Hormone Therapy for Breast Cancer May Result in “Sleeper Cells” That Later Awaken

According to a study published in Nature Communications, adjuvant endocrine therapy for breast cancer may only force some cancer cells into “sleeper mode,” which may come back years after initial treatment.

“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,” said lead author Luca Magnani, PhD, principal research fellow in the faculty of medicine at Imperial College London in the United Kingdom, in a press release. “This is an important question as hormone treatments are used on the majority of breast cancers. Our findings suggest the drugs may actually kill some cells and switch others into this sleeper state. 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.”

Awakening cells can result in secondary cancer

Researchers assessed nearly 50,000 human breast cancer single cells in the laboratory and found that treatment with hormone treatment exposed a small proportion of these cells as being in a dormant state. They also noted that cells in this dormant sleeper state are more likely to spread throughout the body and could “awaken” up to 20 years later and result in secondary cancers.

However, the researchers noted that hormone therapy remains one of the most effective treatments for breast cancer and further research is necessary.