168 THE JOURNAL OF UROLOGY ® Vol. 179, No. 4, Supplement, Sunday, May 18, 2008 three groups (p < 0.001). On multivariate analysis, CRP status as well CONCLUSIONS: The current result indicates that CRP response would be a prognostic factor for patient with mRCC. CRP would indicate relatively favorable prognosis, whereas failure of CRP use CRP response as a surrogate endpoint in treatment for patients with mRCC. Source of Funding: None 478 KIDNEY CANCER AND COMPETING CAUSES OF MORTALITY: AN AGE-BASED POPULATION STUDY David J Kaplan*, David A Kunkle, Ismail R Saad, Brian L Egleston, Robert G Uzzo. Philadelphia, PA. INTRODUCTION AND OBJECTIVE: Incidental detection of small renal masses (SRM) has led to an increased incidence of Renal patients. Recent data suggest that the development of metastatic disease is uncommon during active surveillance of SRMs over 3 to 5 years. Here we evaluate competing causes of non-cancer and cancer based death and compare these to death rates from RCC in age matched patients. METHODS: Mortality and survival rates in the United States were determined from the National Vital Statistics Reports. Patients on its relationship to RCC, non-RCC related cancers, and non-cancer causes of death. RESULTS: 5-year mortality data for 2,448,288 deaths in 2003 from all causes is nearly 25% in patients over 75 and 55% in patients over 85. In people more than 75 years old, the overall risk of death from RCC represents a very small percentage of mortality (0.24%), while in those 85+ years old only 0.12% will die of RCC. CONCLUSIONS: Mortality from RCC represents a small fraction of all causes of death in the United States. Five-year mortality from competing causes increases with increasing patient age. These data suggest that active surveillance of renal tumors may be appropriate for selected elderly and comorbid patients. Five-year Causes of Mortality in the United States Age Group 5-year Mortality from Kidney Cancer, (%) 5-year Mortality from Other Cancers, (%) 5-year Mortality from Non- Cancer Causes, (%) 5-year All- cause Overall Survival, (%) 55-64 years 0.04 1.6 2.9 95.4 65-74 years 0.08 3.6 7.1 89.2 75-84 years 0.12 5.7 18.7 75.5 85 years and over 0.12 6.2 48.2 45.4 Source of Funding: None 479 GENDER SPECIFIC CYTOGENETIC SIGNATURES CAN DISTINGUISH BETWEEN ONCOCYTOMA AND CHROMOPHOBE RENAL CELL CARCINOMA Tobias Klatte*, P Nagesh Rao, Michela de Martino, Jonathan W Said, Brian Shuch, Jeffrey LaRochelle, Fairooz F Kabbinavar, Arie S Belldegrun, Allan J Pantuck. Los Angeles, CA. INTRODUCTION AND OBJECTIVE: Differential diagnosis of oncocytoma and chromophobe renal cell carcinoma (CHRCC) can be problematic. Although Hale’s colloidal iron stain and other immunohistochemical tests are widely used, they all have limitations. Studies indicate that cytogenetic aberrations involving chromosomes prospective cohort with a particular focus on chromosome 1p and Y. METHODS: We prospectively collected cytogenetic data on (N0M0) CHRCC at our institution. For classical cytogenetic analysis, viable tumor samples were collected immediately after surgery, short- tumors (68%) including 26 oncocytomas and 17 CHRCCs showed an abnormal karyotype and form our principal study cohort. Karyotype aberrations between oncocytoma and CHRCC were compared using RESULTS: Among men (n=30), oncocytomas more frequently showed loss of 1p than CHRCC (69% vs. 7%, p=0.001), while a similar percentage had loss of Y (87.5% vs. 71%, p=0.378). Importantly, 62.5% of the oncocytomas but none of CHRCCs showed loss of both 1p and Y. Among women (n=13), in contrast, none of the oncocytomas exhibited both loss of 1p and sex chromosome. Loss of sex chromosome was infrequent (10% and 33%, respectively), and loss of 1p was actually more frequent in CHRCC than in oncocytoma (100% vs. 10%, p=0.014). Of note, we found one oncocytoma with acquired Robertsonian translocations and one CHRCC with ring chromosome 17, both of which have been never described before in adult renal tumors. We developed into clinical practice. CONCLUSIONS: CHRCC and oncocytoma have distinct cytogenetic signatures in men and women, creating the need for gender