Single-stranded DNA (ssDNA) Labeling Index Is Related to Risk Grade in Patients with Gastrointestinal Stromal Tumors.

BACKGROUND/AIM: The main objective of the present study was to evaluate the significance of apoptosis in the Fletcher's risk classification for gastrointestinal stromal tumors (GISTs). MATERIALS AND METHODS: Apoptotic cells were identified by immunostaining for single-stranded DNA (ssDNA). We assigned each GIST to one of four risk groups: very low risk, n=32; low risk, n=53; intermediate risk, n=15; high risk, n=6). RESULTS: The mean ssDNA labeling index for each group was 8.0±44.2, 20.1±86.5, 18.7±38.6 and 5.7±5.7, respectively. Fletcher's risk classification for GISTs correlated significantly with the ssDNA labeling index (p=0.002). CONCLUSION: The ssDNA labeling index and Ki-67 labeling index were the most significant factors corresponding to the risk grade of GISTs. These findings suggest that the ssDNA labeling index might be useful for predicting aggressive biological behavior of GISTs.