Epigenetic inactivation of the E-cadherin gene in eyelid sebaceous gland carcinoma

Background E-cadherin and beta-catenin are crucial components of the cell-cell adhesion complex. Their loss has often been associated with tumour metastasis and poor clinical outcome. Both loss of E-cadherin at the cell membrane and a stabilizing mutation in CTNNB1 (beta-catenin gene) have been associated with ovarian, colorectal, hepatocellular and nonmelanoma skin cancer, such as squamous and basal cell carcinomas. Absence of E-cadherin may be caused by promoter hypermethylation of the E-cadherin gene (CDH1). Objectives To determine the role of E-cadherin promoter hypermethylation and CTNNB1 gene mutation in the aggressive behaviour of sebaceous gland carcinoma of the eyelid. Methods Thirty-six cases of sebaceous gland carcinoma were subjected to E-cadherin methylation-specific polymerase chain reaction and mutational analysis for the CTNNB1 gene. E-cadherin and beta-catenin staining was evaluated by immunohistochemistry. Results were correlated with the clinicopathological features of sebaceous gland carcinoma. Results Methylation of the E-cadherin promoter region was detected in 72% of eyelid sebaceous gland carcinoma cases and loss of E-cadherin immunostaining in 83%. E-cadherin promoter hypermethylation showed a significant association with the loss of membranous E-cadherin (P = 0.038) and it was of borderline significance with reduced disease-free survival (P = 0.05). It was also found to be associated with advanced age (73%), tumour size >= 2 cm (77%), orbital invasion (83%), lymph node metastasis (60%), tumour recurrence (60%) and poor histological differentiation (90%). DNA sequencing revealed no stabilizing beta-catenin gene mutation in sebaceous gland carcinoma. Loss of membranous beta-catenin was observed in 61% cases, which associated significantly with both E-cadherin promoter methylation (P = 0.0262) and loss of E-cadherin membranous localization (P = 0.0015). Conclusion Epigenetic inactivation of the E-cadherin gene causes loss of membrane-bound E-cadherin and could contribute to the reduced disease-free survival in eyelid sebaceous gland carcinoma. Mutations in the beta-catenin gene do not seem to be involved in the pathogenesis of eyelid sebaceous gland carcinoma.