Breast cancer is more common and aggressive in obese people, researchers claim. While prior studies have drawn the link, experts haven't been able to pinpoint why overweight women are more prone to the disease.
Now, an international team of researchers believe their findings can shed more light on the association.
Researchers from the University of Miami in the U.S. and Granada's University Hospital Center found that fat around a tumour (peritumoral fat) allows the expansion and invasion of cancer stem cells (CSCs) which are responsible of the onset and growth of the tumour.
They also claimed that obesity-related fat causes local inflammation and prevents adipocytes, the cells forming that fat, from maturing.
Cancer stem cells are found in tumors in small quantities, and they are responsible for the metastasis, which is the spreading in parts of the body far from the original tumor.
Conventional chemotherapy and radiotherapy treatments are not capable of eliminating these cells.
As a result, it is common that, after the first response to treatment, many cancer patients suffer a relapse, the researchers said. Accordingly, they warn that the consequences of the obesity epidemic on cancer morbidity and mortality are very serious.
It is estimated that nowadays, up to 20 percent of cancer-related deaths may be because of obesity.
The researchers added that obese women have a greater risk of suffering breast cancer after going through the menopause. And the disease progresses much faster in those women—regardless of their age.
However, the researchers admit that the mechanisms by which obesity contributes to the development and progression of cancer are not yet absolutely clear.
The findings were first published in the journal Cancer Research.