The Study Of The MYB Gene Translocation And Expression In Adenoid Cystic Carcinomas

PURPOSES: To analyze the clinicopathological characteristics and prognostic factors of salivary adenoid cystic carcinoma(SACC)and primary intraosseous adenoid cystic carcinoma(PIACC)in Chinese population and investigate the correlation between the MYB gene rearrangement,expression and clinicopathological features of SACC and prognosis of patient.METHODS: The clinical data of 97 cases of SACC and 4 cases of PIACC in our hospital were retrospectively analyzed,and the clinical pathological data were collected and followed up in.Immunohistochemistry(IHC)to detect the expression of MYB protein;reverse transcription PCR(RT-PCR)for detection of MYB-NFIB fusion gene;quantitative real-time PCR(q RT-PCR)to detect the expression of MYB m RNA;lentiviral transfection of MYB-NFIB fusion gene sequence into SACC-83 cells;fluorescence in situ hybridization(FISH)detect the changes of MYB gene.All data were evaluated by SPSS.RESULTS:1.Male to female ratio was 1.16:1,the average age was 53.9 years old,distant metastasis rate was 56.4%,local recurrence rate was 33%.The risk of local recurrence was higher in male patients,minor salivary gland origin,advanced stage of TNM,high histological grade,positive margin,and the factors affecting metastasis included advanced stage of TNM and high histological grade.2.The positive rate of MYB protein reached 69.1%.MYB protein expression was much lower in solid type than cribriform and tubular types.The expression of MYB in normal glands was negative while the other salivary gland tumors can be positive.3.The positive rate of MYB-NFIB fusion gene in 97 cases of SACC was 71.1%.The MYB-NFIB fusion gene was not detected in normal gland,malignant pleomorphic adenoma,SACC-83/LM cell lines.The expression of MYB 3 ’end of m RNA gene in fusion negative cases was higher than that of fusion positive,and the expression of 5’ was not significantly different.The introduction of MYB-NFIB fusion gene into SACC-83 can lead to the up regulation of MYB expression.Compared with the control group,the malignant biological behavior of SACC-83 cells transfected with fusion gene was decreased.4.FISH detection showed that MYB gene alteration has been found in 83 out of the 97 SACC cases.MYB gene has no change in normal glands and other salivary glands tumors.Occurrence rate of MYB rearrangement was much higher in TNM III/IV than I/II patients(p=0.033).Survival analysis showed prognosis is much better in MYB gene normal group than MYB rearrangement group.5.4 cases of PIACC showed high levels of MYB protein expression and abnormal MYB gene.CONCLUSIONS: Local recurrence and distant metastasis rate of SACC is high and is the main cause of death.The specificity of MYB gene rearrangement was higher than that of MYB protein expression.There was no significant correlation between MYB gene rearrangement and protein expression.In addition,the negative MYB gene changes in SACC patients detected by FISH with a better prognosis.The PIACC and SACC have the same origin.