MP29-07 INVERSE RELATIONSHIP BETWEEN INSULIN RECEPTOR EXPRESSION AND FAVORABLE OUTCOMES IN PATIENTS WHO UNDERWENT RADICAL NEPHRECTOMY FOR RENAL CELL CARCINOMA

Abstract

INTRODUCTION AND OBJECTIVES: It has been reported that obesity increases the risk of renal cell carcinoma (RCC). Insulin, which regulates mitogenic effects as well as plasma glucose levels, has been linked with the development of cancer. We investigated the relationship between insulin receptor (IR) expression and favorable outcomes in patients who underwent radical nephrectomy for RCC. METHODS: pT1eT4 tumor specimens from 99 patients with RCC (clear cell, 81; papillary, 8; chromophobe, 4; sarcomatoid, 4; and Xp11.2 translocation, 1) were evaluated for IR expression and insulinlike growth factor 1 (IGF-1) receptor (IGF-1R) protein by immunohistochemistry. Serum insulin, C-peptide, and IGF-1 levels were measured by ELISA. Association between the biomarker expression and serum concentration, prognostic factors, and clinical outcomes were assessed. RESULTS: IR expression was high in 24 (24.3%) tumors, intermediate in 57 (57.5%), and low in 18 (18.2%). IGF-1R expression was high in 28 (28.3%) tumors, intermediate in 54 (54.5%), and low in 17 (17.2%). High IR expression was an independent predictor of favorable progression-free survival (p 1⁄4 0.017, Cox proportional hazards model). Overall survival of patients with RCC and high IR expression was significantly longer than that of patients with low-to-intermediate IR expression (p 1⁄4 0.031, logrank test). Serum insulin, C-peptide, and IGF-1 levels were not associated with favorable prognostic outcomes. CONCLUSIONS: In patients with RCC who underwent radical nephrectomy, high IR expression was an independent predictor of favorable outcome. The findings suggest that insulin signaling may play a role in the RCC progression.