Quantification of circulating microRNAs by droplet digital PCR for cancer detection

OBJECTIVE: Circulating cell-free microRNAs (miRNAs) which consist of short-sequence RNAs are released from cells into the blood stream and has emerged as new biomarkers in the clinical cancer diagnosis and treatment. For instance, ovarian cancer comprises one of the three major malignant tumor types in the female reproductive system. The mortality rate of this cancer is the highest among all gynecological tumors, with ovarian cancer metastasis constituting an important cause of death. Therefore, development of a diagnostic tool that enables the ovarian cancer diagnosis in earlier stages is urgent. RESULTS: We have described an efficient protocol for an accurate absolute quantification of circulating miRNAs in healthy and ovarian cancer serum samples. Our data showed that ddPCR methodology can accurately measure circulating miRNAs levels and that can be a useful tool in biomarkers discovery for ovarian cancer detection.