Source: Cancer  |  Posted 10 years ago

E-cadherin is under-expressed in primary tongue cancers, recurrences and nodal metastases. This under-expression seems to undermine prognosis.

Healthy epithelial cells express E-cadherin on their surface. However, in cancer, E-cadherin under-expression might facilitate metastasis.

To better characterise the role of E-cadherin in tongue cancer, researchers from the University of Hong Kong, Queen Mary Hospital, Hong Kong, examined its expression in 93 primary tongue carcinomas, seven locally recurrent tumours, and nine metastatic lymph nodes. The researchers also assessed methylation of the CpG islands in E-cadherin's promoter region in 70 primary tumours, seven locally recurrent tumours, and nine metastatic lymph nodes.

Eighty-three percent of primary tongue carcinomas under-expressed E-cadherin. Similarly, 86 and 89 percent of recurrent tumours and nodal metastases respectively under- expressed E-cadherin.

Sixty-four percent of primary tongue carcinomas showed hypermethylated E-cadherin. This compared to 71 and 67 percent of recurrent tumours and nodal metastases respectively.

E-cadherin under-expression was related to promoter hypermethylation. Indeed, primary and recurrent tumours as well as metastatic lymph nodes consistently showed weak E-cadherin expression because of promoter hypermethylation. Moreover, E-cadherin under-expression was associated with a poor prognosis in patients treated using primary surgery.

The authors concluded that methylation of CpG sites in the promoter region inhibits E-cadherin expression in primary oral tongue carcinomas, recurrences and nodal metastases. This down regulation is associated with a poor prognosis.