Fig. 1

Immunohistological detection of infiltrating TIE2-expressing monocytes (TEMs), angiopoietins (left column: high density; right column: low density) in the tumor central area (TCA) of hepatocellular carcinoma (HCC) specimens. Arrows indicate positive staining and asterisks indicate microvessels. Scale bar, 50 μm. Therefore, the corresponding monocytes (i.e., TEMs) are visualized as cells that are double positive for CD14 and TIE2. This positivity in the immunohistology is seen as simultaneous red and brown staining (arrows). On the other hand, microvessels (i.e., endothelial cells) are positive only for TIE2 and are, thus, visualized as brown reactivity only (asterisks). a High density of TIE2⁺ monocytes in the TCA. HCC revealed a homogenous infiltration pattern of these cells with preference for the perivascular areas. b Low density of TIE2⁺ monocytes (arrows). c High angiopoietin-1 expression. d Low angiopoietin-1 expression