Like some bacteria, fungi, and mold that grow and spread in dark, damp places, tumors tend to develop at a much faster rate when the lights are dim and it's night time, a study suggests.
In an article published on the website of Weizmannn Institute on October 6, Monday, two scientists, Professors Yosef Yarden and Eytan Domany, discovered that tumor cells are more active and thus spread faster at night.
The cells in the body work in a very complicated network, and they communicate via receptors, which carry the biochemical messages that are then passed on from one cell to another. One of these receptors is called EGFR, or epidermal growth factor receptor. It is chiefly responsible for the cell migration and growth like tumor cells.
The second receptor, meanwhile, works with GC (glucocorticoid), a kind of organic steroid that helps determine the level of energy and metabolism of a person at different times of the day. In other words, they identify your alert level. If a person is under a very stressful situation, for example, the level of this steroid also increases.
The scientists have also learned that when the receptor that works with the steroid messenger, EGFR is suppressed.
Using this knowledge, the scientists therefore wanted to know how they relate to each other at certain times of the day.
They experimented on lab mice that had been provided with a new-generation breast cancer drug that suppresses EGFR. The medication was provided at different times of the day. Then they monitored the steroid-binding receptor and EGFR levels.
The differences in tumor sizes afterward revealed that tumors tend to spread and grow faster even with the ingested drugs at night.
This study is significant since usually cancer treatments are given when the patient is still active or during daytime. What the scientists suggest then is not a change of treatment but a modification of its schedule.