Diagnostic Value of Circulating Cell-free DNA in Patients With Papillary Thyroid Cancer

Aim: We investigated whether the occurrence and development of papillary thyroid cancer (PTC) might be predicted using levels of circulating cell-free DNA (cfDNA). Materials and Methods: The peripheral blood samples were collected from 68 patients with PTC, 31 patients with nodular goiter (NG), and 86 healthy controls (HC). The concentration of cfDNA was measured by qPCR using three primer sets: /i-actin99, /i-actin394 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in plasma samples. Results: It was demonstrated that plasma /i-actin99 and /i-actin394 in the PTC group were significantly higher compared to HC (p<0.05 and p<0.001, respectively). The cfDNA integrity index was significantly higher in the PTC patients compared to HC and NG (p<0.001, p<0.05, respectively). The cfDNA concentration in the NG group was significantly higher than in the PTC (p<0.05 and p<0.001, respectively). Moreover, in most PTC patients with suppressed thyroglobulin, the /i-actin394 and cfDNA integrity index was significantly decreased after surgery (p<0.05 and p<0.001, respectively). ROC analysis revealed that cfDNA integrity index can be used as a potential marker in distinguishing PTC from HC (AUC 0.901, p<0.001) and NG (AUC 0.629, p<0.05). Conclusion: Increased concentration of cfDNA /i-actin99 and /i-actin394 may be a valuable biomarker that differentiates PTC patients from HC. Also, an increased cfDNA integrity index may be a suitable parameter which differentiates PTC patients from NG and HC.