Fig 1: Evaluation and validation of the principal DEPs. (A) ROC curves of the five proteins with the highest AUC values between CT and NT. (B) ROC curves of the unique 16 DEPs between the CT and NT. (C) ROC curves of selected potential markers between the CT and NT. (D) Box plots show the expression levels of specific DEPs across the CT, NT, and PT, as determined through Olink assays. The solid dots outside the box represent observations that are 1.5 times the interquartile range above and below the upper and lower quartiles. (E) Bar graphs illustrate the validation levels of WISP-1 (n = 23), ESM-1 (n = 18), TFPI-2 (n = 24), and HGF (n = 18) across the CT, NT, and PT, as determined through ELISA assays. (F) Bar graphs depict the expression levels of metastasis-associated proteins in CT from CRC patients, categorized into those with metastatic tumors (CT_M) and those without metastasis (CT_NM). * P < 0.05, ** P < 0.01, ****P < 0.0001, ns P > 0.05. NPX, normalized protein expression.