Qualification and quantification of plasma cell-free DNA after long-term storage conditions in patients with benign prostatic hyperplasia (BPH): A pilot study

Objectives: Free DNA is used as a cancer biomarker due to its low cost, high applicability, and fast, reliable results compared to invasive methods. This study aimed to evaluate the quantification of plasma-free DNA after long-term storage conditions and perform qualification through single nucleotide polymorphism (SNP) screening based on this DNA. Methods: Plasma-free DNA samples were quickly isolated from the peripheral blood of both the benign prostatic hyperplasia (BPH) and control group participants and then maintained at -80 °C for four years. Upon thawing, first, free DNA was purified and fluorometric measurements were taken to determine the amount of DNA. Subsequently, the rs6983267, rs12628, and rs1799939 SNPs were screened in the CCAT2, HRAS, and RET genes, respectively. Results: Significant results were obtained from the fluorometric measurements in terms of single-stranded DNA (ssDNA) (p<0.001). However, there was no significant difference in SNPs rs6983267, rs12628, and rs1799939 in the BPH group compared to the healthy individuals. Conclusions: The data show that fluorometric ssDNA measurements are suitable for quantifying free DNA. The fact that SNP screening can be done successfully in both healthy people and BPH patients suggests that plasma-free DNA can be stored in the laboratory under appropriate conditions. © 2022 the author(s), published by De Gruyter, Berlin/Boston.