Expression of the Bcl-2 apoptotic marker in cats diagnosed with inflammatory bowel disease and gastrointestinal lymphoma

Abstract

Immunolabeling for the critical lymphocyte survival factor, Bcl-2, of intestinal biopsies from cats with histologic evidence of inflammatory bowel disease (IBD) or gastrointestinal (GI) lymphoma was evaluated to determine if expression differed significantly between these two disease processes. Immunolabeling for Bcl-2 was performed on small intestinal endoscopic or full thickness biopsy sections from 55 cats. Diagnosis of IBD, T-cell lymphoma or B-cell lymphoma was established previously. The percentage of infiltrating lymphocytes that were positively labeled for Bcl-2 was subjectively determined for each case. Eight cats were diagnosed with IBD and 47 cats with lymphoma. A significantly higher percentage of cells were positively immunolabeled for Bcl-2 in cats with GI lymphoma [median (range); 90 (5-95)%] compared with cats with IBD [60 (15-95)%] (P = 0.029). However, the overall degree of positive immunolabeling in both groups tended to be high. This over-expression of Bcl-2 may prove useful as a therapeutic target for IBD and GI lymphoma in cats.

Figure 1

Feline small intestine sample infiltrated by malignant T-cells. At least 95% of the transmurally infiltrating round cells demonstrated positive red nuclear immunolabeling for Bcl-2

Figure 2

Feline small intestine sample demonstrating inflammatory bowel disease. Approximately 50% of the infiltrating round cells in the mucosal lamina propria displayed red nuclear immunolabeling for Bcl-2. Occasional intraepithelial lymphocytes within the villi also demonstrate positive labeling