Figure 7. Effect of long-term plasma and cfDNA storage on cfDNA quality.

The workflow of this experiment is shown in Figure 5. Blood samples were obtained from five patients with advanced NSCLC carrying EGFR T790M mutation. The EGFR T790M test was performed just after blood collection (i) and 7 years after storage as cfDNA (ii). cfDNA immediately isolated from plasma was stored at −80° C for 7 years with two different isolation methods: silica membrane spin column (iii) and cellulose magnetic beads system (iv). The values of T790M AUM of these four conditions (i), (ii), (iii), and (iv) are shown for each of the five samples.