Annual Meeting Proceedings Part 1 - American Society of Clinical ...
Annual Meeting Proceedings Part 1 - American Society of Clinical ...
Annual Meeting Proceedings Part 1 - American Society of Clinical ...
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1040 General Poster Session (Board #19G), Sat, 8:00 AM-12:00 PM<br />
Frequency <strong>of</strong> TLE3 overexpression in breast carcinoma subtypes including<br />
a large cohort <strong>of</strong> triple-negative patients. Presenting Author: Gargi D. Basu,<br />
Caris Life Sciences, Phoenix, AZ<br />
Background: The taxanes are an important class <strong>of</strong> agents for the treatment<br />
<strong>of</strong> a broad range <strong>of</strong> malignancies including breast cancer. They improve<br />
survival in patients with early stage and metastatic breast cancer. Transducin-like<br />
enhancer <strong>of</strong> split 3 (TLE3) is a transcriptional repressor which<br />
influences growth and microtubule stability and its expression has been<br />
implicated in response to taxane therapy in breast cancer. We investigated<br />
the tumor expression <strong>of</strong> TLE3 in breast cancer patients, including a large<br />
cohort <strong>of</strong> the triple negative subtype. Methods: We analyzed TLE3 (M-201),<br />
ER(1D5), PR(PgR636) and HER2/neu(Polyclonal) expression by immunohistochemistry<br />
in 978 breast cancer patients. Immunoreactivity was<br />
assessed by scoring the percentage <strong>of</strong> cells stained in each field and by the<br />
intensity <strong>of</strong> staining. Results: To sub-classify the 978 breast cancer<br />
patients, we utilized hormone receptors (ER and PR) and HER2 expression/<br />
amplification. Overall, 36% <strong>of</strong> the total breast cancer patients were<br />
hormone receptor positive, 15% were HER2 positive and 49% were triple<br />
negative. The percentage <strong>of</strong> triple negative patients was higher in our<br />
cohort, given the fact that molecular pr<strong>of</strong>iling services are used more<br />
frequently for this subtype. A total <strong>of</strong> 477 patients were triple negative <strong>of</strong><br />
which 61% stained positive for TLE3 expression. Of the 150 HER2 positive<br />
patients, 73% stained positive for TLE3 expression as compared with 82%<br />
TLE3 positivity in the 351 hormone receptor positive patients. By pairwise<br />
comparison, the hormone receptor positive vs triple-negative subtype<br />
showed the highest statistical significance in ratios <strong>of</strong> TLE3 positives (p<br />
�2.5e-10). Conclusions: Our results show that TLE3 is over-expressed in<br />
the majority <strong>of</strong> HER2 positive and hormone receptor positive breast cancer<br />
patients. Interestingly, the frequency <strong>of</strong> over-expression <strong>of</strong> TLE3 was lowest<br />
in the triple negative subtype thereby making it more important to identify<br />
those patients in this group who are most likely to respond to taxanes prior<br />
to therapy. To our knowledge, this is the first study providing a comprehensive<br />
review <strong>of</strong> TLE expression in breast cancer subtypes.<br />
1042 General Poster Session (Board #20A), Sat, 8:00 AM-12:00 PM<br />
Preclinical evaluation <strong>of</strong> PARP inhibition in breast cancer: Comparative<br />
effectiveness <strong>of</strong> olaparib and iniparib. Presenting Author: Maura B. Cotter,<br />
School <strong>of</strong> Medicine and Medical Science, University College Dublin,<br />
Dublin, Ireland<br />
Background: The main function <strong>of</strong> PARP1 is repair <strong>of</strong> single-strand DNA.<br />
Phase I/II clinical trials have shown that the PARP inhibitor, olaparib has<br />
efficacy in BRCA1/2-related breast cancer. Due to the similarities between<br />
BRCA1/2-associated and triple negative breast cancer (TNBC), we hypothesise<br />
that TNBC may also be sensitive to PARP inhibition. In order to assess<br />
this we addressed the effects <strong>of</strong> 2 PARP/PARP-like inhibitors, on a panel <strong>of</strong><br />
breast cancer cell lines. Methods: PARP1 was measured by immunohistochemistry<br />
in 101 TNBC and 116 non-TN cancers. Comparative growth<br />
inhibitory capacity <strong>of</strong> olaparib and iniparib was evaluated using cell<br />
viability (MTT) and colony formation assays in 12 breast cancer cell lines<br />
(TN�7, non-TN�5). Results: Using immunohistochemistry, PARP1 staining<br />
was predominantly nuclear with some cytoplasmic staining. High<br />
staining intensity for PARP1 was found more frequently in ER-negative (p<br />
� 0.001), in high grade (p � 0.013) and in Ki67-positive ( p � 0.003)<br />
samples. Potentially important was the finding that high PARP1 staining<br />
intensity was detected more frequently in TN than non-TN samples (p �<br />
0.0001). IC50 concentrations across 12 cell lines ranged from 3.7-31 �M<br />
for olaparib and 13-70 �M for iniparib. No difference in sensitivity was<br />
observed between the TN and non-TN cell lines (by MTT). Olaparib also<br />
reduced the ability <strong>of</strong> cells to form colonies with IC50 values ranging from<br />
�0.01-2.5 �M. Addition <strong>of</strong> the CDKI inhibitor CDK1i (Calbiochem) to<br />
olaparib resulted in formation <strong>of</strong> significantly fewer colonies compared with<br />
either inhibitor alone, in a cell line dependent manner. Conclusions: Our<br />
results suggest that although PARP1 is expressed in the majority <strong>of</strong> breast<br />
cancer, significantly higher staining intensity was found in TN than non-TN<br />
samples. Furthermore, our work suggests that olaparib is a more potent<br />
inhibitor <strong>of</strong> the in vitro growth <strong>of</strong> breast cancer cells than iniparib.<br />
Combined inhibition <strong>of</strong> PARP1 with olaparib and CDK1 with CDK1i may be<br />
a way forward for the treatment <strong>of</strong> TNBC. Acknowledgement: The authors<br />
thank SFI (SRC award, 08/SRC/B1410 MTCI) for funding this work.<br />
Breast Cancer—Triple-Negative/Cytotoxics/Local Therapy<br />
59s<br />
1041 General Poster Session (Board #19H), Sat, 8:00 AM-12:00 PM<br />
Epigenetic aspects <strong>of</strong> triple-negative in patients with breast cancer.<br />
Presenting Author: Joaquina Martínez-Galan, Medical Oncology Department,<br />
Hospital Universitario Virgen de las Nieves, Granada, Spain<br />
Background: Identification <strong>of</strong> gene expression-based breast cancer subtypes<br />
is considered a critical means <strong>of</strong> prognostication. Genetic mutations<br />
along with epigenetic alterations contribute to gene-expression changes<br />
occurring in breast cancer. However, the reproducibility <strong>of</strong> differential DNA<br />
methylation discoveries for cancer and the relationship between DNA<br />
methylation and aberrant gene expression have not been systematically<br />
analysed. The present study was undertaken to dissect the breast cancer<br />
methylome and to deliver specific epigenotypes associated with particular<br />
breast cancer subtypes. Methods: By using Real Time QMSPCR SYBR green<br />
we analyzed DNA methylation in regulatory regions <strong>of</strong> 107 pts with breast<br />
cancer and analyzed association with prognostics factor in triple negative<br />
breast cancer and methylation promoter ESR1, APC, E-Cadherin, Rar B<br />
and 14-3-3 sigma. Results: We identified novel subtype-specific epigenotypes<br />
that clearly demonstrate the differences in the methylation pr<strong>of</strong>iles <strong>of</strong><br />
basal-like and human epidermal growth factor 2 (HER2)-overexpressing<br />
tumors. Of the cases, 37pts (40%) were Luminal A (LA), 32pts (33%)<br />
Luminal B (LB), 14pts (15%) Triple-negative (TN), and 9pts (10%)<br />
HER2�. DNA hypermethylation was highly inversely correlated with the<br />
down-regulation <strong>of</strong> gene expression. Methylation <strong>of</strong> this panel <strong>of</strong> promoter<br />
was found more frequently in triple negative and HER2 phenotype. ESR1<br />
was preferably associated with TN(80%) and HER2�(60%) subtype. With<br />
a median follow up <strong>of</strong> 6 years, we found worse overall survival (OS) with<br />
more frequent ESR1 methylation gene(p�0.05), Luminal A;ESR1 Methylation<br />
OS at 5 years 81% vs 93% when was ESR1 Unmethylation. Luminal<br />
B;ESR1 Methylation 86% SG at 5 years vs 92% in Unmethylation ESR1.<br />
Triple negative;ESR1 Methylation SG at 5 years 75% vs 80% in unmethylation<br />
ESR1. HER2;ESR1 Methylation SG at 5 years was 66.7% vs 75% in<br />
unmethylation ESR1. Conclusions: Our results provide evidence that<br />
well-defined DNA methylation pr<strong>of</strong>iles enable breast cancer subtype<br />
prediction and support the utilization <strong>of</strong> this biomarker for prognostication<br />
and therapeutic stratification <strong>of</strong> patients with breast cancer.<br />
1043 General Poster Session (Board #20B), Sat, 8:00 AM-12:00 PM<br />
Molecular characteristics and metastasis predictor genes <strong>of</strong> triple-negative<br />
breast cancer. Presenting Author: Wen-Hung Kuo, Department <strong>of</strong> Surgery,<br />
College <strong>of</strong> Medicine, National Taiwan University, Taipei, Taiwan<br />
Background: Triple-negative breast cancer(TNBC) is a subtype <strong>of</strong> breast<br />
cancer with aggressive tumor behavior and distinct disease etiology. Due to<br />
the lack <strong>of</strong> an effective targeted medicine, treatment options for triplenegative<br />
breast cancer are few and recurrence rates are high. Although<br />
various multi-gene prognostic markers have been proposed for the prediction<br />
<strong>of</strong> breast cancer outcome, most <strong>of</strong> them were proven clinically useful<br />
only for estrogen receptor-positive breast cancers. Reliable identification <strong>of</strong><br />
triple-negative patients with a favorable prognosis is not yet possible.<br />
Methods: Clinicopathological information and microarray data from 157<br />
invasive breast carcinomas were collected at National Taiwan University<br />
Hospital from 1995 to 2008. Gene expression data <strong>of</strong> 51 triple-negative<br />
and 106 luminal breast cancers were generated with oligonucleotide<br />
microarrays. A prognostic 45-gene signature for triple-negative breast<br />
cancer was identified using Student’s t test and receiver operating<br />
characteristic analysis. Results: Hierarchical clustering analysis revealed<br />
that the majority (94%) <strong>of</strong> triple-negative breast cancers were tightly<br />
clustered together carrying strong basal-like characteristics. A novel<br />
45-gene signature giving 98% predictive accuracy in distant metastasis<br />
recurrence was identified in our triple-negative patient cohort. External<br />
validation <strong>of</strong> the prognostic signature in an independent microarray dataset<br />
<strong>of</strong> 59 early-stage triple-negative patients also obtained statistical significance<br />
(hazard ratio 2.29, 95% CI 1.04-5.06, Cox P � 0.04), outperforming<br />
five other published breast cancer prognostic signatures. The prognostic<br />
signature was statistically predictive with the node-negative triple-negative<br />
patients in the validation cohort. Conclusions: The 45-gene prognostic<br />
signature identified in this study revealed that TGF-� signaling in immune/<br />
inflammatory regulation may be critically involved in distant metastatic<br />
invasion <strong>of</strong> TNBC. The 45-gene signature, if further validated, may be a<br />
clinically useful tool in risk assessment <strong>of</strong> metastasis recurrence for<br />
early-stage triple-negative patients.<br />
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