Significance of p53 expression in gastrointestinal stromal tumors

Background/Aims: Gastrointestinal stromal tumors are non-epithelial tumors originating from the gastrointestinal tract walls. They expose a wide spectrum of histological properties from benign to poorly differentiated malignant tumors. Methodology: In this study 41 cases of gastrointestinal stromal tumors were reviewed for p53 expression using immunohistochemical stains. Immunoreactivity properties of the tumors were compared to prognostic factors such as mitotic index, tumor size, tumor site, presence of necrosis, mucosal invasion, proliferative index, telomerase activity, hemorrhage, cellularity, and histological pattern. Results: There was a significant difference in positive immunostaining of three case groups (12.2% in benign, 19.5% in borderline, and 68.3% in malignant group). Statistical analysis revealed a statistically significant positive correlation between p53 immunostaining properties and tumor size (p=0.01), mitotic index (p=0.05), cellularity (p=0.042), and diagnosis (p=0.01). Conclusions: We conclude that p53 expression may be a useful tool in classifying and predicting the prognosis of gastrointestinal stromal tumors as it is well correlated with tumor size, mitotic index, cellularity, and diagnosis according to our study results.