The prognostic significance of ctDNA in cancer progression and its response to treatment has been described in recent years.38,39 It has been found that ctDNA levels are elevated in the serum of patients with pancreatic cancer (PC) and appear to decrease after treatment.13 In addition, the current clinical application often detects the mutation of target genes within ctDNA, for example, Diehl F and his team analyzed the serum ctDNA of 18 colorectal cancer patients and found hotspot mutated genes, such as APC, KRAS, TP53, and PIK3CA. The gene discussed is KRAS; the disease is pancreatic neoplasm.