Breast cancer medicines may force some cancer cells into “sleeper mode,” allowing them to potentially come back to life years after initial treatment, according to the early-stage findings from scientists at Imperial College London.
The new research has found the entrance of the way of keeping the cancer cells dormant for longer, or even awakening the cells so they can then be killed by the treatment.
Kill cancer cells or switch them into sleep modes
Hormone therapies are commonly used in breast cancer patients, saving millions of lives around the world. But debates have existed whether the treatment kills the cancer cells, or only switches them into sleep modes.
The study found that the treatment can kill some of the cells while switch others into the sleeper state. Scientists are finding ways to unlock the secrets of the dormant cells, so that ways of preventing cancer coming back may be discovered.
About the research
Researchers studies around 50,000 human breast cancer single cells in the lab, and found that hormone treatment can leave a small proportion of the cancer cells as being in a dormant state.
The dormant cells may also help explain why some breast cancer cells become resistant to treatment, causing a patient’s drugs to stop working, and their cancer to return.
Hormone therapy is usually applied to patients with a type of breast cancer called oestrogen-receptor positive, after the tumor is removed with a surgery. About 70% of breast cancer patients have this type of breast cancer and receive hormone treatment.
However, about 30% of breast cancer patients have the cancer return, sometimes as long as 20 years after treatment. The returning cancer usually spreads around the body (called metastatic), and tumors are often now resistant to medication.
The new study shows that the sleeper cells seem to be an intermediate stage to the cells becoming resistant to the cancer drugs, and are actually triggered by the drugs to enter the sleeper state.
Dr. Rachel Shaw from Cancer Research UK said: "Although treatments for breast cancer are usually successful, cancer returns for some women, often bringing with it a poorer prognosis. Figuring out why breast cancer sometimes comes back is essential to help us develop better treatments and prevent this from happening. This study highlights a key route researchers can now explore to tackle 'sleeping' cancer cells that can wake up years after treatment, which could potentially save the lives of many more women with the disease."