Expressions And Significance Of BDNF And TrkB In Salivary Adenoid Cystic Carcinoma

Purpose: Adenoid cystic carcinoma (ACC) is a common salivary gland malignancy which accounted for 24% and threatens the patients's lives. It had a close relationship with multitude oncogene and suppressor gene. Brain-derived neurotrophic factor(BDNF) is a member of a family of neurotrophins, BDNF gene located on the short arm of chromosome 11 at position 11p13, Tyrosine kinase B (TrkB) is one of the family of Trks, TrkB gene is located on the long arm of chromosome 9 at position 9q22. We used immunohistochemical SP techniques to detect the expression of BDNF and TrkB in SACC and explore its relationship with the clini-pathological features and biological behavior of SACC.Materials and Methods:1. 12 normal salivary gland (NSG) and 45 salivary adenoid cystic carcinoma (SACC) were selected. Clinical information was collected including patient age, sex, location pathological type, perineural invasion, lymph node metastasis and clinical stage.2. Using immuohistochemical SP staining, we examined protein BDNF and TrkB expression in paraffin slices of 45 salivary adenoid cystic carcinoma. As control, expression of these proteins in 12 normal salivary gland were also detected.3. Difference of BDNF and TrkB were analyzed in normal gland and salivary adenoid cystic carcinoma, Relationships of these proteins expression with clini-pathological parameter were analyzed in SACC, and so were relationship of BDNF expression with TrkB expression. Result:1. The expression of BDNF in SACC cells major located in cytoplasm, and a few expression located cellular nucleus. The expression of TrkB in SACC cells major located in cytoplasm and cellular nucleus.2. The positive expression rate of BDNF is 84.4%(38/45)in SACC, but 50%(6/12) positive expression in NSG.. The positive expression rates of BDNF has statistical significance between the SACC and NSG(P<0.05). The positive expression rate of TrkB is 88.9%(40/45)in SACC, whereas 41.7% in NSG.. The positive expression rates of TrkB has statistical significance between the SACC and NSG(P<0.05).3. In SACC, expression of BDNF had no correlation with histological tape and perineural invasion(P>0.05),But it had correlation with lymph node metastasis and clinical stage(P<0.05). Expression of TrkB had correlation with clinical stage, perineural invasion and lymph node metastasis(P<0.05).4. 35 cancers of TrkB were positive expression in 38 cancers of BDNF positive expression while 2 cancers of BDNF negative expression in 5 cancers of TrkB negative expression. Inverse relationship between BDNF and TrkB expression was observed in SACC(r=0.719,P<0.05).Conclusion :TrkB and BDNF played an important role in the development and progression of SACC, TrkB played an important part in perineural invasion of SACC, Expression of BDNF and TrkB were significantly associated with tumor metastasis in SACC, which were valuable markers predicting biological behavior and trend of metastasis of SACC.