Tight Junctions: A Barrier to the Initiation and Progression of Breast Cancer?

Figure 2

The potential influence of TJ proteins on breast cancer development. Breast cancer predominantly begins in luminal epithelial cells lining the normal breast ducts (a). Alterations in TJ proteins may lead to the initiation of breast tumourigenesis in at least two ways. Firstly, TJ alterations may favour decreased cellular apoptosis and increased proliferation leading to uncontrolled growth, such as is seen in ductal carcinoma in situ lesions (b). Secondly, TJ alterations may decrease cell adhesion and increase motility, facilitating cancer cell migration as seen during invasion and basement membrane breakdown in early primary invasive breast carcinoma (c). Breast carcinoma likely requires coordinated efforts of both increased proliferation and increased motility to progress to metastatic stages (d).