Scientists at Weizmann Institute of Science in Israel have found that a hormone that keeps humans awake during the day is also responsible for suppressing the growth of cancer cells.
The finding suggests that night is the appropriate time for deadly cancer to quickly grow and spread in the body. Administering certain treatments in accordance with the body's day-night cycle may enhance their efficiency.
As a result, doctors could administer certain anti-cancer drugs at night to inhibit the growth.
"It seems to be an issue of timing," Prof. Yosef Yarden of the Weizmann Institute's Biological Regulation Department, said in a statement. "Cancer treatments are often administered in the daytime, just when the patient's body is suppressing the spread of the cancer on its own. What we propose is not a new treatment, but rather a new treatment schedule for some of the current drugs."
For the study, the researchers injected Lapatinib - one of the new generation of cancer drugs - to mouse models of cancer at different times of day. This breast cancer drug is designed to hinder the epidermal growth factor receptor EGFR and to prevent the growth and migration of the cancer cells.
The researchers found significant differences between the sizes of tumors in different groups of mice, depending on the administration time of the drug. This EGFR receptor is more active during sleep and calm during waking hours. They said that higher levels of the glucocorticoid (GC) steroids hinder the growth of cancer, whereas lower levels enable its growth.
The finding is published in the journal Nature Communications.
