How Myoepithelial Cells Actively Stop Situ Breast Cancer from Becoming Invasive

Situ breast cancer is a form of breast cancer that is non-invasive. Also known as ductal carcinoma in situ, this is where the cancer cells lining the milk ducts have not metastasized to the surrounding breast tissue. In infiltrating breast cancer, the cancer cells have already progressed beyond the ducts through the lymphatic and blood systems to the other body parts.

The myoepithelial layer assists physicians to determine whether the cancer is invasive or non-invasive. Once the cancer cells have broken through the myoepithelial layer, the diagnosis is positive for invasive breast cancer, which is very difficult to treat.

A new research reveals that myoepithelial cells are an active barrier against breast cancer cells. The myoepithelium actively seizes the cancer cells that try to escape to the other parts of the body.

During the study:

Researchers collected breast duct cells from mice and used them to produced Twist1 protein, which was previously associated with metastasis of cancer.

On examining the behavior of the Twist1 cells under the microscope, it was discovered that the myoepithelium seized the invasive cells and yanked them back into the milk duct. All the 114 observations resulted in 92% accuracy.

To confirm this finding further, the researchers changed the ability of the myoepithelial cells to contract and the ratio of myoepithelial cells to the invasive cancer cells. They closely monitored the effect of the changes on the number of cancer cells that broke away and compared with them with the normal myoepithelium.

When the cells were engineered to be less contractile, the number of cells that broke through the myoepithelium was three times the number of cells that escaped via the normal wall of the myoepithelium.

Whenever two myoepithelial cells were added to each invasive cancer cell, the number of cancer cells that escaped via the myoepithelium reduced by four times compared with not having any myoepithelium.

These findings helped researchers to have a deeper understanding on the way cancer cells are contained. This would go a long way in helping physicians develop ways of predicting a patient’s risk of metastasis. The findings suggest that the physical completeness of the myoepithelium and the gene expression with thin the myoepithelial cells are significant in foretelling the behavior of breast tumors in patients. They also establish the fact that myoepithelium is not just a stone wall, but a dynamic barrier to cell escape.

Comments