Fig. 1.

Study design. a Plasma samples from 86 patients with resectable gastric GEJ cancer, were collected at baseline, after one cycle of chemotherapy (CT), after preoperative CT and 2–4 weeks following surgical resection. Cell-free DNA was extracted from plasma prior to bisulfite conversion, and subsequently analyzed using a DNA methylation-specific ddPCR assay (TriMeth). Plasma samples were classified as ctDNA positive (detected) or ctDNA negative (not detected). b Consort diagram illustrating the patient and plasma selection process for ctDNA analysis. Figure created using BioRender.com. GEJ gastroesophageal junction; CT chemotherapy; ddPCR droplet digital polymerase chain reaction; ctDNA circulating tumor DNA, Me methylation