[872] IMP-3 Is an Independent Prognostic Marker in Clear Cell Renal Cell Carcinoma

J Huang, P Elson, H Aydin, L Sercia, K Simmerman, B Rini, M Zhou. Cleveland Clinic, Cleveland, OH

Background: IMP-3, a member of the insulin-like growth factor II mRNA binding protein family, was recently implicated as promising prognostic marker for several human cancers including renal cell carcinoma. We validated the prognostic significance of IMP-3 with an independent cohort of patients (pts) with clear cell renal cell carcinoma (CCRCC).
Design: A tissue microarray including 582 clinically localized CCRCC treated surgically between 1988 and 2003 was immunostained with an anti-IMP3 antibody. The staining intensity (0/negative, 1+/weak, 2+/moderate or 3+/strong) and % of positive cells were correlated with other pathologic parameters, including T-stage, Fuhrman nuclear grade, presence of sarcomatoid differentiation and tumor necrosis, and clinical outcome data, including recurrence-free survival (RFS) and overall survival (OS).
Results: IMP-3 was positive in 56 pts (9.6%), including 14 (2.4%) 1+, 22 (3.8%) 2+, and 20 (3.4%) 3+. The mean % of tumor cells positive staining for staining was 30% (range, 2-100%). IMP-3 staining was significantly associated with all pathologic factors examined (nuclear grade, perinephric fat invasion, microscopic vascular invasion, T-stage, tumor size, and the presence of necrosis or a sarcomatoid element), p<0.003 in all cases. In both uni- and multi-variable analyses, IMP-3 intensity was found to be significantly associated with RFS and OS, p=0.0006 and 0.0008 respectively, as well as other known prognostic factors including Furhman grade (OS, p=0.001), T-stage (RFS, p<0.001) and tumor necrosis (RFS and OS, P<0.009).

Conclusions: We have validated IMP-3 as a promising prognostic predictor for CCRCC after nephrectomy in an independent cohort of patients. Future studies will be to investigate the molecular mechanism by which IMP-3 confers aggressive biological behavior.
Category: Genitourinary (including renal tumors)

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 112, Wednesday Morning


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