Immunohistochemical analysis of the distribution of B-FN in human and mouse grafted tumor models. Immunostaining of cryostat sections of F9 mouse teratocarcinoma allograft (A), N592 human small cell lung carcinoma xenograft (B), and SKMEL-28 human melanoma (C) using the antibody fragment L19. (D) A double staining of the SKMEL-28 human melanoma xenograft using the antibody fragment L19 (red staining) and an MoAb to mouse CD31, a marker of endothelial cells (brown staining). Scale bars: A, B, and D: 10 μm; C: 4 μm.