Gross and microscopic morphology of progressive and regressing BL tumors. Female BALB/c nu/nu 6- to 8-week-old mice were injected subcutaneously with 107 BL cells. After tumor development, mice were observed or injected into the tumor with either LCL, human rMig, or human rIP-10. Tumors were removed in toto 5 to 6 weeks after the initial inoculation and processed for histology. (A through C) Tumor tissue from a mouse injected subcutaneously with CA46 Burkitt's cells. (D through F ) Tissue from a tumor induced by subcutaneous injection with CA46 Burkitt's cells and subsequently injected with LCL (VDS line) weekly for 3 weeks. (G through I) Tissue from a tumor induced by subcutaneous injection with CA46 Burkitt's cells and subsequently injected daily with formulation buffer (0.2 mL into the tumor). (J through L) Tissue from a tumor induced by subcutaneous injection with CA46 Burkitt's cells and subsequently injected daily with human rMig (400 ng/d into the tumor). (M through O) Tissue from a tumor induced by subcutaneous injection with CA46 Burkitt's cells and subsequently injected daily with human IP-10 (400 ng/d into the tumor). (A, D, G, J, and M) Gross morphology of Burkitt's tumors removed in toto with abstract epidermidis and dermis showing in (A) and (G) mostly viable looking tumor tissue with small and patchy areas of necrosis and in (D), (J), and (M) regressing tumors with extensive central necrosis surrounded by viable tumor (no magnification). (B, E, H, K, and N) Microscopic morphology (original magnification ×5) of Burkitt's tumors extending to the epidermidis; in (B) and (H) viable-looking tumor tissue; and in (E), (K), and (N) the abrupt interface between necrotic and viable tumor tissue. (C, F, I, L, and O) Higher power magnification (×20) of viable tumor tissue with patent capillaries (containing red blood cells) in (C) and (I) and capillaries occluded with thrombi at various stages of reorganization in (F ), (L), and (O).
