Expression Of Let-7d And Lin28in Acoustic Neuroma

background Acoustic neuroma is a benign tumor, which primarily comes from the Ⅷcranial nerve sheath, accounting for about90%of the cerebellopontine angle tumor, itsincidence rate show a up-tendency year by year. The traditional treatment includessurgical resection and stereotactic radiosurgery, however, these treatments bring aboutserious complications too. Therefore, it is of great significance to find a new method oftreatment of acoustic neuroma by the study of biological behaviour of acoustic neuromaand relavent genes about its occurrence and development. In recent years, in the area ofmolecular biology, the researchers found that the Let-7family acts as tumor suppressorgene in a variety of malignant tumor, at the same time, Lin28binding RNA protein actsas oncogene. What’s more, Lin28and Let-7could control each other, Lin28/Let-7axisconstitutes double negative feedback loop[1,2]. It is unclear that whether the Lin28/Let-7axis express, the expression level, the correlation of them and the role of them inacoustic neuroma cells. It is worthy of further study.objective To investigate the expression and relationship between microRNA Let-7d andRNA binding protein Lin28A/Lin28B in acoustic neuroma tissues; and to speculate thepotential clinical significance and effects on tumor progression.methods18cases of acoustic neuroma tissues were obtained as experimental group, and7cases of normal vagus nerve tissues were selected as control group. The expression ofLet-7d and Lin28A/Lin28B was detected by means of real time polymerase chainreaction. Data was analyzed by2–ΔΔCTmethod, and then results statistical analysis wasperformed by Mann-Whitney test. The relativity between the expression of Let-7d andLin28A/Lin28B in acoustic neuroma tissues was analyzed. Immunohistochemicalmethod was used to detect the differential expression of Lin28protein between the twogroups.Results Compared to the control samples, real-time quantitative PCR results showed that Let-7d expressed significantly enhanced in acoustic neuroma tissues (P <0.001);whereas Lin28A and Lin28B were expressed significantly reduced(PLin28A=0.004,PLin28B=0.001). Between acoustic neuroma and normal vagus nervetissues, the correlation coefficient of Let-7d and Lin28A is r=0.767, P <0.001, and thatof Let-7d and Lin28B is r=0.812, P <0.001. Let-7d levels was negatively correlatedwith Lin28A and Lin28B in both acoustic neuroma and normal vagus nerve tissues. It isshowed by immunohistochemistry that no positive staining of Lin28protein was foundin both two groups.Conclusion The expression of Let-7d increases and the expression of Lin28A/Lin28Bdecreases, which may play an important role in the growth and the procedure ofmalignant transformation in acoustic neuroma.