New research links stress, light exposure to breast cancer

New research from the University of the Philippines-Diliman College of Science (UPD-CS) has found a conclusive link between stress, altered light-dark cycles—such as in the cases of night shift workers and frequent international travelers—and breast cancer.

Image by Weand Ybañez

Molecular biologist Dr. Pia Bagamasbad and her student, Weand Ybañez, at the UPD-National Institute of Molecular Biology and Biotechnology (NIMBB) discovered a gene called Krüppel-like factor 9 (KLF9) that suppresses tumor growth and links the effects of stress, regulation of the light-dark cycle, and breast cancer. In their study, the researchers found that KLF9 is suppressed in breast tumors compared to normal breast tissue and that KLF9 is affected by stress hormones and changes in a person’s exposure to light and dark.

Normal body function involves a regular 24-hour pattern of biological activity, called the “circadian cycle,” which is mainly controlled by the 12-hour light-dark cycle that, in turn, regulates several bodily functions such as sleeping and waking, digestion, and the action of various hormones at different times of the day.

In normal breast tissue, the researchers found that KLF9 exhibits a cyclical pattern as part of a healthy circadian cycle. However, this regular pattern is lost in highly aggressive breast cancer. Since KLF9 suppresses the growth and spread of breast cancer cells, these research findings show a direct link between stress hormones and changes in the circadian cycle—such as lack of sleep—on breast cancer risk and development.

The NIMBB research team underscored the value of maintaining a regular circadian cycle in their study, warning of the negative effects of disruptions in the regularity of the circadian cycle: “Circadian disruption is an emerging driver of breast cancer, with epidemiological studies linking shift work and chronic jet lag to increased breast cancer risk,” they noted in their research paper, which was published last February 23 in the journal Cancer Cell International.

“These findings have potentially far-reaching implications not just on our understanding of how cancer develops and spreads and how it can be effectively managed, but more importantly emphasize the need for policies and interventions that can safeguard the overall health and wellness of women working in industries involving disruption in the regular circadian cycle”, Bagamasbad said. (UPD-CS Science Communications)