Despite many awareness campaigns and scientific research, breast cancer remains the second most common cause of death in women after lung cancer.
What is Metastasis?
The researchers discovered that one protein that was once inactivated could prevent the spread of aggressive breast cancer to other parts of the body, a process known as metastasis.
Deaths due to breast cancer occur due to metastases or the spread of breast cancer from the original site of the tumor to the rest of the body.
It is estimated that between 6% and 10% of new breast cancer cases are already metastatic at the time of initial diagnosis.
New research brings us closer to understanding metastases and what we can do to stop them.
Dr. Ainhoa Mielgo, of the Department of Cancer Studies at the University of Liverpool in the United Kingdom, led the new study, and the first author of the article is Lucy Ireland, Ph.D. Candidate in Dr. Ing. Mielgo’s group.
“Understanding the mechanisms underlying the metastatic spread of breast cancer is essential to improve patient care and outcomes,” says Dr. Mielgo.
Protein AXL
In the study, published in the journal Cell Reports, researchers have shown that one protein, AXL, affects the onset of metastases in HER2-positive cancer, an aggressive type responsible for 20% of breast cancers.
In HER2-positive breast cancers, cells with high levels of AXL are more likely to secrete tumors to form metastases.
The research was conducted in mice and with tumor cell samples from cancer patients in Montreal, Canada.
Women with HER2-positive cancer have been found to have less AXL, the better the survival rate.
Previously, researchers had linked the AXL protein to another type of cancer, triple negative breast cancer, but its role in HER2-positive cancer was unknown.
“Based on this discovery, treatment targeting AXL may reduce the risk of metastasis,” said Jean-Francois Cote, a professor at the University of Montreal in Canada.
What is IGF?
IGFs are hormones that stimulate growth. Of course, IGF-1 and IGF-2 are present in our blood, but the new study found that breast cancer tumors also express IGF-1 and -2, helping them grow.
Discovery of hormone that drives tumor progression
To achieve this, Dr. Mielgo and his team analyzed how a class of immune cells affecting macrophages, the spread of breast cancer.
As the authors explain, macrophages are abundant in the microenvironment of tumors, and these cells can stop or promote the spread of breast cancer. The researchers then performed a series of experiments on cell lines to investigate exactly how these cells facilitate the spread of cancer.
In their study, scientists have been guided by earlier research that has shown that macrophages express high levels of so-called insulin-like growth factors (IGFs) in certain cancers.
In particular, it has been discovered that macrophages express high levels of these hormones, causing the spread of cancer in the lungs.
In addition, Dr. Mielgo and her team of breast cancer patients found that IGF receptors were very active in 75% of cases and that this percentage was proportional to macrophage infiltration and the progression of the tumor.
In addition, “in patients with invasive breast cancer, insulin / IGF-1 receptor activation increased to 87 percent,” the authors write.
An experiment that may stop metastasis
Importantly, the team blocked the mouse IGF levels and combined this intervention with paclitaxel, a chemotherapy commonly used in the more aggressive forms of breast cancer.
The combination of this result and use of paclitaxel alone led to “a significant reduction in tumor cell proliferation and lung metastasis”.
Dr. Mielgo explains: “These results justify the further development of the combination of paclitaxel with IGF inhibitors for the treatment of invasive breast cancer.”
