Know more

Our use of cookies

Cookies are a set of data stored on a user’s device when the user browses a web site. The data is in a file containing an ID number, the name of the server which deposited it and, in some cases, an expiry date. We use cookies to record information about your visit, language of preference, and other parameters on the site in order to optimise your next visit and make the site even more useful to you.

To improve your experience, we use cookies to store certain browsing information and provide secure navigation, and to collect statistics with a view to improve the site’s features. For a complete list of the cookies we use, download “Ghostery”, a free plug-in for browsers which can detect, and, in some cases, block cookies.

Ghostery is available here for free: https://www.ghostery.com/fr/products/

You can also visit the CNIL web site for instructions on how to configure your browser to manage cookie storage on your device.

In the case of third-party advertising cookies, you can also visit the following site: http://www.youronlinechoices.com/fr/controler-ses-cookies/, offered by digital advertising professionals within the European Digital Advertising Alliance (EDAA). From the site, you can deny or accept the cookies used by advertising professionals who are members.

It is also possible to block certain third-party cookies directly via publishers:

Cookie type

Means of blocking

Analytical and performance cookies

Realytics
Google Analytics
Spoteffects
Optimizely

Targeted advertising cookies

DoubleClick
Mediarithmics

The following types of cookies may be used on our websites:

Mandatory cookies

Functional cookies

Social media and advertising cookies

These cookies are needed to ensure the proper functioning of the site and cannot be disabled. They help ensure a secure connection and the basic availability of our website.

These cookies allow us to analyse site use in order to measure and optimise performance. They allow us to store your sign-in information and display the different components of our website in a more coherent way.

These cookies are used by advertising agencies such as Google and by social media sites such as LinkedIn and Facebook. Among other things, they allow pages to be shared on social media, the posting of comments, and the publication (on our site or elsewhere) of ads that reflect your centres of interest.

Our EZPublish content management system (CMS) uses CAS and PHP session cookies and the New Relic cookie for monitoring purposes (IP, response times).

These cookies are deleted at the end of the browsing session (when you log off or close your browser window)

Our EZPublish content management system (CMS) uses the XiTi cookie to measure traffic. Our service provider is AT Internet. This company stores data (IPs, date and time of access, length of the visit and pages viewed) for six months.

Our EZPublish content management system (CMS) does not use this type of cookie.

For more information about the cookies we use, contact INRA’s Data Protection Officer by email at cil-dpo@inra.fr or by post at:

INRA
24, chemin de Borde Rouge –Auzeville – CS52627
31326 Castanet Tolosan CEDEX - France

Dernière mise à jour : Mai 2018

Menu Logo Principal AgroParisTech Université Paris-Saclay UVSQ ANSES CNRS ENVA

Home page

Breast Cancer: a chronic disturbance of the circadien rythme increases the dissemination of cancer cells

24 June 2020

@Pixabay
Breast cancer is the most wide-spread cancer in the world and one of the main causes of death in women. A study implicating scientists from the Paris-Saclay University, INSERM and INRAE just established a link between night shift working and an increased risk of cancer, suggesting that disruption of circadian rythms could make tumors more agressive. This study was published in the journal Nature Communications on Wednesday, June 24, 2020.

Breast cancer is the most frequent cancer in women. The cumulated risk that a woman develops breast cancer is approximately 5% in the world, with a risk of death of 1,4%. In 2018, more than 2 million new cases were diagnosed, representing about 25% of cancer cases in the world.

Different epidemiological studies carried forth recently have improved our understanding of the factors that increase the risk of developing breast cancer. We know that less than 10% of these cases are hereditary and have a genetic origin. In most cases, the different risk factors identified are behavioural factors associated with for example poor nutrition or consumption of alcohol; hormonal factors associated with taking a contraceptive pill at a young age or for a long time or hormonal treatments taken during menopause; and finally environmental factors such as air polution or altered light/dark cycles like those encountered by nightshift workers.

It is this effect of chronic light/dark alteration on the development of breast tumors that scientists from the ONCOSTEM (U 935 Inserm/UPSaclay) and the GABI (INRAE/AgroParisTech/UPSaclay, Jouy-en-Josas) laboratories studied.

Scientists used a mouse model that spontaneously develops mammary gland tumors. The animals underwent chronic light/dark differences that experimentally reproduced a rythm of nightshift workers (an alternating day shift and night shift or jet-lag conditions). The scientists then oberved that the circadian disruption[1] had a significant impact on the development of mammary gland tumors. This disruption of the circadian rythm increased the dissemination of cancer cells and the formation of metastases in these animal models.

This study also reveals that chronic disruptions in the circadian rythm makes the immune system more permissive to the dissemination of cancer cells by modifying the tumor's micro-environment. Thus, an increase in the Cxcl5 chemokine in the tumors leads to an increased infiltration of myeloid CXCR2 + cells that favor an immunosuppressing environment. These negative effects may be corrected using a CXCR2/CXCL5 pathway inhibitor, therefore limiting the effects of circadian stress on tumor progression.

These experimental results confirm epidemiological studies showing that premenopaused women exposed through their work to disruption of light/dark cycles over long periods of time are particularly exposed to more agressive breast cancers.

These studies were financed in part by the following associations and fondations: Vaincre le Cancer, ICIG (Institut de Cancérologie et d’Immunogénétique), Fondation de l'Avenir, GEFLUC-IdF Les Entreprises contre le cancer. 

 

[1]The circadian ryhtm is defined by an alternation of a waking period, which one is awake and sleep, which lasts approximately 24 hours.

See also

Bibliography

Eva Hadadi, William Taylor, Xiaomei Li, Yetki Aslan, Marthe Villote, Julie Rivière, Gaelle Duvallet, Charlotte Auriau, Sandrine Dulong, Isabelle Raymond Letron, Sylvain Provot, Annelise Bennaceur-Griscelliand Hervé Acloque : Chronic circadian disruption modulates breast cancer stemness and immune microenvironment to drive metastasis in mice, Nature Communication 11, 3193 (2020) . DOI : 10.1038/s41467-020-16890-6