Clinicopathological and Prognostic Significance of Expression of B-Cell-Specific Moloney Murine Leukemia Virus Insertion Site 1 (BMI-1) Gene and Protein in Gastrointestinal Stromal Tumors

BACKGROUND: Gastrointestinal stromal tumor (GIST) is an uncommon visceral sarcoma that arises predominantly in the gastrointestinal tract. Since GISTs are encountered infrequently and inflexible to traditional therapy, the aim of the present study was to explore the correlation of B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI-1) mRNA and BMI-1 protein levels with the clinicopathological characteristics and prognosis significance of GISTs. MATERIAL/METHODS: GIST tissues and normal tissues were collected from 156 patients who had undergone surgical treatment. RT-qPCR and immunohistochemistry were used to measure the BMI-1 mRNA and protein levels in GIST tissues and normal tissues. Univariate survival analysis was used for determination of the factors that affect prognosis of GIST patients. Cox proportional hazards model was plotted to determine the independent risk factors for prognosis of GIST patients. RESULTS: The BMI-1 mRNA and protein levels in GIST tissues were higher than those in normal tissues. BMI-1 mRNA and positive protein levels were correlated with the National Institutes of Health (NIH) risk grade, tumor diameter and infiltration, and metastasis. There was a short survival period for the patients with a positive protein level and a high mRNA level of BMI-1. The site of primary tumor, tumor diameter, NIH risk grade, infiltration, and metastasis, as well as BMI-1 mRNA and protein levels were independent risk factors for prognosis of GIST patients. CONCLUSIONS: Taken together, these findings suggest there might be a relationship between BMI-1 mRNA and protein levels, and clinicopathological characteristics, including NIH risk grade, tumor size as well as infiltration and metastasis, of GIST patients. In addition, BMI-1 mRNA and protein levels were identified as independent risk factors for prognosis of GIST patients.