In contrast, Cohen et al. detected KRAS mutation in 66 of 221 (30%) of cfDNA in patients with resectable PDAC (Stage I and II) but in only 1 of the 182 plasma samples from the control patients without known cancer using PCR-based assay that could simultaneously assess the two codons (codon 12 and 61), called the “Safe-Sequencing System” [28]. This evidence concerns the gene KRAS and cancer.