Differences and Molecular Immunohistochemical Parameters in the Subtypes of Infiltrating Ductal Breast Cancer

Breast cancer is a heterogeneous disease, and patients are categorized into subtypes according to gene expression. We studied the associations among molecular, immunohistochemical, and clinicopathologic features and their distribution according to the subtypes luminal, HER2, basal, and normal-like in 60 patients with invasive ductal breast carcinoma without distant metastasis at the time of diagnosis (M0). We evaluated the hypermethylation of the CDH-1, RASSF1A, SIAH-1 and TSLC-1 genes by methylation-specific polymerase chain reaction and the expression of p53, bcl-2, cyclin D1, E-cadherin, and β-catenin proteins in tissue microarrays by immunohistochemical analysis. Expression of bcl-2 was associated with the luminal subtype (P = .003), and CDH-1 hypermethylation was present preferentially in HER2 tumors (P = .038). The basal subtype was characterized by the expression of β-catenin (P = .003). The hypermethylation of CDH-1 and the expression of bcl-2, cyclin D1, and β-catenin proteins differ among breast cancer subtypes.