CEACAM5 and neoplasm: Immunohistochemical analysis with anti-PRSS3, anti-PRSS22, and anti-CEA antibodies applied to H&E(+) LNs demonstrated that a fraction of the tumor cells in the LNs, displayed positive staining for both PRSS3 (Figures 4A, B, D, E) and PRSS22 (Figures 4G, H, J, K).