Links between Night Shift Work and Cancer: U of L researchers Seek Genetic Connections
Links between Night Shift Work and Cancer: U of L researchers Seek Genetic Connections

November 29, 2012


Dr. Olga Kovalchuk, a medical doctor and biological Sciences researcher at the University of Lethbridge, is studying how something as simple as sleep disruption could make cells vulnerable to cancer.

“The disruption of circadian rhythms (a sleep-wake cycle) due to shift work or exposure to light at night has recently been suggested as a breast carcinogen. Elevated rates of breast cancer have been reported in groups of shift workers in countries all over the world, including Canada,” Kovalchuk said.

Circadian rhythms are the equivalent of a person’s ‘internal clock,’ and help govern such things as sleep patterns, alertness and other factors. Circadian rhythms are found in most living things, from bacteria to plants and animals.

They follow a set pattern that, if shifted around, cause a number of biological processes to change, and not always for the better – as any sleep-deprived new parent or shift worker adjusting to a new schedule can attest.

To tease out the minute changes in the genetic markers that make up the road map to solving this challenge, Kovalchuk, a Professor and Board of Governors’ Research Chair, CIHR Chair in Gender and Health, will employ epigenetics – the study of how an individual gene can go wrong or not work properly over a person’s lifetime.

“The precise mechanisms of breast cancer induced by circadian rhythm disruption are elusive,” Kovalchuk said. “In recent years, the role of epigenetic changes as a cause of breast cancer has been increasingly recognized, so we are going to attack this challenge from that perspective.”

Epigenetics (which means ‘beyond genetics’ in Latin) is the study of how individual genes and components of individual genes can change in response to environmental conditions or other factors.

In addition to the hard-wired traits in DNA, epigenetic changes can occur in response to a change in lifestyle or other trigger, and can be passed from one generation to another.

With colleague and neuroscientist Dr. Robert Macdonald at the Canadian Centre for Behavioural Neuroscience, also at the U of L, Kovalchuk and their respective lab teams will develop a model to test how changes in genetic structure are brought about by sleep or circadian disruption. They will also look at how those epigenetic changes affect cells -- which in turn would make them a target for cancer.

The group will study mammary glands and look at the genetic ‘switches’ that are turned on or off in response to the circadian pattern changes.

Kovalchuk recently received a significant award from the Canadian Breast Cancer Foundation – Prairies/NWT Region Research Grant program to begin this project.

Her $375,000 award was part of a 19-project, $6.8 million announcement made in early November by the Canadian Breast Cancer Foundation – Prairies/NWT Region. The CBCF supports research projects that demonstrate high degrees of innovation or novelty in breast cancer research. (

Kovalchuk, who is also a medical doctor, is no stranger to cancer research or exposure to cancer-causing environments.

She was inspired to take on a career in medicine by her experience as a high school student in the Ukraine in 1986, while living only 600 kilometres from Chernobyl, the site of the worst nuclear accident in history.

Since 1995, Kovalchuk has been involved in the detailed analysis of the genetic consequences of the Chernobyl accident in the Ukraine, and is currently researching the mechanisms by which radiation induces cancer.

Her research programs in the Ukraine, Switzerland and at the University of Lethbridge have focused on the effects of long-term exposure to radiation, and how that exposure changes cellular and molecular structures in animals and people.

She also studies ‘bystander effect’ of radiation exposure on cells near to areas under treatment by radiation therapy.

Her work examines how radiation induces secondary tumours in cancer patients, the different effects radiation has on women and men, and what can be done to protect the children of radiation-exposed parents from contracting cancer.

In addition to continued funding and support from numerous agencies, including the Natural Sciences and Engineering Research Council, Alberta Cancer Foundation, Canadian Breast Cancer Foundation and others, she was recently appointed a Chair of the Institute for Gender and Health by the Canadian Institute for Health Research.

With a cross-disciplinary team of researchers at the University of Lethbridge and other centres worldwide, Kovalchuk and her colleagues are developing a unique research centre at the U of L to study epigenetics. (

She was recently named one of Canada’s “Top 40 under 40” ( and as one of Canada’s 25 top Women of Influence ( As well, she is active with her family in supporting charitable causes that focus on cancer prevention and awareness.

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Dr. Olga Kovalchuk
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