Immunohistochemistry for tissue factor (TF) in a human pterygium and normal conjunctiva. Left panels are H&E staining and right panels are TF immunoreactivity in two representative cases of a pterygium. TF is expressed in the cytoplasm of basal (B; red arrow head), suprabasal (B; blue arrow head), and superficial cells (A; black arrow head). In the normal conjunctiva, however, immunoreactivity for TF is not detected (C). The scale bar represents 50 μm.Tissue factor expression in human pterygium. Ando R, Kase S, Ohashi T, Dong Z, Fukuhara J, Kanda A, Murata M, Noda K, Kitaichi N, Ishida S - Molecular vision (2011). Not Altered. CC.