When cancer spreads to the bones and bone marrow, treatment becomes difficult and the survival rate of patients sharply declines. About 70% of patients with breast cancer and prostate cancer die due to bone metastasis. Scientists have for the first time revealed how cancer cells survive in oxygen-deprived bones, which is expected to greatly aid cancer treatment.
Yibin Kang, a professor of molecular biology at Princeton University, noted on the 3rd (local time), "We have discovered for the first time that cancer cells take iron from immune cells to produce hemoglobin and thrive in the hypoxic environment of the bones." The research findings were published that day in the international journal Cell.
To understand how cancer cells adapt in the bones, the research team observed bone marrow where cancer cells were grown. By labeling the cells and decoding the genes at the single-cell level, they confirmed that immune cells known as macrophages gathered around the cancer cells.
Macrophages originally supply iron to aid red blood cell growth. However, when iron is taken by cancer cells, they inadvertently assist the cancer cells. It is like a soldier's supplies being taken by the enemy, thereby helping them. The research team also revealed that this process interferes with the final stage of red blood cell maturation, known as nuclear expulsion. If red blood cells remain immature, they worsen anemia due to iron deficiency in the bone marrow. This explains why patients with cancer that has metastasized to the bones experience anemia.
Cancer cells synthesize hemoglobin to supply oxygen from the iron they have taken from macrophages. Thanks to this, they can survive and grow even in the oxygen-deprived environment of the bones. Cancer cells have created an impregnable fortress in difficult terrain with supplies taken from the enemy.
Professor Kang stated, "Cancer cells behave like red blood cells and create an environment advantageous for their survival," adding, "This discovery will be an important clue for understanding and developing treatment strategies for bone metastasis." The research team studied metastatic breast cancer this time, but they believe the findings may also apply to major other cancer types. They indicated that they will look for ways to slow or treat bone metastasis while also alleviating anemia, a common complication of cancer.
References
Cell(2025), DOI: www.doi.org/10.1016/j.cell.2025.08.013