Overexpression of certain oncogenes in MCF10A, including ErbB2/HER2, leads to increased proliferation and deficient luminal apoptosis in 3D Matrigel, resulting in enlarged structures with filled lumens, resembling phenotypes found in early stages of breast cancer, such as atypical hyperplasia and DCIS [26]–[28]. The gene discussed is ERBB2; the disease is ductal breast carcinoma in situ.