mutations using circulating cell-free DNA (cfDNA). It is well known that, unlike invasive tissue biopsy, one advantage of liquid biopsies is the evaluation of cancer-related gene mutations through blood sampling, which is a minimally invasive technique [1-4]. In addition, tissue biopsies are dif cult to perform repeatedly, and complications related to the procedure may occur depending on the site of the biopsy organ [5-7]. Above all, tumor heterogeneity is a signi cant challenge when detecting genetic alteration of tumors by tissue biopsy [5, 8, 9]. In contrast, liquid biopsy can be performed easily and repeatedly through blood collection. Since DNA is released into the blood vessels from the tumor tissue, another advantage of liquid biopsies is that it can reect the real-time genetic characteristics of the tumor [5-9]. The cfDNA is rapidly degraded by nucleases in circulating blood [10, 11], and delayed plasma separation can lead to contam