THBS1 and neoplasm: Strikingly, positive PPLF cytology was served as a gold standard, and the diagnostic value of THBS1 methylation in GC tissues, paired PPLF, and serum for the peritoneal dissemination of GC was determined based on the ROC curves, of which the Aζ value of the ROC curve was 0.8234 for tumor tissues (Figure 3A), 0.8331 for PPLF (Figure 3B), and 0.8053 for serum (Figure 3C) compared with positive PPLF cytology.