A20 leukemia cells do not traffic to the colon. (A) Lethally irradiated Balb/c mice were administered 5 × 105 A20-luc cells and then transplanted the next day with B6 BM cells. Serial BLI studies were performed, and mice were killed 20 days after transplantation when leukemic dissemination was widespread. (B) BLI of individual organs, specifically the spleen (S), liver (L), lung (Lu), small intestines (SI), stomach (St), and colon from a representative mouse with disseminated A20 leukemia demonstrating tumor involvement in the spleen, liver, lung, stomach, and small intestines but not in the colon. (C) Pathologic examination of the same tissues that were imaged in panel B. In the liver, there is extensive leukemic infiltration around the portal triads (arrows). Leukemia cells are present in the interstitium of the lung and exhibit perivascular cuffing (arrows), and there is effacement of the red and white pulp by leukemia cells in the spleen. A20 cells are also present in the Peyer patches of the small intestines and extend into adjacent villi. Nodal tissue (solid arrow) that was contiguous to the duodenum (hatched arrow, Brunner glands) was observed to be replaced with leukemia cells as well. Leukemia was not detectable in the colon. One representative animal of 11 individual mice is shown in panels B and C. Images were obtained with an Olympus DP70 digital camera and an Olympus BX45 microscope with a 40×/0.75 NA lens.