Scientists, based at the Queen Mary University of London, have discovered a new mechanism that signals which Ductal Carcinoma in Situ (DCIS) tumours may progress to invasive breast cancer. This might help avoid unnecessary treatment for some women with DCIS in the future.

Scientist working in the tissue bank

Researchers, using samples from our Tissue Bank, have furthered our understanding of ductal carcinoma in situ (DCIS), an early form of breast cancer.

They found that physical changes in cells in the breast duct, called myoepithelial cells, play an important role in DCIS progressing to invasive breast cancer.

The researchers hope that in the future, these findings could help predict which DCIS tumours go on to become invasive breast cancer.

Understanding DCIS

DCIS is an early form of breast cancer. The breast cancer cells remain in the breast ducts and can't spread into surrounding tissue. In some cases, DCIS will never develop further or grows so slowly that it would never cause harm during a person’s lifetime. In other cases, it will progress to become invasive breast cancer.

However, currently we don’t know how to tell apart DCIS cases that will become invasive breast cancer and those that won’t. And because of that most people with DCIS will receive treatment, which can come with unpleasant side effects.

That’s why researchers based at Queen Mary University of London, wanted to better understand how DCIS breaks out of the breast duct into the rest of the breast. And, figure out if they could predict which DCIS cases are more likely to become invasive. 

Breaking through the barrier

The researchers focused on a specific type of cell in the breast ducts. These cells, called myoepithelial cells, live in the breast duct. They can act as a sheet around the DCIS tumour, and separate the cancerous cells from the rest of the breast.

Normally, these cells form a barrier that can help prevent cancer from growing larger and spreading to the rest of the breast. However, research has shown that in some DCIS tumours, these myoepithelial cells look and act differently. And, scientists suspect they might help the tumour cells instead of stopping them.

Stretching the myoepithelial cells

Using samples from our tissue bank, the researchers found physical changes caused by a DCIS tumour stretching these cells can trigger mechanisms in these cells that can help the disease become invasive.

They found that when the myoepithelial cells were stretched in the lab, they started to look like myoepithelial cells associated with invasive DCIS. They also found that stretching these cells caused them to make a proteins called MMP9 and MMP13, which can help DCIS progress to invasive breast cancer. 

In the future, researchers hope these findings could help predict which DCIS cases are a at a higher risk of becoming invasive breast cancer. They also hope that by uncovering the role myoepithelial cells play in DCIS becoming invasive, these cells could potentially be a target for new drugs aiming to stop DCIS progressing.

Dr Kotryna Temcinaite, senior research communications manager at Breast Cancer Now, added: ‘This information helps us provide a better understanding of how DCIS works and could help women avoid unnecessary treatments in the future. We welcome studies that will build upon this research to find new ways in which we can identify women who would benefit from having their DCIS treated and those who wouldn't.’

The study was published in the journal Nature and used breast tissues provided by our Tissue Bank

Discoveries like this are an important step towards the best possible treatments and support for people affected by breast cancer.

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