Novel Diagnostic Tests for Renal Cell Carcinoma

Veterans Health Administration, Decatur PA

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Abstract

? DESCRIPTION (provided by applicant): Objectives. The objective of this proposal is to evaluate, in patients, two novel tests developed in our research laboratory for the detection of renal cell carcinoma (RCC). The primary objective is to rigorously determine sensitivity and specificity of the tests so that when the proposed work has been accomplished, evidence-based recommendations can be made for the use of the tests in specific patient populations and scenarios such as screening a healthy population, screening a high risk group such as patients with chronic kidney disease (CKD) or acquired cystic disease (ACD) and in the evaluation of radiologically detected renal masses. Research Plan. Two specific aims are proposed. In the first aim we will deploy the tests (quantitative determination of aquaporin-1 (AQP-1) protein in the urine and DNA-sequencing based detection of tumor- associated somatic mutations in the blood) in patients with known renal cancer (pre-op surgical cohort) and controls (healthy ambulatory population and individuals with CT scans showing no renal masses). In this way we will compare the new diagnostic tests' performance to gold standard diagnostic tests (tissue diagnosis for the positive controls and negative CT for the negative controls). In the second aim we will use the tests to screen patients seen in the Atlanta VA Renal Clinic that have CKD and abnormal screening ultrasounds, a high risk group. Methods. The urine AQP-1 test has been fully developed in a CLIA lab (Emory University Hospital clinical laboratory) and is a novel quantitative ELISA assay that is performed on proteins purified from urine. The analytic measurement range (AMR) is 0.25-16.0 ng/ml and is normalized to urine creatinine levels post- analytically. Preliminary data presented in this application demonstrate that all RCC urines tested to date are robustly positive while all healthy negative controls are below the AMR. The detection of tumor-derived DNA in the blood is performed by isolating DNA from patient plasma and then PCR amplifying the complete exonic sequence of 14 genes known to be mutated in RCC followed by deep sequencing using the Illumina platform, also established in a CLIA certified laboratory. Preliminary data demonstrates that all RCC tumor tissue sequenced in this manner demonstrates somatic mutations in at least one of the 14 genes and that 100% of evaluable patients had somatic mutations detected in the blood. Clinical Relevance. There is no laboratory test for RCC. Clinical outcome of RCC is essentially completely dependent on the stage at which the disease is detected with survival in excess of 95% for those tumors diagnosed at the earliest stage (small cancer confined to the renal capsule) compared to 5% or less once metastatic. The ultimate clinical translation of these tests would be to drastically alter the stage at which RCC is diagnosed thereby significantly decreasing morbidity and mortality from this disease that currently claims the lives of over 13,000 patients per year. This is especially relevant to veterans' health since hundreds of thousands of Marines and their families were exposed to TCE, a chemical degreasing agent, at Camp Lejeune (and many other Air Force and Marine bases) and the CDC has determined that these individuals are at significantly increased risk of developing RCC and that the Veterans Affairs health system is responsible for caring for these individuals. The development of screening tests for RCC within the VA system could be seen as particularly responsive to this congressionally directed mandate.