Scientists find connection between obesity and breast cancer
A common 'mantra' we hear daily is 'Watch your weight, watch what you eat'. Doing so helps lower our risk of cardiovascular disease, diabetes and premature death. But we may have another reason for it as well. New research suggests that obesity influences the prognosis of breast cancer, and specifically its propensity to spread. Presented in the journal Cancer Research, the study offers a first—hand look at a direct cause and effect relationship, and could represent a new lead for treatment.
Researchers from France's Institut national de la santé et de la recherche médicale (INSERM), in cooperation with the Université Paul Sabatier and the Centre national de la recherche scientifique (CNRS), made a groundbreaking discovery that adipose cells, what experts call adipocytes, find a niche near breast tumours.
According to the team, adipocytes can transform the characteristics of cancerous cells when they are linked with tumours, thus resulting in more aggressive cancerous cells.
Past research studies have in fact found a connection between the 'aggressiveness' of breast cancer in women, but no concrete evidence ever surfaced. In order to find the missing piece of the puzzle, the French team investigated the cross—talk between adipose cells and tumour cells.
Fat tissue, of which adipose cells are the main component, largely makes up the external part of the breast. The adipose cells, known for their ability to store and release fats, can also secrete many proteins. So the key question for the researchers was to determine whether these proteins actually contribute to breast cancer development.
Led by Philippe Valet at the Institut des Maladies Métaboliques et Cardiovasculaires (INSERM/Université Paul Sabatier) and Catherine Muller at the Institut de Pharmacologie de de Biologie Structurale (CNRS/Université Paul Sabatier), the researchers used an original co—culture system of mammary tumour cells and adipocytes, which showed a change in the secretion of some of their proteins, including inflammatory proteins like interleukin—6 (IL—6).
The team found that adipose cells interact with the tumour, triggering a rise in its 'colonisation potential' and in turn its aggressiveness. Researchers also discovered that adipocytes located near large human tumours, with ganglionic invasion, contained more IL—6. So the protein could have a hand in adipocyte—induced spread of breast cancer.
'Our results now demonstrate how adipocytes actively participate in the progression of breast cancer, orchestrated by tumour—cells,' the researchers say. 'They suggest that in the case of obesity, the adipocytes associated with breast cancer could be more likely to amplify the 'aggressive' effect of tumours. This hypothesis still needs to be verified both in mice and humans.'