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 expression||Mean Ki-67 index (%)||Mean Oncotype DX® Recurrence Score®||pT1||pT2||Grade 1||Grade 3|
|0/1+, 33 cases||14.4||16||27 (81%)||6 (19%)||7 (21%)||4 (12%)|
|2+/3+, 25 cases||25.8||22||7 (28%)||18 (72%)||3 (12%)||6 (24%)|