Serum Extracellular Vesicles Double-positive for CD9 and CD147 or for CD9 and CD63 Decrease After Surgical Resection in Patients With Colorectal Cancer: Potential Biomarkers of Residual Tumor

Quantification of CD9⁺ CD63⁺ extracellular vesicles (EVs) in paired pre- and postoperative serum samples from patients with colorectal cancer. (A) Box-and-whisker plot; the center line indicates the median, the × symbol indicates the mean, and the box represents the interquartile range (25^th-75^th percentiles). Each dot represents an individual patient. (B) Paired changes in serum CD9⁺ CD63⁺ EV levels for each patient. Gray lines indicate cases classified as CD147⁻ by tumor immunohistochemistry, whereas black lines indicate cases classified as CD147⁺ by tumor immunohistochemistry (Table I). Statistical significance was assessed using the Wilcoxon signed-rank test (*p=0.0151).

CD147 immunohistochemistry in resected colorectal cancer tissue. Representative images of CD147 immunostaining using a CD147 antibody are shown. Cases were defined as CD147 positive when staining was observed in >5% of tumor cells (A, and B) and as CD147 negative when staining was observed in ≤5% of tumor cells (C) (Scale bar=100 μm).