Elevated serum-circulating RNA in patients with conventional renal cell cancer

Reliable serum biomarkers for differential diagnosis of conventional renal cell carcinoma (RCC) are highly desirable. Recent studies have confirmed the stability of circulating RNA in serum of cancer patients. The purpose of our study was to evaluate whether the amounts of circulating RNA could discriminate between conventional renal cancer patients and healthy individuals as a tumor marker.

A total of 71 patients with conventional RCC, 12 with renal oncocytomas and 44 healthy individuals entered into this study. Serum samples were taken and subjected to RNA extraction. The amount of RNA was quantified spectrophotometrically. Additionally, 9 serum samples from conventional RCC were also studied one week after nephrectomy. Diagnostic performance of RNA concentration was calculated through the receiver operating characteristic (ROC) curve to distinguish between conventional RCC and healthy individuals.

The mean level of RNA in conventional RCC (1414.19 +/- 91.95 ng/ml) was significantly higher than that in healthy individuals (520.49 +/- 39.75 ng/ml, p<0.0001) and these with renal oncocytomas (560.71 +/- 69.54 ng/ml, p<0.0001). Among the conventional RCC, there was no significant difference in circulating RNA levels in terms of tumor stage, grade or size. The area under the ROC curve was 0.956 (95% confidence interval, 0.923 to 0.989), indicating an acceptable sensitivity and specificity as a tumor marker. For conventional RCC, the RNA level was reduced significantly (p<0.0001) one week after nephrectomy.

The data suggest that elevated circulating RNA may be a valuable diagnostic tool for discriminating conventional RCC patients from normal individuals or from these with renal oncocytoma. Elevated serum circulating RNA provides a new research area as biomarker for the diagnosis of conventional RCC.