The aim of our study was to determine and compare the immunohistochemical (IHC) expression of Sdc1 in the malignant epithelial cells and tumor stroma of the two, by far, most common histological types of breast cancer, invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC), and in the axillary lymph node metastases of ductal type. Here, SDC1 is linked to neoplasm.