CDH1 methylation analysis in invasive lobular breast carcinomas with and without gene mutation

Abstract The proposed role of CDH1 (E-cadherin gene) methylation as a mechanism of gene inactivation in Invasive Lobular Carcinoma (ILC) remains inconclusive. Using pyrosequencing, we analyzed CDH1 hypermethylation in E-cadherin deficient ILC cases with varied CDH1mutation status and Invasive Breast Carcinomas Non-Special Type (IBC-NSTs), finding no hypermethylation in any group of ILCs. In addition, CDH1 methylation correlated with the presence of Tumor-Infiltrating Lymphocytes (TILs). These findings challenge CDH1 methylation as a CDH1 inactivation mechanism in ILC and highlight TILs as a potential confounding factor in the gene methylation.