Breast Cancer Sleeper Cells

Seventy percent of all breast cancers are estrogen-receptor positive, and hormone therapies are used to treat this type of breast cancer. A course of hormone therapy (either tamoxifen or aromatase inhibitors) targeting estrogen receptors are given after first removing the tumor with surgery. But, about 30 percent of patients taking hormone therapies find their cancer ultimately return, and in some cases, as long as 20 years after treatment. In addition, the returning cancer is often found to be metastatic, that is, it has spread around the body, and even worse, the tumors are likely to be resistant to medication.
Findings from a recent study by scientists of Imperial College London suggest that breast cancer medicines may, in fact, compel some cancer cells into ‘sleeper mode’, potentially allowing them to return many years after treatment. Lead author Dr. Luca Magnani stated, “For a long time scientists have debated whether hormone therapies, which are a very effective treatment and save millions of lives, work by killing breast cancer cells or whether the drugs flip them into a dormant ‘sleeper’ state. This is an important question as hormone treatments are used on the majority of breast cancers.” He further added, “If we can unlock the secrets of these dormant cells, we may be able to find a way of preventing cancer coming back, either by holding the cells in permanent sleep mode, or be waking them up and killing them.”
Previous work by the same team suggested that cells can make their own ‘fuel’, thus avoiding being ‘starved’ by treatment. Study co-author Dr. Sung Pil Hong said, “Our experiments suggest these sleeper cells are more likely to travel around the body. They could then ‘awaken’ once in other organs of the body, and cause secondary cancers. However, we still don’t know how these cells switch themselves into sleep mode, and what would cause them to wake up. These are questions that need to be addressed with further research.”
Reference: Nature Communications, volume 10, article number 3840 (2019), https:urlzs.com/kEtCD