AsianScientist (Oct. 21, 2020) – Researchers in Japan have identified a marker that can track the response of patients with a particularly difficult-to-treat form of breast cancer known as triple negative breast cancer (TNBC). Their study published in Breast Cancer also suggests that the marker—a molecule called interleukin-34 (IL-34)—could be an attractive target for treating the disease.
Breast cancer is the most common cancer among women across the world, impacting 2.1 million women each year. The disease is classified into one of three types depending on the combination of cell receptor molecules present on the surface of the cancer cells: luminal A, Luminal B and HER2+. The receptors determine which hormone the cancer is dependent on for survival, and thus indicate which drugs can be used to treat the cancer.
However, there is a fourth type of breast cancer, triple negative breast cancer or TNBC, that does not have any of these three receptors. This type of cancer does not respond to standard treatments and the prognosis is generally poorer than for other types of breast cancer.
By analyzing data from over a thousand breast cancer patients from The Human Cancer Genome Atlas, a team of scientists from the Institute for Genetic Medicine (IGM) at Hokkaido University, Japan, found that TNBC is associated with high levels of a cytokine called IL-34. Because IL-34 is known to be associated with poor outcomes in lung cancer and liver cancer, the scientists decided to determine the relationship between IL-34 and TNBC.
To demonstrate that this relationship could be replicated in the lab, the scientists compared the growth and development of two cell lines that were identical except for the levels of IL-34 expressed: one cell line expressed high levels of IL-34 while the other expressed low levels. In cell culture, there was no difference observed between the cell lines; however, once introduced into mice, the cells that expressed high levels of IL-34 caused rapid tumor growth. Further research showed that IL-34 promotes creation of a favorable environment for the growth of tumors by protecting them from anti-tumor macrophages.
“Currently, chemotherapy is the only reliable means of treating TNBC, but it frequently develops resistance to chemotherapy,” said study leader Professor Ken-ichiro Seino. “Our findings show that IL-34 is an attractive molecular target for targeted cancer therapy.”
The article can be found at: Kajihara et al. (2020) Interleukin-34 Contributes to Poor Prognosis in Triple-Negative Breast Cancer.
Source: Hokkaido University; Photo: Shutterstock.
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