Expression and significance of differentiation inhibitor 1, 3 and matrix metalloproteinase-9 in brain metastatic tumors

Abstract

Objective To observe the expression of differentiation inhibitor 1 (Id-1),Id-3 and matrix metalloproteinase-9 (MMP-9) in cerebral metastatic tumors and to explore their roles and mechanism in the formation and development of cerebral metastases.Methods The expression of Id-1,Id-3 and MMP-9 mRNA and protein in cerebral metastases was detected by using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry.The correlation of their expression was assayed statistically.Results The relative expression levels of Id-1,Id-3 and MMP-9 mRNA were 0.75 ± 0.07,0.83 ± 0.06 and 0.72 ± 0.09 respectively in brain metastases,obviously higher than those in human normal brain tissues (P ＜0.05).The positive expression rate of Id-l,Id-3 and MMP-9 protein was 92.3％,94.9％ and 79.5％ respectively in brain metastases,obviously higher than those in in human normal brain tissues (P ＜ 0.05).The expression of Id-1,Id-3 mRNA and protein had a positive correlation with that of MMP-9 in metastases (r =0.569,P ＜ 0.01 ; r =0.386,P ＜ 0.05).Conclusion The over-expression of Id-1,Id-3 and MMP-9 played an important biological function in the formation of brain metastatic tumor,and there was a synergistic effect among them to some extent. Key words: Differentiation inhibitor 1,3; Matrix metalloproteinase-9; Brain metastatic tumors