Apoptosis, bcl-2 expression, and p53 expression in gastrointestinal stromal/smooth muscle tumors.

The authors investigated the relations between outcome and apoptosis, immunohistochemical demonstration of bcl-2 protein, and immunohistochemical staining for p53 protein in patients with gastrointestinal stromal/smooth muscle tumors (GIST). Patients whose tumors demonstrated cellular apoptosis using the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL) assay had an improved survival over those whose tumors did not improve. In contrast, patients whose tumors demonstrated staining for bcl-2 protein had a decreased survival compared with those whose tumors did not demonstrate bcl-2. There was no relation between p53 immunoreactivity and survival. These results suggest that inhibition of apoptosis may be associated with malignant behavior in patients with gastrointestinal stromal/smooth muscle tumors.