Fig. 4

PRTN3 expression in resected specimens. Immunohistochemical (IHC) analysis is performed using primary and metastatic specimens. Scale bar: 100 µm. a Representative images of PRTN3 expression in primary tumors. CES=4 × (intensity score − 1) + frequency score. The intensity scores are 0 (negative), 1 (weakly positive), 2 (moderately positive), and 3 (strongly positive). The frequency scores are 1 (5–24%), 2 (25–49%), 3 (50–74%), and 4 (75–100%). b Correlation between serum PRTN3 and CES levels. c and e Representative cases of PRTN3 expression in stromal cells of primary colorectal and metastatic liver specimens. The upper row shows the case with a few positive cells in the stroma. The lower row shows the case with many positive cells in the stroma. d and f Correlation between serum PRTN3 levels and number of PRTN3-positive cells in the stroma of primary and metastatic tumors, respectively. *P<0.05. Abbreviations: CES, composite expression score; HPF, high-power field; PRTN3, proteinase-3