Fig. 4.

Panel A: Colon cancer cells infected by JC virus were used as a positive control, of which 20–30% cells were positive. (grade III); Panel B, C, D: These photomicrographs show immunohistochemical staining for JCV T-Ag in gastric tumor tissue samples. B. Tumor sample without expression of T-Ag. C. a weak and focal positive nuclear staining can be observed in the nuclei of tumor cells (shown in brown; grade I) D. positive staining in the nuclei of tumor cells (grade II); Panel E: Positive staining of grade I in the nuclei of endothelial cells of healthy mucosa surrounding a gastric adenocarcinoma. Original magnification ×400.