Figure 3

(A–D) Neoplastic emboli (asterisks) within vascular channels (arrows) of both squamous cell carcinoma (two tumour nests infiltrating the stroma are also present on the right of the Figure) (A) and adenocarcinomas (B). Tumour emboli are strongly immunoreactive for fascin, even when the remainder tumour is negative for the marker (A, inset). In a case of adenocarcinoma, the same sinusoidal space, engulfed by tumour cells (asterisks), is delimited by CD34-positive endothelial cells (black triangles) and strongly reacts for fascin (C). Double immunostaining for fascin (red) and Ki-67 antigen (black–brown) shows that highly proliferating tumour cell foci (asterisks) are downregulating fascin expression, whereas adjacent neoplastic nests show either lower proliferative activity (black triangles) or strong immunoreactivity for fascin (D). (A–D: IM20 monoclonal antibody; in D, also Mib-1 monoclonal antibody. Immunoperoxidase staining was performed with diaminobenzidine to obtain a black–brown end product (A–D) or amino-ethylcarbazole to obtain a red end product (D), and then counterstained with haematoxylin. Scale bars are reported in the bottom on the left of every panel.)