[183] Can GP88 Expression Serve as an Additional Surrogate Marker for Oncotype DX Recurrence Score?

Madhurima Koka, Lindsay B Goicochea, Ginette Serrero, Katherine Tkaczuk, Binbin Yue, Kimberly Tuttle, Olga B Ioffe. University of Maryland School of Medicine, Baltimore, MD; University of Maryland Greenebaum Cancer Center, Baltimore, MD; A&G Pharmaceutical Inc., Columbia, MD

Background: GP88 (progranulin) is an autocrine growth factor involved in survival, angiogenesis and cell migration. In estrogen receptor-positive (ER+) cells, GP88 overexpression is associated with resistance to Tamoxifen and Letrozole. High levels of GP88 expression in ER+ breast carcinoma have been reported to be associated with a 4-fold decrease in disease-free survival and a 2-fold decrease in overall survival. In this study, we investigated the correlation of GP88 expression in ER+ breast cancers with Oncotype DX recurrence score and other prognostic factors.
Design: Sixty-eight women ages 37-77 with ER+ invasive mammary carcinoma were studied. GP88 immunostaining was compared to routine clinicopathologic factors, PR, HER2/neu and Ki67 (by image analysis) and Oncotype DX (Genomic Health).
Results: The GP88 expression correlated with Oncotype Dx Recurrence score qw well as with Ki-67 index, tumor grade and stage. Age, HER2/neu and PR status did not correlate with GP88 expression.

GP88 expressionMean Ki-67 index (%)Mean Oncotype DX® Recurrence Score®pT1pT2Grade 1Grade 3
0/1+, 33 cases14.41627 (81%)6 (19%)7 (21%)4 (12%)
2+/3+, 25 cases25.8227 (28%)18 (72%)3 (12%)6 (24%)
p value0.030.030.0010.05

Conclusions: This is a first study to show that GP88, an important tumor aggressiveness marker, significantly correlates with Oncoype DX score and other tumor clinicopathologic parameters and prognostic markers. Further studies are underway to determine whether a combination of GP88 with other standard factors could be used instead of Oncotype DX Assay to predict outcome and determine management in ER+ breast cancers.
Category: Breast

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 13, Tuesday Afternoon


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