Identification and validation of an 8-gene expression signature for predicting high-Fuhrman grade renal cell carcinoma.

526 Background: Clear cell renal cell carcinoma (ccRCC) is a malignancy with heterogeneous outcomes. Currently, renal mass biopsies are commonly employed to extract disease characteristics and aid prognosis. Although the pathological diagnosis of malignant disease is accurate in contemporary reports, the classification of Fuhrman grade using biopsy specimens is still far from promising. Our aim is to generate a signature biomarker to distinguish high grade ccRCC that could be readily applied to clinical biopsy samples. Methods: Using the Cancer Genome Atlas (TCGA) database, a gene expression signature was developed to distinguish high-grade (G3/4) from low-grade (G1/2) disease. The expression profile was further validated for performance and clinical usage in 283 frozen renal cancer samples and 127 ex-vivo renal mass biopsy samples, respectively. The area under curve (AUC) was used to quantify discriminative ability and was compared using the De-long test. Results: Using the development dataset, we identified a 24-gene signature for high-grade disease with an AUC of 0.884. After applied to the replication dataset, an eight-gene profile was defined and achieved an AUC of 0.823. The accuracy of 8-gene panel was maintained in the RMB samples (AUC = 0.821). Conclusions: Using a two-stage replication design, we validated an eight-gene expression signature for predicting high Fuhrman grade of ccRCC. This tool may help to reveal the characteristics of ccRCC biopsy specimens.