Prediction of Clear Cell Renal Cell Carcinoma by Integrity of Cell-free DNA in Serum

Abstract

To hypothesize that serum cell-free DNA integrity may be clinically useful for prediction of clear cell renal cell carcinoma (cRCC). The integrity of cell-free DNA released from cancer cells was different from that released from apoptotic cells. We collected peripheral blood samples from 78 patients before surgery; among these patients, 22 with tumor, both pre- and postoperation, and 42 controls without tumor. After the column extraction of DNA, we performed conventional polymerase chain reaction using different sizes of primers (size of products: 109, 193, 397, and 456 bp) of the housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase for measurement of serum cf-DNA integrity. Age and gender were not associated with cf-DNA integrity in controls (P = .136 and P = .345). Among the cRCC patients, we observed no significant association between cf-DNA integrity and gender, age, tumor grade (P = .510, P = .618 and P = .052), except tumor stage and size (P = .001 and P = .001). All specimens contained 109 bp products. The 193 bp product was detected in 75 of 78 cRCCs and 37 of 42 controls (P = .091), 21 of 22 patients preoperation and 19 of 22 postoperation (P = .294). The 397 bp product was detected in 71 of 78 cRCCs and 0 of 42 of controls (P = .001), 18 of 22 patients preoperation- and 7 of 22 postoperation (P = .003). The 456 bp product was detected in 69 of 78 of cRCCs and 0 of 42 of controls (P = .001), 18 of 22 preoperation and 3 of 22 postoperation (P = .002). Serum cf-DNA integrity may be a potential tool for the detection of clear cRCC.