Tumor cell-associated TF expression is not required for tumor growth or tumor angiogenesis. (A) Weight of tumors formed 18 days after injection of 5 × 10⁵ TF^WT, TF^ΔTail, or TF^O tumor cells into the dorsal subcutis of wild-type C57Bl/6 mice (n = 9 for each tumor cell genotype). Note that there is no significant difference in tumor mass, regardless of the presence, absence, or form of tumor cell–associated TF. (B) Comparative analysis of vascular density in subcutaneous tumors harvested 18 days after injection of TF^WT, TF^ΔTail, or TF^O tumor cells. Tumor tissue sections (n = 3-4 per tumor cell genotype) were stained with an anti-CD31 antibody and vessels were enumerated within 10 200× fields. Note that no significant difference in vessel density was observed in any pair-wise comparison of cohorts. The error bars in (A) and (B) indicate the SEM. (C-F) Microscopic appearance of tumor sections prepared from primary tumors established with TF^WT, TF^ΔTail, and TF^O tumor cells. Representative TF^WT (C and E) and TF^O (D and F) tumors sections processed for hematoxylin/eosin staining (C and D) or processed for immunohistochemical detection of the endothelial cell marker, CD31 (brown precipitate) (E and F). The scale bars indicate 50 μm (C and D) or 100 μm (E and F).