The Expression Of CXCL12 And CXCR4 In Salivary Adenoid Cystic Carcinoma And The Peripheral Nerve Tissue

Objective:To observe the expression of the chemokine CXCL12 in human peripheral nerve tissue and the expression of the chemokine receptor CXCR4 in the primary lesions of salivary adenoid cystic carcinoma . In order to study the relationship between the biological axis of CXCL12/CXCR4 and the neural invasion of salivary adenoid cystic carcinoma.Methods: There were three sections in this experiment:1. To cut 15 pieces serial sections at 4μm intervals from the 41 cases of salivary adenoid cystic carcinoma and the 30 cases of tongue cancer,then put them into five groups,each three successive sections were put into the same group .we have taken one section from each group (five sections per case )to stain with hematoxylin and eosin,then to observe the histopathological appearance of salivary adenoid cystic carcinoma and the tongue cancer, and to select the cases containing the nerve tissue, then to compare the rate of the neural invasion between ACC and tongue cancer.2. To select one section at random from successive pieces of 41 specimens of ACC cases and 30 specimens of tongue cancer cases,and select 20 cases of mixed tumor of parotid gland as innocence control. Using the Envision method to detect the expression of the chemokine receptor CXCR4 in paraffin sections of salivary adenoid cystic carcinoma,tongue cancer and mixed tumor of parotid gland. Then to compare the different expression of CXCR4 among the three kinds of tumors using statistical method(chisquare test).3. To select the ACC and tongue cancer specimens containing the nerve tissue from the cases of the experiment of part one, then to choose one section from successive pieces of these specimens,and choose 20 specimens of normal nerve tissue taken from the surgical specimens of head and neck far away from the primary lesions as innocence control. Using the Envision method to detect the expression of the chemokine CXCL12 in paraffin sections of salivary adenoid cystic carcinoma,tongue cancer and normal nerve tissue.Then to compare the different expression of the chemokine CXCL12 adopting statistical method(chisquare test),in order to analyze if there is significant difference on the expression of CXCL12 existing in the peripheral nervus of the two kinds of tumors and the normal nerve tissue . All the data of the experiment was analyzed by the SPSS 11.0 statistical software ,chisquare test.Results:1. Under the light microscope we found that among all the 41 cases of the ACC there were 32 cases containing nerve tissue , in which 19 cases had the histopathological appearance of neural invasion, and 5 cases had clinical symptoms of neural invasion via reviewing the case history , among which there were 3 cases had both the clinical symptoms and the histopathological appearance. On the other hand in the 30 cases of tongue cancer there were 21 cases containing nerve tissue ,of which there were 4 cases appearing the neural invasion. By comparison, we found that the neural invasion rate of ACC(65.63%)was much higher than that of tongue cancer (19.05%), x~2=11.04, P<0.01, there was significant difference between them.2. We detected that the chemokine receptor CXCR4 was expressed in ACC cells,tongue cancer cells,mixed tumor cells through immunohistochemical assessment. In these cells, CXCR4 expression mainly located in the cytoplasm, and some in nuclei. The positive rate of ACC 63.41% was much higher than that of tongue cancer group 36.67% (x~2 =4.97,P<0.05); and also much higher than that of mixed tumor group 35%(x~2 =4.37,P<0.05).There was no significant difference(P>0.05)on the positive rate between tongue cancer and mixed tumor.3. By immunohistochemistry detection, we found that the chemokine CXCL12 was obviously expressed in the nerve tissue of SACC,tongue cancer as well as in the normal nerve tissue. The expression mainly located in the cytoplasm of cells, and some in the nuclei. By statistics,we found the positive rate of nerve tissue in SACC was 59.38%,61.90% in tongue cancer and 75% in normal nerve tissue. By the chisquare test we drew the conclusion:P>0.05,consequently there was no significant statistical difference among them.Conclusions:1. Through the pathological observations of the nerve tissue in the different tumors,the rate of neural invasion in SACC was higher than that in tongue cancer. This finding showed that tendency of SACC attacking the nerve tissue was much more than that of the tongue cancer. The result was consistent with the actual character.2. Among the SACC,tongue cancer and mixed tumor,the expression of CXCR4 in the SACC was significantly higher than that of the others, and there was no significant difference on the expression of CXCR4 between the tongue cancer and the mixed tumor.3. There was high expression of chemokine CXCL12 in the human peripheral nerve tissue ,and the different kinds of tumor cells had no obvious effects on the levels of CXCL12 in nerve tissue. We presumed that CXCL12 might be secreted from nerve tissue itself.4.The biological axis of CXCL12/CXCR4 may be material foundation on which SACC cell attacked nerve tissue and diffused along nerve tissue specifically in earlier period.