Figure 2.

Gross and microscopic morphology of progressive and regressing Burkitt lymphoma tumors. (A–D) Tumor tissue from a mouse injected subcutaneously with CA46 Burkitt cells. (E–H) Tissue from a tumor induced by subcutaneous injection with CA46 Burkitt cells and subsequently injected with LCL (VDS line) weekly for 3 weeks. (I–L) Tissue from a tumor induced by subcutaneous injection with CA46 Burkitt cells and subsequently injected daily with human IP-10. (M–P) Tumor tissue from a mouse injected subcutaneously with murine IP-10-expressing CA46. (A, E, I, and M) Gross morphology of Burkitt tumors showing viable looking tumor tissue (A) and regressing tumors with extensive central necrosis surrounded by viable tumor (E, I, and M) (no magnification). (B, F, J, and N) microscopic morphology of Burkitt tumors extending to the epidermidis; in B viable-looking tumor tissue, and in F, J, and N the interface between necrotic (top) and viable (bottom) tumor tissue are shown. (C, G, K, and O) Higher power magnification of viable tumor tissue (C) and of the interface of necrotic (top) and viable (bottom) tumor tissue (G, K, and O). A prominent macrophage infiltration is noticeable in G. (D, H, L, and P) Higher power magnification of viable tumor tissue with patent capillaries (containing red cells) in D, and capillaries occluded with thrombi at various stages of reorganization (H, L, and P). (B, F, J, and N, ×5; C, G, K, and O, ×10; D, H, L, and P, ×20.)