Association of Sperm-Associated Antigen 5 and Treatment Response in Patients With Estrogen Receptor-Positive Breast Cancer

Importance

There is no proven test that can guide the optimal treatment, either endocrine therapy or chemotherapy, for estrogen receptor-positive breast cancer.

Objective

To investigate the associations of sperm-associated antigen 5 (SPAG5) transcript and SPAG5 protein expressions with treatment response in systemic therapy for estrogen receptor-positive breast cancer.

Design, Settings, and Participants

This retrospective cohort study included patients with estrogen receptor-positive breast cancer who received 5 years of adjuvant endocrine therapy with or without neoadjuvant anthracycline-based combination chemotherapy (NACT) derived from 11 cohorts from December 1, 1986, to November 28, 2019. The associations of SPAG5 transcript and SPAG5 protein expression with pathological complete response to NACT were evaluated, as was the association of SPAG5 mRNA expression with response to neoadjuvant endocrine therapy. The associations of distal relapse-free survival with SPAG5 transcript or SPAG5 protein expressions were analyzed. Data were analyzed from September 9, 2015, to November 28, 2019.

Main Outcomes and Measures

The primary outcomes were breast cancer-specific survival, distal relapse-free survival, pathological complete response, and clinical response. Outcomes were examined using Kaplan-Meier, multivariable logistic, and Cox regression models.

Results

This study included 12 720 women aged 24 to 78 years (mean [SD] age, 58.46 [12.45] years) with estrogen receptor-positive breast cancer, including 1073 women with SPAG5 transcript expression and 361 women with SPAG5 protein expression of locally advanced disease stage IIA through IIIC. Women with SPAG5 transcript and SPAG5 protein expressions achieved higher pathological complete response compared with those without SPAG5 transcript or SPAG5 protein expressions (transcript: odds ratio, 2.45 [95% CI, 1.71-3.51]; P < .001; protein: odds ratio, 7.32 [95% CI, 3.33-16.22]; P < .001). Adding adjuvant anthracycline chemotherapy to adjuvant endocrine therapy for SPAG5 mRNA expression in estrogen receptor-positive breast cancer was associated with prolonged 5-year distal relapse-free survival in patients without lymph node involvement (hazard ratio, 0.34 [95% CI, 0.14-0.87]; P = .03) and patients with lymph node involvement (hazard ratio, 0.35 [95% CI, 0.18-0.68]; P = .002) compared with receiving 5-year endocrine therapy alone. Mean (SD) SPAG5 transcript was found to be downregulated after 2 weeks of neoadjuvant endocrine therapy compared with pretreatment levels in 68 of 92 patients (74%) (0.23 [0.18] vs 0.34 [0.24]; P < .001).

Conclusions and Relevance

These findings suggest that SPAG5 transcript and SPAG5 protein expressions could be used to guide the optimal therapies for estrogen receptor-positive breast cancer. Retrospective and prospective clinical trials are warranted.

ERCC1 Is a Predictor of Anthracycline Resistance and Taxane Sensitivity in Early Stage or Locally Advanced Breast Cancers

Genomic instability could be a beneficial predictor for anthracycline or taxane chemotherapy. We interrogated 188 DNA repair genes in the METABRIC cohort (n = 1980) to identify genes that influence overall survival (OS). We then evaluated the clinicopathological significance of ERCC1 in early stage breast cancer (BC) (mRNA expression (n = 4640) and protein level, n = 1650 (test set), and n = 252 (validation)) and in locally advanced BC (LABC) (mRNA expression, test set (n = 2340) and validation (TOP clinical trial cohort, n = 120); and protein level (n = 120)). In the multivariate model, ERCC1 was independently associated with OS in the METABRIC cohort. In ER+ tumours, low ERCC1 transcript or protein level was associated with increased distant relapse risk (DRR). In ER−tumours, low ERCC1 transcript or protein level was linked to decreased DRR, especially in patients who received anthracycline chemotherapy. In LABC patients who received neoadjuvant anthracycline, low ERCC1 transcript was associated with higher pCR (pathological complete response) and decreased DRR. However, in patients with ER−tumours who received additional neoadjuvant taxane, high ERCC1 transcript was associated with a higher pCR and decreased DRR. High ERCC1 transcript was also linked to decreased DRR in ER+ LABC that received additional neoadjuvant taxane. ERCC1 based stratification is an attractive strategy for breast cancers.

SHON expression predicts response and relapse risk of breast cancer patients after anthracycline-based combination chemotherapy or tamoxifen treatment

Background

SHON nuclear expression (SHON-Nuc⁺) was previously reported to predict clinical outcomes to tamoxifen therapy in ERα⁺ breast cancer (BC). Herein we determined if SHON expression detected by specific monoclonal antibodies could provide a more accurate prediction and serve as a biomarker for anthracycline-based combination chemotherapy (ACT).

Methods

SHON expression was determined by immunohistochemistry in the Nottingham early-stage-BC cohort (n = 1,650) who, if eligible, received adjuvant tamoxifen; the Nottingham ERα⁻ early-stage-BC (n = 697) patients who received adjuvant ACT; and the Nottingham locally advanced-BC cohort who received pre-operative ACT with/without taxanes (Neo-ACT, n = 120) and if eligible, 5-year adjuvant tamoxifen treatment. Prognostic significance of SHON and its relationship with the clinical outcome of treatments were analysed.

Results

As previously reported, SHON-Nuc⁺ in high risk/ERα⁺ patients was significantly associated with a 48% death risk reduction after exclusive adjuvant tamoxifen treatment compared with SHON-Nuc⁻ [HR (95% CI) = 0.52 (0.34–0.78), p = 0.002]. Meanwhile, in ERα⁻ patients treated with adjuvant ACT, SHON cytoplasmic expression (SHON-Cyto⁺) was significantly associated with a 50% death risk reduction compared with SHON-Cyto⁻ [HR (95% CI) = 0.50 (0.34–0.73), p = 0.0003]. Moreover, in patients received Neo-ACT, SHON-Nuc⁻ or SHON-Cyto⁺ was associated with an increased pathological complete response (pCR) compared with SHON-Nuc⁺ [21 vs 4%; OR (95% CI) = 5.88 (1.28–27.03), p = 0.012], or SHON-Cyto⁻ [20.5 vs. 4.5%; OR (95% CI) = 5.43 (1.18–25.03), p = 0.017], respectively. After receiving Neo-ACT, patients with SHON-Nuc⁺ had a significantly lower distant relapse risk compared to those with SHON-Nuc⁻ [HR (95% CI) = 0.41 (0.19–0.87), p = 0.038], whereas SHON-Cyto⁺ patients had a significantly higher distant relapse risk compared to SHON-Cyto⁻ patients [HR (95% CI) = 4.63 (1.05–20.39), p = 0.043]. Furthermore, multivariate Cox regression analyses revealed that SHON-Cyto⁺ was independently associated with a higher risk of distant relapse after Neo-ACT and 5-year tamoxifen treatment [HR (95% CI) = 5.08 (1.13–44.52), p = 0.037]. The interaction term between ERα status and SHON-Nuc⁺ (p = 0.005), and between SHON-Nuc⁺ and tamoxifen therapy (p = 0.007), were both statistically significant.

Conclusion

SHON-Nuce⁺ in tumours predicts response to tamoxifen in ERα⁺ BC while SHON-Cyto⁺ predicts response to ACT.

Immune-Phenotyping and Transcriptomic Profiling of Peripheral Blood Mononuclear Cells From Patients With Breast Cancer: Identification of a 3 Gene Signature Which Predicts Relapse of Triple Negative Breast Cancer

Background: Interactions between the immune system and tumors are highly reciprocal in nature, leading to speculation that tumor recurrence or therapeutic resistance could be influenced or predicted by immune events that manifest locally, but can be detected systemically.

Methods: Multi-parameter flow cytometry was used to examine the percentage and phenotype of natural killer (NK) cells, myeloid-derived suppressor cells (MDSCs), monocyte subsets and regulatory T (Treg) cells in the peripheral blood of of 85 patients with breast cancer (50 of whom were assessed before and after one cycle of anthracycline-based chemotherapy), and 23 controls. Transcriptomic profiles of peripheral blood mononuclear cells (PBMCs) in 23 patients were generated using a NanoString gene profiling platform.

Results: An increased percentage of immunosuppressive cells such as granulocytic MDSCs, intermediate CD14⁺⁺CD16⁺ monocytes and CD127^negCD25^highFoxP3⁺ Treg cells was observed in patients with breast cancer, especially patients with stage 3 and 4 disease, regardless of ER status. Following neoadjuvant chemotherapy, B cell numbers decreased significantly, whereas monocyte numbers increased. Although chemotherapy had no effect on the percentage of Treg, MDSC and NK cells, the expression of inhibitory receptors CD85j, LIAR and NKG2A and activating receptors NKp30 and NKp44 on NK cells increased, concomitant with a decreased expression of NKp46 and DNAM-1 activating receptors. Transcriptomic profiling revealed a distinct group of 3 patients in the triple negative breast cancer (TNBC) cohort who expressed high levels of mRNA encoding genes predominantly involved in inflammation. The analysis of a large transcriptomic dataset derived from the tumors of patients with TNBC revealed that the expression of CD163, CXCR4, THBS1 predicted relapse-free survival.

Conclusions: The peripheral blood immunome of patients with breast cancer is influenced by the presence and stage of cancer, but not by molecular subtypes. Furthermore, immune profiling coupled with transcriptomic analyses of peripheral blood cells may identify patients with TNBC that are at risk of relapse after chemotherapy.

Evaluation of CDK12 Protein Expression as a Potential Novel Biomarker for DNA Damage Response-Targeted Therapies in Breast Cancer

Disruption of Cyclin-Dependent Kinase 12 (CDK12) is known to lead to defects in DNA repair and sensitivity to platinum salts and PARP1/2 inhibitors. However, CDK12 has also been proposed as an oncogene in breast cancer. We therefore aimed to assess the frequency and distribution of CDK12 protein expression by IHC in independent cohorts of breast cancer and correlate this with outcome and genomic status. We found that 21% of primary unselected breast cancers were CDK12 high, and 10.5% were absent, by IHC. CDK12 positivity correlated with HER2 positivity but was not an independent predictor of breast cancer-specific survival taking HER2 status into account; however, absent CDK12 protein expression significantly correlated with a triple-negative phenotype. Interestingly, CDK12 protein absence was associated with reduced expression of a number of DDR proteins including ATR, Ku70/Ku80, PARP1, DNA-PK, and γH2AX, suggesting a novel mechanism of CDK12-associated DDR dysregulation in breast cancer. Our data suggest that diagnostic IHC quantification of CDK12 in breast cancer is feasible, with CDK12 absence possibly signifying defective DDR function. This may have important therapeutic implications, particularly for triple-negative breast cancers. Mol Cancer Ther; 17(1); 306-15. ©2017 AACR.

The localization of pre mRNA splicing factor PRPF38B is a novel prognostic biomarker that may predict survival benefit of trastuzumab in patients with breast cancer overexpressing HER2

Cancer biomarkers that can define disease status and provide a prognostic insight are essential for the effective management of patients with breast cancer (BC).

The prevalence, clinicopathological and prognostic significance of PRPF38B expression in a consecutive series of 1650 patients with primary invasive breast carcinoma were examined using immunohistochemistry. Furthermore, the relationship(s) between clinical outcome and PRPF38B expression was explored in 627 patients with ER-negative (oestrogen receptor) disease, and 322 patients with HER2-overexpressing disease.

Membranous expression of PRPF38B was observed in 148/1388 (10.7%) cases and was significantly associated with aggressive clinicopathological features, including high grade, high mitotic index, pleomorphism, invasive ductal carcinoma of no specific type (IDC-NST), ER-negative, HER2-overexpression and p53 mutational status (all p < 0.01). In patients with ER-negative disease receiving chemotherapy, nuclear expression of PRPF38B was significantly associated with a reduced risk of relapse (p = 0.0004), whereas membranous PRPF38B expression was significantly associated with increased risk of relapse (p = 0.004; respectively) at a 5 year follow-up. When patients were stratified according to ER-negative/HER2-positive status, membranous PRPF38B expression was associated with a higher risk of relapse in those patients that did not receive trastuzumab therapy (p = 0.02), whereas in those patients with ER-negative/HER2-positive disease that received trastuzumab adjuvant therapy, membranous PRPF38B expression associated with a lower risk of relapse (p = 0.00018).

Nuclear expression of PRPF38B is a good prognostic indicator in both ER-negative patients and ER-negative/HER2-positive BC (breast cancer) patients, whereas membranous localisation of PRPF38B is a poor prognostic biomarker that predicts survival benefit from trastuzumab therapy in patients with ER-negative/HER2-overexpressing BC.

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&gt;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.

DNA repair prognostic index modelling reveals an essential role for base excision repair in influencing clinical outcomes in ER negative and triple negative breast cancers

Stratification of oestrogen receptor (ER) negative and triple negative breast cancers (TNBCs) is urgently needed. In the current study, a cohort of 880 ER- (including 635 TNBCs) was immuno-profiled for a panel of DNA repair proteins including: Pol β, FEN1, APE1, XRCC1, SMUG1, PARP1, BRCA1, ATR, ATM, DNA-PKcs, Chk1, Chk2, p53, and TOPO2. Multivariate Cox proportional hazards models (with backward stepwise exclusion of these factors, using a criterion of p < 0.05 for retention of factors in the model) were used to identify factors that were independently associated with clinical outcomes. XRCC1 (p = 0.002), pol β (p = 0.032) FEN1 (p = 0.001) and BRCA1 (p = 0.040) levels were independently associated with poor BCSS. Subsequently, DNA repair index prognostic (DRPI) scores for breast cancer specific survival (BCSS) were calculated and two prognostic groups (DRPI-PGs) were identified. Patients in prognostic group 2 (DRPI-PG2) have higher risk of death (p < 0.001). Furthermore, in DRPI-PG2 patients, exposure to anthracycline reduced the risk of death [(HR (95% CI) = 0.79 (0.64–0.98), p = 0.032) by 21–26%. In addition, DRPI-PG2 patients have adverse clinicopathological features including higher grade, lympho-vascular invasion, Her-2 positive phenotype, compared to those in DRPI-PG1 (p < 0.01). Receiver operating characteristic (ROC) curves indicated that the DRPI outperformed the currently used prognostic factors and adding DRPI to lymph node stage significantly improved their performance as a predictor for BCSS [p < 0.00001, area under curve (AUC) = 0.70]. BER strongly influences pathogenesis of ER- and TNBCs. The DRPI accurately predicts BCSS and can also serve as a valuable prognostic and predictive tool for TNBCs.

SPAG5 as a prognostic biomarker and chemotherapy sensitivity predictor in breast cancer: a retrospective, integrated genomic, transcriptomic, and protein analysis

BACKGROUND

Proliferation markers and profiles have been recommended for guiding the choice of systemic treatments for breast cancer. However, the best molecular marker or test to use has not yet been identified. We did this study to identify factors that drive proliferation and its associated features in breast cancer and assess their association with clinical outcomes and response to chemotherapy.

METHODS

We applied an artificial neural network-based integrative data mining approach to data from three cohorts of patients with breast cancer (the Nottingham discovery cohort (n=171), Uppsala cohort (n=249), and Molecular Taxonomy of Breast Cancer International Consortium [METABRIC] cohort; n=1980). We then identified the genes with the most effect on other genes in the resulting interactome map. Sperm-associated antigen 5 (SPAG5) featured prominently in our interactome map of proliferation and we chose to take it forward in our analysis on the basis of its fundamental role in the function and dynamic regulation of mitotic spindles, mitotic progression, and chromosome segregation fidelity. We investigated the clinicopathological relevance of SPAG5 gene copy number aberrations, mRNA transcript expression, and protein expression and analysed the associations of SPAG5 copy number aberrations, transcript expression, and protein expression with breast cancer-specific survival, disease-free survival, distant relapse-free survival, pathological complete response, and residual cancer burden in the Nottingham discovery cohort, Uppsala cohort, METABRIC cohort, a pooled untreated lymph node-negative cohort (n=684), a multicentre combined cohort (n=5439), the Nottingham historical early stage breast cancer cohort (Nottingham-HES; n=1650), Nottingham early stage oestrogen receptor-negative breast cancer adjuvant chemotherapy cohort (Nottingham-oestrogen receptor-negative-ACT; n=697), the Nottingham anthracycline neoadjuvant chemotherapy cohort (Nottingham-NeoACT; n=200), the MD Anderson taxane plus anthracycline-based neoadjuvant chemotherapy cohort (MD Anderson-NeoACT; n=508), and the multicentre phase 2 neoadjuvant clinical trial cohort (phase 2 NeoACT; NCT00455533; n=253).

FINDINGS

In the METABRIC cohort, we detected SPAG5 gene gain or amplification at the Ch17q11.2 locus in 206 (10%) of 1980 patients overall, 46 (19%) of 237 patients with a PAM50-HER2 phenotype, and 87 (18%) of 488 patients with PAM50-LumB phenotype. Copy number aberration leading to SPAG5 gain or amplification and high SPAG5 transcript and SPAG5 protein concentrations were associated with shorter overall breast cancer-specific survival (METABRIC cohort [copy number aberration]: hazard ratio [HR] 1·50, 95% CI 1·18-1·92, p=0·00010; METABRIC cohort [transcript]: 1·68, 1·40-2·01, p<0·0001; and Nottingham-HES-breast cancer cohort [protein]: 1·68, 1·32-2·12, p<0·0001). In multivariable analysis, high SPAG5 transcript and SPAG5 protein expression were associated with reduced breast cancer-specific survival at 10 years compared with lower concentrations (Uppsala: HR 1·62, 95% CI 1·03-2·53, p=0·036; METABRIC: 1·27, 1·02-1·58, p=0·034; untreated lymph node-negative cohort: 2·34, 1·24-4·42, p=0·0090; and Nottingham-HES: 1·73, 1·23-2·46, p=0·0020). In patients with oestrogen receptor-negative breast cancer with high SPAG5 protein expression, anthracycline-based adjuvant chemotherapy increased breast cancer-specific survival overall compared with that for patients who did not receive chemotherapy (Nottingham-oestrogen receptor-negative-ACT cohort: HR 0·37, 95% CI 0·20-0·60, p=0·0010). Multivariable analysis showed high SPAG5 transcript concentrations to be independently associated with longer distant relapse-free survival after receiving taxane plus anthracycline neoadjuvant chemotherapy (MD Anderson-NeoACT: HR 0·68, 95% CI 0·48-0·97, p=0·031). In multivariable analysis, both high SPAG5 transcript and high SPAG5 protein concentrations were independent predictors for a higher proportion of patients achieving a pathological complete response after combination cytotoxic chemotherapy (MD Anderson-NeoACT: OR 1·71, 95% CI, 1·07-2·74, p=0·024; Nottingham-ACT: 8·75, 2·42-31·62, p=0·0010).

INTERPRETATION

SPAG5 is a novel amplified gene on Ch17q11.2 in breast cancer. 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, especially in oestrogen receptor-negative breast cancer.

FUNDING

Nottingham Hospitals Charity and the John and Lucille van Geest Foundation.

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&lt;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&lt;0.001.

There was a significant positive correlations between p-Jnk and p-c-Jun protein levels (p&lt;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&lt;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&lt;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&lt;0.05.

JNK+ (mRNA and p-Jnk) and c-JUN+ (mRNA and p-c-Jun) individually were associated with prolonged BC specific survival (ps&lt;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.

SRC3 Phosphorylation at Serine 543 Is a Positive Independent Prognostic Factor in ER-Positive Breast Cancer

PURPOSE

The steroid receptor coactivator SRC3 is essential for the transcriptional activity of estrogen receptor α (ERα). SRC3 is sufficient to cause mammary tumorigenesis, and has also been implicated in endocrine resistance. SRC3 is posttranslationally modified by phosphorylation, but these events have not been investigated with regard to functionality or disease association. Here, we investigate the spatial selectivity of SRC3-pS543/DNA binding over the human genome and its expression in primary human breast cancer in relation with outcome.

EXPERIMENTAL DESIGN

Chromatin immunoprecipitation, coupled with sequencing, was used to determine the chromatin binding patterns of SRC3-pS543 in the breast cancer cell line MCF7 and two untreated primary breast cancers. IHC was used to assess the expression of SRC3 and SRC3-pS543 in 1,650 primary breast cancers. The relationship between the expression of SRC3 and SRC3-pS543, disease-free survival (DFS), and breast cancer specific survival (BCSS) was assessed.

RESULTS

Although total SRC3 is selectively found at enhancer regions, SRC3-pS543 is recruited to promoters of ERα responsive genes, both in the MCF7 cell line and primary breast tumor specimens. SRC3-pS543 was associated with both improved DFS (P = 0.003) and BCSS (P = 0.001) in tamoxifen untreated high-risk patients, such a correlation was not seen in tamoxifen-treated cases, the interaction was statistically significant (P = 0.001). Multivariate analysis showed SRC3-pS543 to be an independent prognostic factor.

CONCLUSIONS

Phosphorylation of SRC3 at S543 affects its genomic interactions on a genome-wide level, where SRC3-pS543 is selectively recruited to promoters of ERα-responsive genes. SRC3-pS543 is a prognostic marker, and a predictive marker of response to endocrine therapy.

Clinicopathological and prognostic significance of RECQL5 helicase expression in breast cancers

RECQL5 is a member of the RecQ family of DNA helicases and has key roles in homologous recombination, base excision repair, replication and transcription. The clinicopathological significance of RECQL5 expression in breast cancer is unknown. In this study, we have evaluated RECQL5 mRNA expression in 1977 breast cancers, and RECQL5 protein level in 1902 breast cancers [Nottingham Tenovus series (n = 1650) and ER- cohort (n = 252)]. Expression levels were correlated to aggressive phenotypes and survival outcomes. High RECQL5 mRNA expression was significantly associated with high histological grade (P = 0.007), HER2 overexpression (P = 0.032), ER+/HER2-/high proliferation genefu subtype (P < 0.0001), integrative molecular clusters (intClust 1and 9) (P < 0.0001) and poor survival (P < 0.0001). In subgroup analysis, high RECQL5 mRNA level remains significantly associated with poor BCSS in ER+ cohort (P < 0.0001) but not in ER- cohort (P = 0.116). At the protein level, in tumours with low RAD51, high RECQL5 level was significantly associated with high histological grade (P < 0.0001), higher mitotic index (P = 0.008), dedifferentiation (P = 0.025), pleomorphism (P = 0.027) and poor survival (P = 0.003). In subgroup analysis, high RECQL5/low RAD51 remains significantly associated with poor BCSS in ER+ cohort (P = 0.010), but not in ER- cohort (P = 0.628). In multivariate analysis, high RECQL5 mRNA and high RECQL5/low RAD51 nuclear protein coexpression independently influenced survival (P = 0.022) in whole cohort and in the ER+ subgroup. Preclinically, we show that exogenous expression of RECQL5 in MCF10A cells can drive proliferation supporting an oncogenic function for RECQL5 in breast cancer. We conclude that RECQL5 is a promising biomarker in breast cancer.

Chk1 phosphorylated at serine345 is a predictor of early local recurrence and radio-resistance in breast cancer

Radiation-induced DNA damage activates the DNA damage response (DDR). DDR up-regulation may predict radio-resistance and increase the risk of early local recurrence despite radiotherapy in early stage breast cancers. In 1755 early stage breast cancers, DDR signalling [ATM, ATR, total Ckh1, Chk1 phosphorylated at serine(345) (pChk1), Chk2, p53], base excision repair [PARP1, POLβ, XRCC1, FEN1, SMUG1], non-homologous end joining (Ku70/Ku80, DNA-PKcs) and homologous recombination [RAD51, BRCA1, γH2AX, BLM, WRN, RECQL5, PTEN] protein expression was correlated to time to early local recurrence. Pre-clinically, radio-sensitization by inhibition of Chk1 activation by ATR inhibitor (VE-821) and inhibition of Chk1 (V158411) were investigated in MDA-MB-231 (p53 mutant) and MCF-7 (p53 wild-type) breast cancer cells. In the whole cohort, 208/1755 patients (11.9%) developed local recurrence of which 126 (61%) developed local recurrence within 5 years of initiation of primary therapy. Of the 20 markers tested, only pChk1 and p53 significantly associated with early local recurrence (p value = 0.015 and 0.010, respectively). When analysed together, high cytoplasmic pChk1-nuclear pChk1 (p = 0.039), high cytoplasmic pChk1-p53 (p = 0.004) and high nuclear pChk1-p53 (p = 0.029) co-expression remain significantly linked to early local recurrence. In multivariate analysis, cytoplasmic pChk1 level independently predicted early local recurrence (p = 0.025). In patients who received adjuvant local radiotherapy (n = 949), p53 (p = 0.014) and high cytoplasmic pChk1-p53 (p = 0.017) remain associated with early local recurrence. Pre-clinically, radio-sensitisation by VE-821 or V158411 was observed in both MCF-7 and MDA-MB-231 cells and was more pronounced in MCF-7 cells. We conclude that pChk1 is a predictive biomarker of radiotherapy resistance and early local recurrence.

HAGE in Triple-Negative Breast Cancer Is a Novel Prognostic, Predictive, and Actionable Biomarker: A Transcriptomic and Protein Expression Analysis

PURPOSE

The expression of HAGE as a novel prognostic and predictive tool was assessed in 1,079 triple-negative breast cancers (TNBC).

EXPERIMENTAL DESIGN

HAGE protein expression was investigated in an early primary TNBC (EP-TNBC; n = 520) cohort who received adjuvant chemotherapy (ACT) and in a locally advanced primary TNBC cohort who received anthracycline combination Neo-ACT (n = 110; AC-Neo-ACT). HAGE-mRNA expression was evaluated in the METABRIC-TNBC cohort (n = 311) who received ACT and in a cohort of patients with TNBC who received doxorubicin/cyclophosphamide Neo-ACT, followed by 1:1 randomization to ixabepilone (n = 68) or paclitaxel (n = 64) as part of a phase II clinical trial. Furthermore, a cohort of 128 tumors with integrated HAGE gene copy number changes, mRNA, and protein levels were analyzed.

RESULTS

In patients with EP-TNBC, who were chemotherapy-naïve, high HAGE protein expression (HAGE(+)) was associated with a higher risk of death [HR, 1.3; 95% confidence interval (CI), 1.2-1.5; P = 0.000005] when compared with HAGE(-) cases. Patients who received ACT and expressed mRNA-HAGE(+) were at a lower risk of death than those who were mRNA-HAGE(-) (P = 0.004). The expression of HAGE was linked to the presence of tumor-infiltrating lymphocytes (TIL), and both features were found to be independent predictors for pathologic complete response (pCR, P < 0.001) and associated with prolonged survival (P < 0.01), following AC-Neo-ACT. In patients with residual disease, HAGE(+) had a 2-fold death risk increase (P = 0.018) compared with HAGE(-).

CONCLUSIONS

HAGE expression is a potential prognostic marker and a predictor of response to anthracycline treatment in TNBC. A prospective clinical trial to examine the therapeutic value of HAGE for TNBC cases is warranted.

Dissecting DNA repair in adult high grade gliomas for patient stratification in the post-genomic era

Deregulation of multiple DNA repair pathways may contribute to aggressive biology and therapy resistance in gliomas. We evaluated transcript levels of 157 genes involved in DNA repair in an adult glioblastoma Test set (n=191) and validated in ‘The Cancer Genome Atlas’ (TCGA) cohort (n=508). A DNA repair prognostic index model was generated. Artificial neural network analysis (ANN) was conducted to investigate global gene interactions. Protein expression by immunohistochemistry was conducted in 61 tumours. A fourteen DNA repair gene expression panel was associated with poor survival in Test and TCGA cohorts. A Cox multivariate model revealed APE1, NBN, PMS2, MGMT and PTEN as independently associated with poor prognosis. A DNA repair prognostic index incorporating APE1, NBN, PMS2, MGMT and PTEN stratified patients in to three prognostic sub-groups with worsening survival. APE1, NBN, PMS2, MGMT and PTEN also have predictive significance in patients who received chemotherapy and/or radiotherapy. ANN analysis of APE1, NBN, PMS2, MGMT and PTEN revealed interactions with genes involved in transcription, hypoxia and metabolic regulation. At the protein level, low APE1 and low PTEN remain associated with poor prognosis. In conclusion, multiple DNA repair pathways operate to influence biology and clinical outcomes in adult high grade gliomas.

Transcriptomic and Protein Expression Analysis Reveals Clinicopathological Significance of Bloom Syndrome Helicase (BLM) in Breast Cancer

Bloom syndrome helicase (BLM) has key roles in homologous recombination repair, telomere maintenance, and DNA replication. Germ-line mutations in the BLM gene causes Bloom syndrome, a rare disorder characterized by premature aging and predisposition to multiple cancers, including breast cancer. The clinicopathologic significance of BLM in sporadic breast cancers is unknown. We investigated BLM mRNA expression in the Molecular Taxonomy of Breast Cancer International Consortium cohort (n = 1,950) and validated in an external dataset of 2,413 tumors. BLM protein level was evaluated in the Nottingham Tenovus series comprising 1,650 breast tumors. BLM mRNA overexpression was significantly associated with high histologic grade, larger tumor size, estrogen receptor-negative (ER(-)), progesterone receptor-negative (PR(-)), and triple-negative phenotypes (ps < 0.0001). BLM mRNA overexpression was also linked to aggressive molecular phenotypes, including PAM50.Her2 (P < 0.0001), PAM50.Basal (P < 0.0001), and PAM50.LumB (P < 0.0001) and Genufu subtype (ER(+)/Her2(-)/high proliferation; P < 0.0001). PAM50.LumA tumors and Genufu subtype (ER(+)/Her2(-)/low proliferation) were more likely to express low levels of BLM mRNA (ps < 0.0001). Integrative molecular clusters (intClust) intClust.1 (P < 0.0001), intClust.5 (P < 0.0001), intClust.9 (P < 0.0001), and intClust.10 (P < 0.0001) were also more likely in tumors with high BLM mRNA expression. BLM mRNA overexpression was associated with poor breast cancer-specific survival (BCSS; ps < 0.000001). At the protein level, altered subcellular localization with high cytoplasmic BLM and low nuclear BLM was linked to aggressive phenotypes. In multivariate analysis, BLM mRNA and BLM protein levels independently influenced BCSS. This is the first and the largest study to provide evidence that BLM is a promising biomarker in breast cancer.

Targeting BRCA1-BER deficient breast cancer by ATM or DNA-PKcs blockade either alone or in combination with cisplatin for personalized therapy

BRCA1, a key factor in homologous recombination (HR) repair may also regulate base excision repair (BER). Targeting BRCA1-BER deficient cells by blockade of ATM and DNA-PKcs could be a promising strategy in breast cancer. We investigated BRCA1, XRCC1 and pol β protein expression in two cohorts (n = 1602 sporadic and n = 50 germ-line BRCA1 mutated) and mRNA expression in two cohorts (n = 1952 and n = 249). Artificial neural network analysis for BRCA1-DNA repair interacting genes was conducted in 249 tumours. Pre-clinically, BRCA1 proficient and deficient cells were DNA repair expression profiled and evaluated for synthetic lethality using ATM and DNA-PKcs inhibitors either alone or in combination with cisplatin. In human tumours, BRCA1 negativity was strongly associated with low XRCC1, and low pol β at mRNA and protein levels (p < 0.0001). In patients with BRCA1 negative tumours, low XRCC1 or low pol β expression was significantly associated with poor survival in univariate and multivariate analysis compared to high XRCC1 or high pol β expressing BRCA1 negative tumours (ps < 0.05). Pre-clinically, BRCA1 negative cancer cells exhibit low mRNA and low protein expression of XRCC1 and pol β. BRCA1-BER deficient cells were sensitive to ATM and DNA-PKcs inhibitor treatment either alone or in combination with cisplatin and synthetic lethality was evidenced by DNA double strand breaks accumulation, cell cycle arrest and apoptosis. We conclude that XRCC1 and pol β expression status in BRCA1 negative tumours may have prognostic significance. BRCA1-BER deficient cells could be targeted by ATM or DNA-PKcs inhibitors for personalized therapy.

Is there a role for base excision repair in estrogen/estrogen receptor-driven breast cancers?

Estrogen and estrogen metabolite-induced reactive oxygen species generation can promote oxidative DNA base damage. If unrepaired, base damaging lesions could accelerate mutagenesis, leading to a "mutator phenotype" characterized by aggressive behavior in estrogen-estrogen receptor (ER)-driven breast cancer. To test this hypothesis, we investigated 1406 ER(+) early-stage breast cancers with 20 years' long-term clinical follow-up data for DNA polymerase β (pol β), flap endonuclease 1 (FEN1), AP endonuclease 1 (APE1), X-ray cross-complementation group 1 protein (XRCC1), single-strand monofunctional uracil glycosylase-1 (SMUG1), poly (ADP-ribose) polymerase 1 (PARP1), ataxia telangiectasia mutated and Rad3 related (ATR), ataxia telangiectasia mutated (ATM), DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Chk1, Chk2, p53, breast cancer susceptibility gene 1 (BRCA1), and topoisomerase 2 (TOPO2) expression. Multivariate Cox proportional hazards model was used to calculate a DNA repair prognostic index and correlated to clinicopathological variables and survival outcomes. Key base excision repair (BER) proteins, including XRCC1, APE1, SMUG1, and FEN1, were independently associated with poor breast cancer-specific survival (BCSS) (ps≤0.01). Multivariate Cox model stratified patients into four distinct prognostic sub-groups with worsening BCSS (ps<0.01). In addition, compared with prognostic sub-group 1, sub-groups 2, 3, and 4 manifest increasing tumor size, grade, mitosis, pleomorphism, differentiation, lymphovascular invasion, high Ki67, loss of Bcl-2, luminal B phenotype (ps≤0.01), and poor survival, including in patients who received tamoxifen adjuvant therapy (p<0.00001). Our observation supports the hypothesis that BER-directed stratification could inform appropriate therapies in estrogen-ER-driven breast cancers. Antioxid.

Untangling the ATR-CHEK1 network for prognostication, prediction and therapeutic target validation in breast cancer

ATR-CHEK1 signalling is critical for genomic stability. ATR-CHEK1 signalling may be deregulated in breast cancer and have prognostic, predictive and therapeutic significance. We investigated ATR, CHEK1 and phosphorylated CHEK1 (Ser345) protein (pCHEK1) levels in 1712 breast cancers. ATR and CHEK1 mRNA expression was evaluated in 1950 breast cancers. Pre-clinically, biological consequences of ATR gene knock down or ATR inhibition by the small molecule inhibitor (VE-821) were investigated in MCF7 and MDA-MB-231 breast cancer cell lines and in non-tumorigenic breast epithelial cells (MCF10A). High ATR and high cytoplasmic pCHEK1 levels were significantly associated with higher tumour stage, higher mitotic index, pleomorphism and lymphovascular invasion. In univariate analyses, high ATR and high cytoplasmic pCHEK1 levels were associated with poor breast cancer specific survival (BCSS). In multivariate analysis, high ATR level remains an independent predictor of adverse outcome. At the mRNA level, high CHEK1 remains associated with aggressive phenotypes including lymph node positivity, high grade, Her-2 overexpression, triple negative, aggressive molecular phenotypes and adverse BCSS. Pre-clinically, CHEK1 phosphorylation at serine(345) following replication stress was impaired in ATR knock down and in VE-821 treated breast cancer cells. Doxycycline inducible knockdown of ATR suppressed growth, which was restored when ATR was re-expressed. Similarly, VE-821 treatment resulted in a dose dependent suppression of cancer cell growth and survival (MCF7 and MDA-MB-231) but was less toxic in non-tumorigenic breast epithelial cells (MCF10A). We provide evidence that ATR and CHEK1 are promising biomarkers and rational drug targets for personalized therapy in breast cancer.

Genomic and protein expression analysis reveals flap endonuclease 1 (FEN1) as a key biomarker in breast and ovarian cancer

FEN1 has key roles in Okazaki fragment maturation during replication, long patch base excision repair, rescue of stalled replication forks, maintenance of telomere stability and apoptosis. FEN1 may be dysregulated in breast and ovarian cancers and have clinicopathological significance in patients. We comprehensively investigated FEN1 mRNA expression in multiple cohorts of breast cancer [training set (128), test set (249), external validation (1952)]. FEN1 protein expression was evaluated in 568 oestrogen receptor (ER) negative breast cancers, 894 ER positive breast cancers and 156 ovarian epithelial cancers. FEN1 mRNA overexpression was highly significantly associated with high grade (p = 4.89 × 10(-57)), high mitotic index (p = 5.25 × 10(-28)), pleomorphism (p = 6.31 × 10(-19)), ER negative (p = 9.02 × 10(-35)), PR negative (p = 9.24 × 10(-24)), triple negative phenotype (p = 6.67 × 10(-21)), PAM50.Her2 (p = 5.19 × 10(-13)), PAM50. Basal (p = 2.7 × 10(-41)), PAM50.LumB (p = 1.56 × 10(-26)), integrative molecular cluster 1 (intClust.1) (p = 7.47 × 10(-12)), intClust.5 (p = 4.05 × 10(-12)) and intClust. 10 (p = 7.59 × 10(-38)) breast cancers. FEN1 mRNA overexpression is associated with poor breast cancer specific survival in univariate (p = 4.4 × 10(-16)) and multivariate analysis (p = 9.19 × 10(-7)). At the protein level, in ER positive tumours, FEN1 overexpression remains significantly linked to high grade, high mitotic index and pleomorphism (ps < 0.01). In ER negative tumours, high FEN1 is significantly associated with pleomorphism, tumour type, lymphovascular invasion, triple negative phenotype, EGFR and HER2 expression (ps < 0.05). In ER positive as well as in ER negative tumours, FEN1 protein overexpression is associated with poor survival in univariate and multivariate analysis (ps < 0.01). In ovarian epithelial cancers, similarly, FEN1 overexpression is associated with high grade, high stage and poor survival (ps < 0.05). We conclude that FEN1 is a promising biomarker in breast and ovarian epithelial cancer.

Phosphorylation of activating transcription factor-2 (ATF-2) within the activation domain is a key determinant of sensitivity to tamoxifen in breast cancer

Activating transcription factor-2 (ATF-2) has been implicated as a tumour suppressor in breast cancer (BC). c-JUN N-terminal kinase (JNK) and p38 MAPK phosphorylate ATF-2 within the activation domain (AD), which is required for its transcriptional activity. To date, the role of ATF-2 in determining response to endocrine therapy has not been explored. Effects of ATF-2 loss in the oestrogen receptor (ER)-positive luminal BC cell line MCF7 were explored, as well as its role in response to tamoxifen treatment. Genome-wide chromatin binding patterns of ATF-2 when phosphorylated within the AD in MCF-7 cells were determined using ChIP-seq. The expression of ATF-2 and phosphorylated ATF-2 (pATF-2-Thr71) was determined in a series of 1,650 BC patients and correlated with clinico-pathological features and clinical outcome. Loss of ATF-2 diminished the growth-inhibitory effects of tamoxifen, while tamoxifen treatment induced ATF-2 phosphorylation within the AD, to regulate the expression of a set of 227 genes for proximal phospho-ATF-2 binding, involved in cell development, assembly and survival. Low expression of both ATF-2 and pATF-2-Thr71 was significantly associated with aggressive pathological features. Furthermore, pATF-2 was associated with both p-p38 and pJNK1/2 (< 0.0001). While expression of ATF-2 is not associated with outcome, pATF-2 is associated with longer disease-free (p = 0.002) and BC-specific survival in patients exposed to tamoxifen (p = 0.01). Furthermore, multivariate analysis confirmed pATF-2-Thr71 as an independent prognostic factor. ATF-2 is important for modulating the effect of tamoxifen and phosphorylation of ATF-2 within the AD at Thr71 predicts for improved outcome for ER-positive BC receiving tamoxifen.

DNA polymerase β deficiency is linked to aggressive breast cancer: a comprehensive analysis of gene copy number, mRNA and protein expression in multiple cohorts

Short arm of chromosome 8 is a hot spot for chromosomal breaks, losses and amplifications in breast cancer. Although such genetic changes may have phenotypic consequences, the identity of candidate gene(s) remains to be clearly defined. Pol β gene is localized to chromosome 8p12-p11 and encodes a key DNA base excision repair protein. Pol β may be a tumour suppressor and involved in breast cancer pathogenesis. We conducted the first and the largest study to comprehensively evaluate pol β in breast cancer. We investigated pol β gene copy number changes in two cohorts (n = 128 &n = 1952), pol β mRNA expression in two cohorts (n = 249 &n = 1952) and pol β protein expression in two cohorts (n = 1406 &n = 252). Artificial neural network analysis for pol β interacting genes was performed in 249 tumours. For mechanistic insights, pol β gene copy number changes, mRNA and protein levels were investigated together in 128 tumours and validated in 1952 tumours. Low pol β mRNA expression as well as low pol β protein expression was associated high grade, lymph node positivity, pleomorphism, triple negative, basal-like phenotypes and poor survival (ps < 0.001). In oestrogen receptor (ER) positive sub-group that received tamoxifen, low pol β protein remains associated with aggressive phenotype and poor survival (ps < 0.001). Artificial neural network analysis revealed ER as a top pol β interacting gene. Mechanistically, there was strong positive correlation between pol β gene copy number changes and pol β mRNA expression (p < 0.0000001) and between pol β mRNA and pol β protein expression (p < 0.0000001). This is the first study to provide evidence that pol β deficiency is linked to aggressive breast cancer and may have prognostic and predictive significance in patients.

HER2/HER3 heterodimers and p21 expression are capable of predicting adjuvant trastuzumab response in HER2+ breast cancer

Human epidermal growth factor receptor 2 (HER2) plays an important role in breast cancer progression and provides predictive information for response to targeted therapy including trastuzumab although this is limited. Downstream pathways, such as PI3K/Akt, are associated with HER2/HER3 heterodimerization promoting survival and proliferation amongst cancer cells. Thus, patient outcome and trastuzumab therapy effectiveness might be further characterised by HER2/HER3 dimerisation and its signalling pathways. HER2/HER3 dimerisation status was assessed, using chromogenic in situ Proximity Ligation Assay, in two breast cancer series: early stage primary breast cancer, including 224 HER2+ patients that were not submitted to trastuzumab, and HER2+ breast cancer where patients were treated with adjuvant trastuzumab (n = 143). Levels of biomarkers including PI3K, pAKT, ER, PgR, HER3, BCL2, p53, PTEN and p21 were measured using immunohistochemistry. Levels of HER2/HER3 heterodimers were compared with biomarker expression and patient outcome. An association between high levels of HER2/HER3 dimerisation and absence of hormone receptors, ER and PgR, was observed. We further show for the first time the presence of HER2/HER3 heterodimers and the loss of p21 expression in HER2+ breast cancer predicts a significantly poorer outcome when submitted to adjuvant trastuzumab. Breast cancer patients that reveal high levels of HER2/HER3 dimerisation and loss of p21 are associated with poor survival prognosis in patients with HER2+ breast cancer treated with adjuvant trastuzumab. Further quantification analysis of HER dimer/ligand complexes and downstream signalling pathways will begin to unravel the complex associations with patient outcome and its relationship with sensitivity to targeted treatment.

Characterisation of HER heterodimers in breast cancer using in situ proximity ligation assay

HER2 plays an important role in breast cancer progression and provides predictive and prognostic information. HER2 receptor family members function through dimerisation, which can lead to impact on cell function, growth and differentiation; however, their value in breast cancer development remains to be defined. This study aims to examine the relationships of HER2 heterodimers to breast cancer characteristics in trastuzumab naïve and treated cases. HER2 protein (IHC), HER2 gene (chromogenic ISH) and HER2 heterodimerisation status [chromogenic in situ proximity ligation assay (PLA)] were assessed in two breast cancer series prepared in tissue microarray (TMA) format. A range of signals/cell for each HER2 heterodimer was detected (0-34.6 signals/cell). The vast majority of cases with HER2 heterodimers showed HER2 gene amplification and/or protein expression. There was an association between HER2 dimerisation with HER3 and HER4 and their protein expression level but no such association was found in with HER1 (EGFR). Of the HER2+ cases, 74, 66, and 58 % showed heterodimers with EGFR, HER3 and HER4, respectively. 51 % of HER2+ tumours expressed all three heterodimers whereas 23 % of the cases did not show expression of any of the three heterodimers. There was an inverse association between the presence and levels of HER2 heterodimers and hormone receptor expression in HER2+ tumours. Tumours exhibiting high levels of HER2 heterodimers demonstrated aggressive clinicopathological features and poor outcome. In the HER2+ cases, dimerisation with EGFR and HER3 but not with HER4 showed an association with aggressive features. There was no association between HER2 heterodimers with patient breast cancer-specific survival or recurrence in HER2+ breast cancer in those patients receiving trastuzumab or not. Our results demonstrate that HER2 dimerisation is a complex process that may underlie the biological heterogeneity of HER2 positive tumours and may identify patients suitable for a specific targeted therapy but does not predict patient outcome for those receiving trastuzumab. PLA proved to be a useful tool for detecting, visualising and quantifying the frequency of protein-protein interactions in archival formalin-fixed paraffin-embedded tissue samples.

Clinicopathological significance of human apurinic/apyrimidinic endonuclease 1 (APE1) expression in oestrogen-receptor-positive breast cancer

Oestrogen metabolites can induce oxidative DNA base damage and generate potentially mutagenic apurinic sites (AP sites) in the genomic DNA. If unrepaired, mutagenic AP sites could drive breast cancer pathogenesis and aggressive phenotypes. Human apurinic/apyrimidinic endonuclease 1 (APE1) is a key DNA base excision repair (BER) protein and essential for processing AP sites generated either directly by oestrogen metabolites or during BER of oxidative base damage. Our hypothesis is that altered APE1 expression may be associated with aggressive tumour biology and impact upon clinical outcomes in breast cancer. In the current study, we have investigated APE1 protein expression in a large cohort of breast cancers (n = 1285) and correlated to clinicopathological features and survival outcomes. Low APE1 protein expression was associated with high histological grade (p < 0.000001), high mitotic index (p < 0.000001), glandular de-differentiation (p < 0.000001), pleomorphism (p = 0.003), absence of hormonal receptors (ER-/PgR-/AR-) (p < 0.0001) and presence of triple negative phenotype (p = 0.001). Low APE1 protein expression was associated with loss of BRCA1, low XRCC1, low FEN1, low SMUG1 and low pol β (ps < 0.0001). High MIB1 (p = 0.048), bcl-2 negativity (p < 0.0001) and low TOP2A (p < 0.0001) were likely in low APE1 tumours. In the ER-positive sub-group, specifically, low APE1 remains significantly associated with high histological grade, high mitotic index, glandular de-differentiation (ps < 0.00001) and poor breast cancer specific survival (p = 0.007). In the ER-positive cohort that received adjuvant endocrine therapy, low APE1 protein expression is associated with poor survival (p = 0.006). In multivariate analysis, low APE1 remains independently associated with poor survival in ER-positive tumours (p = 0.048). We conclude that low APE1 expression may have prognostic and predictive significance in ER-positive breast cancers.

Single-strand selective monofunctional uracil-DNA glycosylase (SMUG1) deficiency is linked to aggressive breast cancer and predicts response to adjuvant therapy

Uracil in DNA is an important cause of mutagenesis. SMUG1 is a uracil-DNA glycosylase that removes uracil through base excision repair. SMUG1 also processes radiation-induced oxidative base damage as well as 5-fluorouracil incorporated into DNA during chemotherapy. We investigated SMUG1 mRNA expression in 249 primary breast cancers. SMUG1 protein expression was investigated in 1,165 breast tumours randomised into two cohorts [training set (n = 583) and test set (n = 582)]. SMUG1 and chemotherapy response was also investigated in a series of 315 ER-negative tumours (n = 315). For mechanistic insights, SMUG1 was correlated to biomarkers of aggressive phenotype, DNA repair, cell cycle and apoptosis. Low SMUG1 mRNA expression was associated with adverse disease specific survival (p = 0.008) and disease-free survival (p = 0.008). Low SMUG1 protein expression (25 %) was associated with high histological grade (p < 0.0001), high mitotic index (p < 0.0001), pleomorphism (p < 0.0001), glandular de-differentiation (p = 0.0001), absence of hormonal receptors (ER-/PgR-/AR) (p < 0.0001), presence of basal-like (p < 0.0001) and triple-negative phenotypes (p < 0.0001). Low SMUG1 protein expression was associated with loss of BRCA1 (p < 0.0001), ATM (p < 0.0001) and XRCC1 (p < 0.0001). Low p27 (p < 0.0001), low p21 (p = 0.023), mutant p53 (p = 0.037), low MDM2 (p < 0.0001), low MDM4 (p = 0.004), low Bcl-2 (p = 0.001), low Bax (p = 0.003) and high MIB1 (p < 0.0001) were likely in low SMUG1 tumours. Low SMUG1 protein expression was associated with poor prognosis in univariate (p < 0.001) and multivariate analysis (p < 0.01). In ER+ cohort that received adjuvant endocrine therapy, low SMUG1 protein expression remains associated with poor survival (p < 0.01). In ER- cohort that received adjuvant chemotherapy, low SMUG1 protein expression is associated with improved survival (p = 0.043). Our study suggests that low SMUG1 expression may correlate to adverse clinicopathological features and predict response to adjuvant therapy in breast cancer.

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.

Evaluation of flap endonuclease-1 (FEN1) as a prognostic, predictive, and therapeutic target in breast (BC) and ovarian cancer (OVC)

1016

Background: FEN1 is a multifunctional protein with essential roles in long patch base excision repair (LP-BER), Okazaki fragment maturation during replication, resolution of tri-nucleotide repeat sequence-derived secondary structures, rescue of stalled replication forks, maintenance of telomere stability and apoptotic fragmentation of DNA. In the current study we have evaluated FEN1 as a prognostic, predictive and therapeutic target in BC and OVC. Methods: Clinico-pathological significance of FEN1 mRNA expression was evaluated in a BC training cohort [n=128], test cohort (n=249) and validated in a large cohort of 1,980 BC (METABRIC). Neural network analysis (NNA) was conducted to identify FEN1 interaction genes. FEN1 protein expression was investigated in three consecutive series of BC and OVC: 568 ER negative (ER- BC), 894 ER positive (ER+ BC) and 195 OVC cohorts. Pre-clinically, FEN1 deficient and proficient HeLa cell lines were investigated for chemotherapy sensitization. A high throughput screening (HTS) strategy was developed to identify FEN1inhibitors for therapeutic application. Results: FEN1mRNA overexpression is associated with adverse clinicopathological features such as high grade, high mitotic index, and triple negative (ps<0.0001). High FEN1 mRNA expression was highly significantly associated with PAM50 Her2, PAM50 Basal and PAM50 LumB (ps<0.0001) BC. FEN1 mRNA overexpression is associated with resistance to chemotherapy (p=0.019), endocrine therapy (p<0.0001) and independently with poor survival (p<0.0001). NNA revealed novel interaction genes with predominant roles in proliferation, cell growth, DNA repair, differentiation, invasion, migration, metabolism and apoptosis. FEN1 protein overexpression is significantly associated with aggressive clinico-pathological features and independently with poor survivals in ER+ BC, ER- BC and in OVC (ps<0.001). HTS assay has identified novel FEN1 inhibitors for therapeutic development. Conclusions: This is the first study to investigate FEN1 in BC and OVC. We provide confirmatory evidence that FEN1 is a promising biomarker as well as a therapeutic anti-cancer drug target for clinical application.

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.

A study of sperm-associated antigen 5 (SPAG5) in predicting response to anthracycline (ATC)/platinum chemotherapies (CT) in breast (BC) and ovarian cancers (OVC)

1098

Background: Recently TOP2A alteration was found to be a predictor for ATC-CT and our neural network analysis of BC gene expression array (GEA) data has revealed SPAG5 gene as a major hubs in both TOP2A and proliferation pathways. In this study the molecular and clinicopathological functions of SPAG5 was investigated in BC and OVC. Methods: (1) A series of 171 BC was evaluated for SPAG5 gene copy number (using aCGH) and mRNA expression (using GEA) which were validated in 5 independent databases. (2) The expression of SPAG5 protein was evaluated pre-clinically in BC and OVC cell lines and in both 40 normal breast tissues and a series of 1650 primary BC and was correlated to clinicopathological and other biomarkers. (3) The association between SPAG5 and response to CT was investigated in a) 350 ER negative BC treated with adjuvant ATC-CT, b) 250 BC treated with neoadjuvant (NEO-A)-ATC-CT, and c) 200 primary OVC treated with cisplatinum based adjuvant CT. Results: (1) 5% and 15% of the 171 BC showed amplification and gain of SPAG5 locus, respectively, at 17q11.2. SPAG5 mRNA expression displayed a significant correlation with its copy number (p< 0.0001). (2) 30% and 20% of ovarian and BC respectively, showed overexpression of SPAG5 protein (+). In BC, SPAG5+ at both mRNA and protein levels showed a significant association with aggressive phenotypes, high mitosis, ER-, high grade, p53 mutation and epithelial mesenchymal transition phenotypes (ps <0.0001). SPAG5 mRNA (+) was statistically associated with poor survivals (p<0.0001). (3) In ER- BC treated with adjuvant ATC-CT, SPAG5 negative (-)had 7-times higher risk of progression compared with SPRAG+ BC (p<0.0001). SPAG5+ BC received NEO-A-ATC based CT achieved 38% pathological complete response (pCR) vs. 6% of SPAG5- (p<0.0001). After controlling to other predictors for pCR, SPAG5 was an independent predictor (HR; 2.4; p=0.001). Similarly, SPAG5- OVCs were resistant to platinum (p<0.001) and independently associated with poor survival (p<0.001). Conclusions: SPAG5 is an important novel gene implicated in the survival of BC and OVC cells and its protein expression is an independent predictor for anthracycline/ cisplatinum CT.

HAGE (DDX43) protein expression as an independent biomarker of poor clinical outcome of breast cancer (BC) and potential as a therapeutic target for ER-negative BC

1013

Background: Recently, we have confirmed that HAGE is involved in promoting proliferation as assessed by increased thymidine incorporation and our preliminary results using shRNA to permanently knockdown HAGE expression also suggests the involvement of HAGE in tumor motility and metastasis. In this study we aimed to analyze the expression of HAGE in large well-characterized BC cohorts to determine its relationship with other clinico-pathological parameters and to investigate its prognostic value. Methods: HAGE protein expression was assessed in: a) 40 normal breast tissue (NBT), b) 60 invasive BCs and their matching NBT, c) BC cell lines, d) A series of 1650 consecutive cases of primary BC who treated with adjuvant CMF and/or endocrine therapies. Further validation was performed in 2 independent series of high risk ER- BC: a) 300 ER –BC who did not received any CT and b) 396 ER- BC treated with adjuvant anthracycline (ATC) based CT. Results: The NBT showed negative HAGE expression (HAGE-) throughout. HAGE overexpression (HAGE+) was observed in 10% of BC and was significantly associated with aggressive clinico-pathological features including: ER-, high grade and triple negative phenotypes. Moreover, HAGE+ expression showed an adverse outcome with a 2-4 fold increase in the risk of death, recurrence and metastases (ps<0.00001) compared to HAGE-; ps<0.0001. Using a multivariate Cox regression model including ER status, grade, size and tumour stage, HAGE expression was confirmed as a powerful independent prognostic factor (p<0.0001). The poor clinical outcome of HAGE+ was further confirmed in high risk (NPI>3.4) ER- patients who did not received any CT (p<0.0001). While, adjuvant CT either CMF or ATC had a positive impact on HAGE+/high risk ER- BC as HAGE+ had a similar risk of death, recurrence and distant metastases to HAGE- expression. Conclusions: This is the first report which shows HAGE to be a potential predictor for poor prognosis in BC patients, and may be an attractive novel target for molecular and vaccine therapy for those patients. A prospective trial of adjuvant chemotherapy/vaccine to confirm this finding is warranted.

Targeting XRCC1 (X-ray repair cross-complementing gene 1) deficiency in tumors for personalized cancer therapy

1014

Background: XRCC1 is essential for DNA base excision repair, single strand break repair and nucleotide excision repair. XRCC1 deficiency promotes genomic instability and may increase cancer risk. Methods: We evaluated XRCC1 immunohistochemically in early stage breast (n=2046), ovarian (n=157), gastric (n=140), colorectal (n=250) and pancreaticobiliary cancers (n=240). Pre-clinically, we evaluated a panel of XRCC1 deficient and proficient Chinese hamster ovary and human cancer cell lines. Double strand break repair (DSB) inhibitors targeting ATM (KU55933), DNA-PKcs (NU7441) and ATR (NU6027) were evaluated for synthetic lethality and cisplatin alone or in combination with DSB inhibitors for chemopotentiation. Results: In breast cancer,XRCC1 loss (16%) was associated with higher grade (p<0.0001), loss of hormone receptors (p<0.0001), presence of triple negative (p<0.0001) and basal like phenotypes (p=0.001). Loss of XRCC1 was associated with a 2-fold increase in risk of death and metastasis (p<0.0001) and independently with poor outcome (p<0.0001). In ovarian cancer, XRCC1 was positive in 44% of tumour and was significantly associated with higher stage (p=0.001), clear/endometroid type (p=0.015) and sub-optimal debulking (p=0.004). XRCC1 positive tumours were more resistant to platinum chemotherapy (p=0.0001). XRCC1 positivity conferred a 2 fold increase of risk of death (p=0.002) and independently associated with poor survival (p=0.002). In gastric cancers, XRCC1 was positive in 37% of tumours. This was significantly associated with high stage disease (p=0.001) and poor survival (p=0.001). Pre-clinically, KU55933, NU7441 and NU6027 were synthetically lethal in XRCC1 deficient compared to proficient cells as evidenced by DSB accumulation, G2/M cell cycle arrest and apoptosis. XRCC1 deficient cells were hypersensitive to cisplatin which was enhanced by DSB repair inhibitors compared to in proficient cells. Conclusions: This is the largest study to confirm the clinical significance of XRCC1 expression in solid tumours. XRCC1 deficiency in human tumours may be suitable for synthetic lethality application and exploited for cisplatin chemotherapy potentiation.

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.

Proposal for a modified grading system based on mitotic index and Bcl2 provides objective determination of clinical outcome for patients with breast cancer

We hypothesized that the interaction between mitotic index (M) and Bcl2 could accurately discriminate between low- and high-grade breast cancer (BC) and provide a more objective measure of clinical outcome than histological grade, especially for patients with intermediate histological grade (G2), small size or oestrogen receptor (ER)-negative cancers. A well-characterized series of 1650 BCs with long-term follow-up was subjected to immunohistochemical analysis for Bcl2. Mitotic index (M) was assessed according to Nottingham Grading System (NGS) guidelines: M1: < 10 mitoses; M2: 10-18 mitoses; M3: > 18 mitoses. Results were validated in an independent series of patients (n = 245) uniformly treated with adjuvant anthracycline-based chemotherapy. Subsequently, BCs were classified according to the combined M/Bcl2 profile and compared with NGS. Multivariate Cox regression models using validated prognostic factors demonstrated that the subgroups defined by M/Bcl2 profile remained significantly associated with patients' outcome but also performed better than lymph node status and tumour size. Incorporation of the M/Bcl2 profile into the Nottingham Prognostic Index (NPI) reclassified twice as many patients into the excellent prognosis group, potentially improving decision-making and sparing patients unneeded systemic adjuvant therapy. Patients with M2-3/Bcl2- and M3/Bcl2+ (high risk) had a two- to three-fold increased risk of recurrence when treated with either adjuvant hormone therapy or anthracycline-based chemotherapy compared with those with M1/Bcl2 ± and M2/Bcl2+ (low risk) [HR = 3.4 (2.8-5.6); p < 0.0001 and HR = 2.3 (1.2-4.3); p = 0.0009]. In conclusion, a grading system defined by mitotic counting and Bcl2 expression accurately reclassified patients with NGS-G2, small tumour size or ER-negative cancers into two groups: low risk (NGS-G1-like) versus high risk (NGS-G3-like) of BC mortality and recurrence, improving prognosis and therapeutic planning.

High frequency of coexistence of columnar cell lesions, lobular neoplasia, and low grade ductal carcinoma in situ with invasive tubular carcinoma and invasive lobular carcinoma

This study was undertaken to determine the morphologic features and frequency of putative precursor lesions involved in the development of some pure forms of special types and low grade breast carcinoma. We reviewed 147 successive tumor cases, comprising tubular carcinoma (TC); pure type (n=56) and mixed type (n=20), invasive lobular carcinoma (ILC); classic type (n=57), and tubulolobular carcinoma (TLC; n=14). The presence of preinvasive lesions including columnar cell lesions (CCLs), usual epithelial hyperplasia, ductal carcinoma in situ (DCIS), and lobular neoplasia (LN) was determined. Estrogen receptor and E-cadherin immunohistochemistry was performed. Ninety-five percent (95%) of pure TCs had associated CCLs with the majority showing flat epithelial atypia. Atypical ductal hyperplasia (ADH)/DCIS was present in 89% patients. Colocalization of CCL, ADH/DCIS, and TC was seen in 85% patients, all displaying the same cytologic-nuclear morphology in most cases. LN was seen in 16%. In ILC, 91% cases showed LN. CCL and ADH/DCIS were seen in 60% and 42% cases, respectively. E-cadherin was positive in TLC but reduced in TC and completely absent in ILC. In conclusion, our findings support the hypothesis that CCLs are associated with pure and mixed forms of TC, and that LN is involved in ILC development. Our observations suggest that these lesions represent family members of low grade precursor, in situ and invasive neoplastic lesions of the breast. Molecular studies are being performed to substantiate the hypothesis that tubular and lobular carcinomas have direct evolutionary links to CCLs and flat epithelial atypia.