[312] Biomarker Expression Can Identify Biologically Distinct Categories of Invasive Breast Cancer

JY Shim, R Zhou, PA Thompson, AM Brewster, JL Murray, ME Edgerton, N Karadag, ML Bondy, A Sahin. MD Anderson Cancer Center, Houston; Arizona Cancer Center, Tucson

Background: Tumor size, stage, lymph node status and histologic grade are significant prognostic factors in breast cancer. We sought to investigate the usefulness of a panel of biomarkers by correlating them with clinicopathologic parameters and outcome.
Design: Tissue microarrays from 1158 patients with stage I and II invasive breast cancer were constructed and immunohistochemical staining for ER, PR, HER2, P53, Ki-67, CK5/6, CK14, CK17, EGFR, Bcl-2, COX-2 and P27 were performed.
Results: The positive rates for ER, PR, HER2, P53, CK5/6, CK14, CK17, EGFR and COX-2 were 66%, 53%, 10%, 57%, 10%, 5%, 9%, 8% and 84%, respectively. The mean percentage of Bcl-2 was 70% and that of P27 was 62%. Ki-67 positivity was low in 61%, intermediate in 26% and high in 14%. Table1 summarizes the correlation between the biomarkers and clinicopathologic parameters. Many biomarkers were associated with each other. In univariate analysis, tumor size and stage were predictive of disease-free survival, while ER, CK14, EGFR, tumor size and stage were predictive of overall survival.

Table1.Correlation between markers and clinicopathologic parameters shown by P-value

	Size	Stage	Nuclear grade	Metastasis
ER	<0.0001	0.0001	<0.0001	0.043
PR	0.002	0.004	<0.0001	0.464
HER2	0.170	0.160	<0.0001	0.218
CK 5/6	<0.0001	0.0001	<0.0001	0.022
CK 14	<0.0001	0.004	<0.0001	0.039
CK 17	0.0003	0.003	0.014	0.060
EGFR	0.0008	0.002	<0.0001	0.217
P53	0.056	0.176	0.0002	0.415
COX-2	0.0003	0.588	<0.0001	0.819
Bcl-2	<0.0001	0.0001	<0.0001	0.081
P27	0.0003	0.020	<0.0001	0.047

Conclusions: Our large cohort of patients with long term follow-up confirms that evaluation of known biomarkers is necessary for all breast cancers. Current clinical practice might benefit from the addition of basal cytokeratins, EGFR, P53 and COX-2 to current panels.
Category: Breast

Monday, March 22, 2010 1:00 PM

Poster Session II # 67, Monday Afternoon