Figure 1b depicts the mean Ct values resulting from all replicates containing PC−9 and NCI-H1975 tumor cells and from both replicates of the two healthy donors. As shown in Figure 1b, CDH5, CK19, PTHLH, and FAM83A were detected by qPCR in the spiked samples but not in the respective unspiked donor blood. Here, KRT19 is linked to neoplasm.