Histopathology findings.

(A) Control animal recipient of BM cells transduced with parent MSCV vector; H&E stain (100 × magnification) (scale bar: 100 μm). (B)Dll4-overexpressing animal with a diffuse lymphoblastic infiltrate; H&E (10 ×). Inset: closeup of CD3⁺ T cells, ABC immunostain (400 ×). (C) Mesenteric lymph node from a control mouse showing normal cortical follicles, paracortical area, and medullary cords; H&E (100 ×). (D) Enlarged mesenteric lymph node from a Dll4-overexpressing mouse with diffuse lymphoblastic infiltration of the node (arrow denotes lymph node capsule) and perinodal adipose tissue; H&E (100 ×). (E) Liver from a control mouse with normal hepatic architecture; H&E (100 ×). (F) Enlarged liver from a Dll4-overexpressing mouse with lymphoblastic infiltration of the periportal areas (arrow) and sinusoids throughout the liver; H&E (100 ×). Animals were at 12 weeks after BMT.