Two groups have found that certain non-cancerous cells that surround a tumour in the pancreas keep it in check, even though these cells seem to boost other types of cancer.

Raghu Kalluri at the University of Texas MD Anderson Cancer Center in Houston and his colleagues deleted fibroblast cells, which are found in connective tissue, in a mouse model of pancreatic cancer. These animals had more aggressive tumours and died sooner than those with fibroblasts. These cells seem to help the immune system to fight the tumour. In human pancreatic tissue samples, those with fewer fibroblasts were associated with lower patient survival rates.

Kenneth Olive at Columbia University in New York, Ben Stanger at the University of Pennsylvania in Philadelphia and their colleagues also found that in animals that had fewer connective tissue cells in their pancreatic tumours, the tumours grew faster and had more blood vessels than in control mice.

The results could help to explain why certain drugs that target a tumour's neighbouring cells have failed in pancreatic cancer clinical trials, the authors say.

Cancer Cell http://doi.org/szg; http://doi.org/szh (2014)