In this study, cfDNA concentration and tumor burden as determined according to the guidelines laid out by RECIST 1.1 for measurable lesions at baseline prior to 1st line treatment positively correlated in therapy naïve patients (Fig 2A) as well as cfDNA and CEA (Fig 2B), which is in line with previously reported data [28]. The gene discussed is CEACAM5; the disease is neoplasm.