Scientists shed new light on how early-stage breast cancer spreads to other organs

A consultant analyzes a mammogram.

Rui Vieira | PA wire | Getty Images

Scientists have shed new light on how early-stage breast cancer spreads to other organs undetected, which can cause fatal metastatic cancer in some women years later.

Even before a breast cancer tumor is detected, cells that are not yet malignant can spread to other organs where they are dormant and not replicating, according to new research led by Professor Maria Soledad Sosa. at the Tisch Cancer Institute at Mount Sinai in New York.

The NR2F1 gene normally prevents premalignant cells from spreading to other parts of the body.

Sosa and a team of scientists discovered that a cancer gene, HER2, suppresses the NR2F1 gene, allowing pre-cancerous cells to move to other organs in the body where they can become cancerous.

“Evidence suggests that even before a primary tumor is detectable, you may have cells that also spread to secondary organs and they may eventually metastasize as well,” Sosa said. The lungs, bones and brain are places where breast cancer can metastasize or spread.

The team’s research was published Tuesday in the peer-reviewed journal Cancer Research. The lab study was conducted using samples from an early form of breast cancer known as ductal carcinoma in situ, or DCIS, as well as cancerous lesions from mice.

Sosa, the study’s lead author, said understanding the mechanism that allows pre-malignant cells to spread throughout the body could one day help determine which women are at higher risk for breast cancer recurrence. breast. If a patient has low levels of NR2F1, it could be a sign that dormant cancer cells are spreading through the body where they can later reactivate and cause disease.

The results of the study could impact how women diagnosed with DCIS are treated. DCIS is an abnormal cell growth in the lining of the milk duct of the breast that has not developed into a malignant tumor. DCIS is traditionally considered non-invasive, meaning the abnormal cells have not yet spread. However, research by Sosa’s team and others challenges this notion.

More than 51,000 women in the United States will be diagnosed with DCIS this year, according to the American Cancer Society. Many women diagnosed with DCIS undergo either surgery, radiation therapy, or both. However, women diagnosed with DCIS who undergo these treatments still have about a 3% chance of dying from breast cancer 20 years after their diagnosis, according to a pioneering study published in Jama Oncology in 2015.

More than 150 women in the study who had their breasts removed still died of cancer, meaning the disease had likely spread at the time of detection. The scientists concluded that the classification of DCIS as non-invasive should be reconsidered, warning that some cases of carcinoma have an inherent potential for distant spread to other parts of the body.

“Even if they do the DCIS surgery or sometimes it’s treated with radiation therapy, the mortality rate doesn’t change. That tells you that it doesn’t matter what’s in your primary site,” Sosa said. The problem is that the abnormal cells spread from the carcinoma, she said.

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