Development of a DNA methylation-based diagnostic signature to distinguish benign oncocytoma from renal cell carcinoma. Development of a DNA methylation-based diagnostic signature to distinguish benign oncocytoma from renal cell carcinoma

We profiled DNA methylation in fresh-frozen oncocytoma and chRCC tumors and tumor-adjacent adjacent normal tissue to identify a signature of differentially methylated CpG sites that robustly distinguish oncocytoma from chRCC. DNA methylation profiles were generated for renal oncocytomas (n=12), primary kidney chromophobes (chRCC) (n=8) and primary kidney clear cell carcinomas (ccRCC) (n=2). Also profiled were three oncocytic neoplasms of unclear pathological diagnosis, including two masses described as hybrid oncocytic/chromophobe type (n=2), and one mass described as hybrid oncocytic renal neoplasm. Also profiled were histologically normal adjacent kidney parenchyma tissue (NKP) from a subset of these patients, including NKP from oncocytoma (n=7), chRCC (n=5), ccRCC (n=1), hybrid oncocytic/chromophobe type (n=1), and hybrid oncocytic renal neoplasm (n=1) bearing kidneys (combined n=15 NKP). Overall design: DNA methylation arrays were used to profile genome-wide DNA methylation of renal neoplasms and normal tumor-adjacent tissues.