MDSC clinical assay for cancer detection and monitoring in renal cell carcinoma.

Abstract

TPS713 Background: Human Myeloid Derived Suppressor Cells (MDSCs) have gained recognition as a significant population of cells that arise in cancer patients to mediate immune tolerance. Some studies have shown MDSC concentrations to be associated with overall survival and response to therapy in renal cell carcinoma. MDSCs comprise a heterogenous population that are yet to be fully characterized. We have identified a set of biomarkers uniquely expressed by the suppressive human MDSC phenotype and have developed an assay targeted to these markers. MDSCs are potentially a relatively cheap and easily performed screening and monitoring tool in cancers. This study will examine how a proprietary clinical assay works in detecting and monitoring MDSCs in blood and urine samples from patients with localized or metastatic renal cell cancer. Methods: The pilot research trial will enroll 63 subjects in a 1:1:1 ratio in three groups, normal controls over age 40 without evidence of any malignancy, patients with metastatic disease and localized renal cell carcinoma prior to nephrectomy. This sample size provides 80% power to detect a 1SD difference in MDSC concentrations in these groups on an F test. Blood and urine samples will be drawn at baseline and at 4 months for comparison. The percent CD33+ HLA-DRlow HIF1a+, CD33+ HLADRlow C/EBPb+, CD11b+ HLA-DRlow HIF1a+, and CD11b+ HLA-DRlow C/EBPb+cells as a fraction of PBMC will be determined. Primary Outcome Measures will be 1. Change in MDSC levels in patients with known localized renal cell carcinoma who undergo surgical treatment. 2. Change in MDSC level in patients with known metastatic renal cell carcinoma who initiate systemic treatment and 3. The direction and magnitude of the changes compared with radiographically assessed tumor burden. Secondary outcome measures are to assess MDSC level measurements in urine cytology analysis at baseline and after treatment to determine whether the two tests correlate in any of the 3 groups of patients defined in this study. Conclusion: This pilot study will examine if a MDSC clinical assay works in detecting and monitoring MDSCs. Recruitment is open to patients at the USC Cancer center and LAC+USC medical center. Clinical trial information: NCT02664883.