[Expression and significance of E-cadherin in adenoid cystic carcinoma of salivary glands].

Objective: To examine the expression of E-cadherin and the methylation status of CDH1 and explore their clinical significance in salivary adenoid cystic carcinoma (SACC).

Methods: The expression of E-cadherin was detected by the immunohistochemical method. And the methylation of CDH1 gene promoter 5'-CpG island was analyzed by real-time methylation-specific polymerase chain reaction (real-time MSP) in salivary adenoid cystic carcinoma and normal salivary gland tissue respectively.

Results: The expression rate of E-cadherin was lower in SACC than that in normal salivary gland tissue (100.0% vs 55.6%, P < 0.05). And the expression of E-cadherin was associated with different histopathological types, T-stage, nerve invasion, lymphatic and distant metastasis (P < 0.05). However, there was no correlation between the expression of E-cadherin and gender, age and tumor location. Partial methylation of CDH1 was detected in 3 of 30 cases with a positive expression of E-cadherin and full methylation of CDH1 in 23 of 24 cases with a negative expression of E-cadherin. There was a negative correlation between the expression of E-cadherin and the methylation of CDH1 in salivary adenoid cystic carcinoma (r = -0.483, P < 0.001).

Conclusion: The down-regulation of E-cadherin, as modulated by the methylation of CDH1, may contribute to nerve invasion, lymphatic and distant metastasis in SACC. Thus it may be used as a biological indicator of malignancy and prognosis.