Differential expression of insulin-like growth factor binding protein- 3 in the different grades of glioma and its correlation with malignancy of glial tumors

Objective To explore the differential expression of insulin- like growth factor- binding protein- 3(IGFBP- 3)in normal brain tissue and different grades of gliomas,and its corralation with the differentiation and malignance of gliomas. Methods By real- time quantitative polymerase chain reaction (Real- time PCR)and immunohistochemical staining methods, the expression of IGFBP- 3 was detected in 11 cases of grade-Ⅱglioma tissue samples, 14 cases of grade-Ⅲglioma tissue specimens, 9 cases of grade-Ⅳgrade glioma tissue samples,and 16 specimens of normal brain tissue. Results The average optical density values of IGFBP- 3 in normal brain tissue specimens and the specimens of grade-Ⅱ,-Ⅲ,-Ⅳgliomas were 1.082 2±0.334 7, 1.535 0±0.226 7, 4.383 1±0.521 8, and 5.094 1±0.652 5 respectively.Single factor analysis of variance(One- way ANOVA)and LSD, SNK- t analysis comparison showed there was significant difference in the expression of IGFBP- 3 between human gliomas and normal brain tissue(P< 0.05), and between grade-Ⅱand grade-Ⅲor grade-Ⅳgliomas(P< 0.05).By immunohistochemical staining methods,the positive expression rate of IGFBP- 3 was 20.0% in normal brain tissue specimens, which was significantly lower than in grade-Ⅱ(33.3%),-Ⅲ(57.1%), and-Ⅳ(80.0%)glimas(P<0.05 for all).There was no significant difference among different grades of gliomas. Conclusion The expression of IGFBP- 3 was significantly reduced in gliomas,and closely related with disease progression. Key words: Glioma; Insulin- like growth factor binding protein- 3; Promote apoptosis