (mRNA and p-c-Jun) individually were associated with prolonged BC specific survival (ps<0.001). Multivariate cox regression models that included other validated prognostic factors and therapies revealed that c-JUN-mRNA (Uppsala: p=0.005 and METABIRIC: p=0.036) and p-c-Jun (HR: 0.69; 95% CI = 0.55-0.88; p=0.002) were independently associated with clinical outcome. Furthermore, in ER+ high risk BC, exposure to tamoxifen was associated with decreased risk of death from BC in those patients with p-c-Jun-ve BC (HR: 0.65; 95% CI: 0.45-0.95; p=0.025).

Conclusion

JNK and c-JUN mRNA as well as p-Jnk and p-c-Jun protein levels are associated with luminal BC, with p-c-Jun being found to be an independent prognostic factor. The interaction between p-Jnk, p-c-Jun and TP53 mutation could predict response to endocrine therapy in ER+ BC. The role of the transcriptionally active form of c-JUN warrants further investigation with regard to its role in BC.

Citation Format: Palmieri C, Rudraraju B, Giannoudis A, Moore D, Shaw J, Chan S, Ellis IO, Caldas C, Coombes RC, Carroll JS, Ali S, Abdel-Fatah TMA. A study of c-Jun N-terminal kinase (JNK) and c-Jun as biomarkers in early breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-17.

Molecular profiling of breast cancer in Nigerian women identifies an altered p53 pathway as a major mechanism underlying its poor prognosis compared with British counterpart

BACKGROUND

Advances in breast cancer (BC) research have demonstrated differences between black and white women with regarding tumour behaviour, patient outcome and response to treatment which can be explained by underlying genetic changes. The tumour suppressor gene p53 has been speculated to be involved in tumour biology of triple negative and/or basal -like BC and more commonly observed in black than caucasian women.

MATERIALS AND METHODS

In this study, the protein expression of p53 was investigated in tissue samples from a series of 308 Nigerian women, prepared as a tissue microarray (TMA), using immunohistochemistry. Clinicopathological parameters, biomarkers of functional significance in BC and patient outcome of tumours expressing p53 in Nigerian women were correlated with UK grade matched series.

RESULTS

A significantly large proportion of BC from Nigerian women showed high p53 expression compared with UK women (p<0.001). In those tumours showing positive p53 in the Nigerian series, a significant proportion were premenopausal, diagnosed before 50 years, larger in size, with evidence of metastasis into lymphatic vessels ( all p<0.001). In addition, p53 positive expression was also significantly correlated with negative expression of ER and PgR (p<0.001, p<0.03 respectively), BRCA1, MDM2 (all p<0.001), p21 (p=0.006) and E-cadherin (p=0.001) and positively associated with P-cadherin (p=0.001), triple negative phenotype, basal cytokeratin (CK) 5/6 expression (p<0.04) and basal phenotype compared with the UK series (p<0.001). Survival analyses showed Nigerian women with BC were significantly associated with poor BC specific survival (p<0.001, but no significant association with disease free interval was observed.

CONCLUSION

In this study, protein expressions of p53 pathways are different between Nigerian and UK BC women and this may also contribute to differences in tumour biology. Therefore, targeting these p53 pathways for therapeutic usage might improve the poor outcome observed in Black Nigerian women.

Bcl2 is an independent prognostic marker of triple negative breast cancer (TNBC) and predicts response to anthracycline combination (ATC) chemotherapy (CT) in adjuvant and neoadjuvant settings

BACKGROUND

TNBC represents a heterogeneous subgroup of BC with poor prognosis and frequently resistant to CT.

MATERIAL AND METHODS

The relationship between Bcl2 immunohistochemical protein expression and clinico-pathological outcomes was assessed in 736 TNBC-patients: 635 patients had early primary-TNBC (EP-TNBC) and 101 had primary locally advanced (PLA)-TNBC treated with neo-adjuvant- ATC-CT.

RESULTS

Negative Bcl2 (Bcl2-) was observed in 70% of EP-TNBC and was significantly associated with high proliferation, high levels of P-Cadherin, E-Cadherin and HER3 (P's < 0.01), while Bcl2+ was significantly associated with high levels of p27, MDM4 and SPAG5 (P < 0.01). After controlling for chemotherapy and other prognostic factors, Bcl2- was associated with 2-fold increased risk of death (P = 0.006) and recurrence (P = 0.0004). Furthermore, the prognosis of EP-TNBC/Bcl2- patients had improved both BC-specific survival (P = 0.002) and disease-free survival (P = 0.003), if they received adjuvant-ATC-CT. Moreover, Bcl2- expression was an independent predictor of pathological complete response of primary locally advanced triple negative breast cancer (PLA-TNBC) treated with neoadjuvant-ATC-CT (P = 0.008).

CONCLUSION

Adding Bcl2 to the panel of markers used in current clinical practice could provide both prognostic and predictive information in TNBC. TNBC/Bcl2- patients appear to benefit from ATC-CT, whereas Bcl2+ TNBC seems to be resistant to ATC-CT and may benefit from a trial of different type of chemotherapy with/without novel-targeted agents.

Abstract P6-07-09: Identification of Trophinin associated protein (TROAP) as a novel biological marker in breast cancer (BC): Co-expression of TROAP and TOPO2A predicts response of anthracycline based chemotherapy (ATC-CT)

Introduction: Recently, TOPO2A alteration was found to be a predictor for ATC-CT and by using neural network and pathways analysis of gene expression array data, TROAP gene was revealed as a major hub in TOPO2A pathway and strongly related to genes that are involved in mitotic cell cycle regulation. In addition, we found that TROAP gene was among top 10 ranked genes out of 48,000 of transcripts, that accurately predicted worse clinical outcome, and differentiated between low and high grade based on a 10-fold external cross-validation analysis with an average classification accuracy of &gt;99.999%. TROAP protein is essential for centrosome integrity and proper bipolar organisation of spindle assembly during mitosis and plays essential role in cell proliferation.

In the current study the molecular and clinicopathological functions of TROAP expression and its effect on management of breast cancer have been investigated.

Methods: The co-expression of TROAP and TOPO2A protein was evaluated by using dual immunoflurescent in BC cell lines. In addition both TROAP and TOP2A protein expressions were immunohistochemically (IHC) assessed in 40 normal breast tissues and a well characterised series of 1650 primary BC and were correlated to clinicopathological and other biomarkers. IHC staining was performed using Anti-TROAP rabbit polyclonal (HPA044102; Sigma).

The association between TROAP and response to chemotherapy was investigated in 350 ER negative BC treated with adjuvant ATC-CT and 260 locally advanced BC treated with neoadjuvant ATC-CT. In addition the clinical outcome of TROAP expression was evaluated in a series of 180 ER− high risk BC patients who did not received any CT.

Results: No expression of TROAP protein was observed in normal breast tissue while, 25% of BC showed TROAP protein overexpression. By using dual immunoflurescent in BC cell lines, The MCF7 cells showed strong cytoplasmic TROAP staining with no TOPO2A expression, while The T47D cells did not express TROAP but expressed TOPO2A. SKBr3, MDA468 and MDA231 cell lines showed co-expression of TROAP and TOPO2A. TROAP overexpression was significantly associated with aggressive clinico-pathological features including; high grade, high mitotic rate, absence of hormonal receptors, overexpression of HER2, TOP2A and EGFR (p &lt; 0.001), Triple negative phenotype (p &lt; 0.001), basal-like BC (p &lt; 0.001), p53 mutation (p &lt; 0.001) and inactive p16 (p &lt; 0.001). With regard to outcome, receiving anthracycline chemotherapy had a positive impact on high risk ER− BC patients with TROAP protein over-expression as TROAP protein overexpression showed 50% less risk of recurrence compared to TROAP negative expression; p &lt; 0.0001. Moreover, in locally advanced BC who received anthracycline-based neoadjuvant chemotherapy, 31/81 (39%) of BC with co-expression of TROAP+/TOPO2A+ achieved pCR while none of those with absence of both TROAP−/TOPO2A− (0/51) had achieved pCR (p &lt; 0.00001).

Conclusion: TROAP is an important novel gene implicated in the survival of BC cells and its protein expression is a predictor for Anthracycline CT. TROAP may provide new avenues for the discovery of new predictive marker to guide therapeutic intervention.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-09.

Abstract P2-10-22: Phosphorylation of Steroid Receptor Coactivator 3 (SRC3) at Ser543 is a novel independent prognostic marker in breast cancer

Introduction: Steroid receptor coactivator 3 (SRC3) acts as a coactivator of nuclear receptors including estrogen receptor-alpha (ER). SRC3 has been implicated in the pathogenesis of breast cancer (BC) as well as in resistance to endocrine therapy. SRC3 is phosphorylated at a number of residues following the stimulation of growth factors or hormones. Tyr24 and Ser543 are both phosphorylated upon estrogen stimulation, while Tyr24 is modulated by JNK and Ser543 by both p38 and JNK. To date, the importance and potential role of phosphorylation at these residues has not been explored in BC. In this study we assessed the protein expression of SRC3, pTyr24 and pSer543 and association with clinico-pathological features and outcome in a well defined breast cancer series.

Methods: The expressions of SRC3, pTyr24 and pSer543 were assessed in the Nottingham Tenovus Primary Breast Cancer Series which consists of 1650 cases of primary invasive. SRC3, pTyr24 and pSer543 were correlated with clinico-pathological data as well as outcome.

Results: SRC3 expression was significantly associated with unfavourable clinicopathological features including ER -ve (p = 0.02), PR –ve (p = .038), HER2 overexpression (p &lt; 0.0001), Triple negative phenotype (p = 0.001), high proliferation (p &lt; 0.0001), high histological grade (p &lt; 0.001), and lympho-vascular invasion. On contrast, the expression of pSer543 was significantly associated with a luminal phenotype, well differentiation, low proliferation (low mitotic index, low Ki67 and low SPAG5; p &lt; 0.0001), hormonal receptors (ERα+ve/PR+ve/AR+ve), absence of both ER-B1 and ER-B5 (p &lt; 0.01), high expression of ER-α associated proteins (cyclin D1 and Bcl2; p &lt; 0.0001), high expression of c-jun (p &lt; 0.0001), JNK (p &lt; 0.0001), SRC3 (p &lt; 0.0001), T24 (p &lt; 0.001) and active p53 transcriptional pathways that regulate cell cycle progression and apoptosis (MDM2+ve, MDM4+ve and Bax+ve; p &lt; 0.01) and absence of basal like phenotypes (p &lt; 0.01). The absence of pSer543 was significantly associated with loss of expression of the key DNA repair proteins including XRCC1 (p &lt; 0.0001), BRCA1 (p &lt; 0.0001), ATM (p = 0.008) and TOP2A (p &lt; 0.0001) reflecting a higher risk of genomic instability. Moreover, absence of pSer543 was more common in BC with a triple negative phenotype (p &lt; 0.001). With regard to outcome, no association with outcome based on the expression of SRC3 either with or without tamoxifen was observed. However, expression of pSer543 was associated with significantly longer disease free survival (DFS) (p &lt; 0.00001) and breast cancer specific survival (BCSS) (p = 0.0001). Furthermore, absence of pSer543 was associated with both a shorter DFS (p = 0.007) and BCSS (p = 0.01) in ER+ ve high risk BC. pSer534 was confirmed as an independent prognostic factor after adjustment for endocrine therapy and other validated prognostic factors and absent of pSer534 was associated with a two-fold increased risk of recurrence (HR = 1.9, CI 95%= 1.2–3.1). Data on Tyr24 will also be presented.

Conclusion: Phosphorylation at Ser543 is associated with a luminal phenotype, positive prognostic factors and sensitivity to tamoxifen. Furthermore, it is an independent prognostic factor. pS543 is a novel prognostic marker in BC and warrants further investigation.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-22.

Abstract P6-07-18: Identification of Sperm Associated Antigen 5 (SPAG5) as a novel biological and predictive biomarker in Breast cancer

Introduction: SPAG5 has been found to be involved in the functional and dynamic regulation of mitotic spindles, and to be essential for chromosome segregation fidelity. Recently we found by using neural network and pathways analysis of a gene expression array data that SPAG5 was among top 10 ranked genes out of 48,000 of transcripts, that accurately predicted worse clinical outcome based on a 10-fold external cross-validation analysis with an average classification accuracy of &gt;99.999%. Moreover we found that 5% of BC showed amplification of SPAG5 locus at chromosome 17q11.2 and SPAG5 mRNA expression levels displayed a statistically significant correlation with its copy number.

Methods: In the current study the molecular and clinicopathological features of SPAG5 expression and its effect on management of BC have been investigated in 2800 BC patients with primary operable invasive BCs constituted four cohorts: 1) A series of 1650 BC patients received adjuvant endocrine and/or CMF chemotherapy according to NPI.2) A series of 256 BC received adjuvant anthracycline-based chemotherapy (ATC-CT)3) A series of 140 primary BC HER2+ patients treated with ATC-CT+ Herceptin 4) To validate SPAG5 as a predictor factor for ATC-CT, 260 patients with locally advanced primary breast cancer treated with neoadjuvant ATC-CT were included and the pathological complete response (pCR) was used to evaluate the response to chemotherapy.

Immunohistochemical staining was performed using Anti–SPAG5 rabbit polyclonal (HPA022479; Sigma).

Results: i) By using dual immunoflurescent in BC cell lines, co-expression of SPAG5 and proliferating cell nuclear antigen (PCNA) was detected in 4 out of 5 of the breast cancer cell lines screened (MCF7, T47D, MDA468 and MDA231) providing evidence for the importance of SPAG5 in cell proliferation. ii) 20% of breast cancer showed SPAG5 protein overexpression. SPAG5 overexpression showed a statistically significant association with ER−, PR−, triple negative phenotype, high grade tumour, high ki67, basal like phenotype and epithelial mesenchymal transition phenotype, p53 mutation and absence of DNA repair genes (BRCA1, ATM and XRCC1); p values &lt;0.0001. iii) In high risk ER− BC patients who did not received any adjuvant therapy or received ineffective CMF chemotherapy, SPAG5+ protein expression had a similar risk of death and recurrence. Receiving ATC-CT had a positive impact on high risk ER− BC patients with SPAG5 protein + expression as SPAG5+ protein expression showed 72–65% less of death, recurrence and metastases compared to SPAG5−; p &lt; 0.0001. The positive impact of ATC-CT on SPAG5+BC has also been confirmed in HER2+ who either received ATC-CT only or ACT-CT plus Herceptin. iv) Moreover, BC received neoadjuvantATC-CT, SPAG5+ BC achieved 39% pCR vs., 6% of SPAG5-negative BC (p &lt; 0.00001). After controlling to other validated predictors for pCR, SPAG5 remained as a powerful independent predictor (HR; 2.4, CI 95%; 1.5–3.9; p = 0.00001).

Conclusion: SPAG5 is an important novel gene implicated in the survival of BC cells and its protein expression is an independent predictor for ATC- CT. SPAG5 may provide new avenues for the discovery of new predictive marker to guide therapeutic intervention.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-18.

P4-09-11: Kinesin Family Member 2C (KIF2C) Is a New Surrogate Prognostic Marker in Breast Cancer (BC)

Introduction

Gene expression microarrays, artificial neural network (ANN), tissue microarray and immunohistochemistry (IHC) techniques allow for the analysis of huge numbers of gene transcripts and their corresponding proteins and have been widely applied in predicting clinical outcome.

Methods

1- In this study, we analysed 48,000 gene transcripts of 171 unselected series of BC using ANN and pathways analysis to identify genes that can be used to predict clinical outcome of BC.

2- The clinic-pathological outcome of candidate genes were validated by using IHC in 4 independent primary BC data sets: a) a series of 379 consecutive high risk BC (NPI&gt;3.4) who treated with surgery (S)+ radiotherapy (RT) and did not received neither endocrine (ET) nor chemo-therapies (CT), b) A series of 1650 consecutive cases of BC who treated with S + RT and received adjuvant CMF and/or ET according to Nottingham prognostic index (NPI), menopausal and ER status, c) 250 locally advanced BC treated with anthracycline-based combination with or without Taxane followed by S + RT and d) 145 BC overexpressing HER-2 treated with S + RT followed by sequential adjuvant anthracycline combination CT + trastuzumab.

Results

Gene expression analysis

ANN analysis revealed that KIF2C gene was the highest ranked gene that predicted clinical outcome and accurately differentiated between low and high grade BC based on a 10-fold external cross-validation analysis with an average classification accuracy of &gt;98%. High KIF2C gene expression level was associated with shortest BC specific survival (BCSS), disease free (DFS) and distal metastasis free survivals (DM-FS); p&lt;0.0001. In univariate analysis, high level of KIF2C gene expression was associated with large tumour size, higher lymph node stage, negative ER, positive p53 expression and HER2 overexpression. However in multivariate analysis, KIF2C gene expression level was only statistically associated with histological grade (p&lt;00001) and mitosis (p&lt;0.0001). Pathways analysis revealed that KIF2C is likely to play a significant role in cytokinesis, cell division and cell cycle regulations.

Immunohistochemistry

75% of BC showed overexpression of KIF2C protein. KIF2C protein overexpression was associated with unfavourable clinic-pathological features including high grade, high mitotic index, basal like phenotype, triple negative phenotype, HER2 overexpression, TOP2A overexpression, p53 mutation, and loss of BRCA1 (adjusted p&lt;0.0001).

In univariate analysis, KIF2C protein overexpression was associated with patient's BCSS in both ER+/high risk patients (NPI &gt; 3.4) who did not received ET (HR: 3.3, 95% CI: 1.2−9.3, p=0.02) and ER-/high risk patients who did not received CT (HR: 3.2, 95% CI: 1.1−8.8, p=0.025).

In 1650 BC series, multivariate Cox regression model including validated prognostic factors, confirmed that KIF2C overexpression is an independent prognostic factor. KIF2C overexpression showed increase in the risk of death (HR: 1.5, 95% CI: 1.1−2.0, p=0.009), recurrence (HR: 1.4, 95% CI: 1.1−1.8, p=0.017) and DM (HR: 1.6, 95% CI: 1.2−2.3, p=0.005).

In conclusion, our findings provide a new insight to a better understanding of mammary carcinogenesis and that KIF2C is a promising molecular prognostic factor and a potential therapeutic target.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-09-11.

P1-06-14: Topoisomerase II alpha (Top2a) Protein Expression Is a Predictor for Response to Anthracycline-Based Chemotherapy (ATC-CT): Is It Due to Gene Amplification, HER2−Coamplification or a Summation of Pathways Leading to This Highly Proliferative Phenotype?

Background: The evaluation of Top2a protein may be clinically more useful than gene alterations as a predictive marker for ATC-CT. In this study we assessed the association between gene copy number, gene and protein expressions of both TOP2A and HER2, and their effect on clinicopathological outcomes and management of breast cancer (BC).

Methods: 1- To study the response to anthracycline based chemotherapy (ATC-CT): The associations between clinical outcomes and both gene copy number changes (using in-situ hybridization; CISH) and protein expression (using immunohistochemistry) were studied in the neoadjuvant and adjuvant settings: a) 250 locally advanced primary BC treated with Neoadjuvant ATC-CT with or without Taxane followed by surgery (S) + radiotherapy (RT); pathological complete response (pCR) was used as the primary end point (PEP), b) 245 BC in which all patients were treated with S + RT followed by Adjuvant ATC-CT; progression free survival (PFS) was used as PEP ii) 145 primary BC overexpressing HER-2 treated with S+ RT followed by sequential adjuvant ATC-CT+ trastuzumab; PFS was used as PEP. 2- To study the clinic-pathological association of TOP2A alterations, we evaluated TOP2A alterations detected by CISH and IHC in unselected series of 1650 consecutive cases of primary BC who treated with S + RT and received adjuvant CMF and/or endocrine therapies according to Nottingham prognostic index and ER status. 3- To study in details the molecular alterations of TOP2A/HER2, in 171 unselected series of primary BC, we evaluated a) gene copy number changes using both high resolution oligo array CGH and CISH, b) mRNA expression using Agilent gene expression array and c) protein expression using IHC. We analysed 48,000 gene transcripts using Artificial Neural Networks (ANN) and pathway analysis to identify genes and biological pathways that related to TOP2A gene alterations.

Results: 1) In the ATC-CT neoadjuvant series, the pCR rate was 32/115 (28%) in tumours expressing high levels of Topo2A, compared to 5/74 (7%) in tumours expressing low levels of Topo2A (p&lt;0.0001).

In multivariate analysis, Top2A overexpression was an independent predictor for pCR (HR 5.1, CI 95%; 1.4−18.4, p&lt;0.001). 2) TOP2A overexpression was strongly associated with mitotic index, histological grade, KIF2C, loss of p53 function and the absence of both BRCA1 and ATM inactivation (p&lt;0.0001). 3) ANN and pathway analysis revealed that TOP2A-strongly correlated genes are involved in: mitotic cell cycle regulation especially M phase and cell division (AURKB, KIF2C, BRIC5, ASPM, CCNA2, BUB1, FBXO5, PTTG1, CDCA5, CDCA3 CDCA8), Kinesin and microtubules regulator genes (KIF2C, KIF11, KIF14, KIF20A, KIF23, and KIFC1), and metastases (BRIC5, BUB1B, CCNA2, CCNE, PRRG1, PRM2, STMN1). Conclusions: Top2A protein expression is an independent predictor for pCR after ATC-CT treatment. The high response rate of top2A protein overexpression supports the theory that Top2a protein is a direct target of ATC-CT in these highly proliferative tumour cells. Furthermore, evaluation of Top2A protein may lead to a clinically useful test.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-06-14.