Azathioprine does not reduce adenoma formation in a mouse model of sporadic intestinal tumorigenesis

Figure 2 Azathioprine treatment results in the development of splenic T cell lymphomas. A: Representative image of vehicle and azathioprine treated mice showing splenic enlargement and discolored liver and kidneys in azathioprine treated animals; B: Representative photomicrographs of the morphology of the splenic infiltrates. The images show a highly atypical and pleomorphic population of lymphocytic blast-like cells with prominent variation in nuclear size and contour (left panel), atypical mitoses (middle panel, top right) and admixed giant cells (right panel); C: Splenic architecture. Peri-arteriolar B and T cell areas are preserved (B220 and Cd3 top panel), while the red pulpa is effaced by a Cd3 positive atypical infiltrate, diagnostic of T-cell lymphoma; D: Ki67 staining shows limited proliferative activity in pre-existent germinal centers; the surrounding atypical infiltrate demonstrates a nearly 100% labeling index. β-catenin does not show nuclear labeling in either genotype.