HERE is yet another reason to stay at a healthy weight. Stem cells from the fat of women with obesity boost the growth of breast tumours more than cells from slim women.

To probe the link between obesity and breast cancer, Bruce Bunnell at Tulane University in New Orleans enlisted the help of 24 women having liposuction, half of whom were obese.

Mice were injected with a mix of breast cancer cells and stem cells from the women’s fat. After 36 days, the mice had developed tumours. Those associated with stem cells from obese women were 1.78 cubic centimetres in volume, more than twice the size of those associated with the stem cells from the slim women (Breast Cancer Research, doi.org/pt3).

Bunnell thinks excess fat causes inflammation, making stem cells release growth factors that help the tumour expand.

This article appeared in print under the headline “Cancer fattens fast with ‘fat’ stem cells”