A protein made by connective-tissue cells causes mechanical changes in tissue structure that help cancers to spread around the body.

Jacky Goetz and Miguel Del Pozo at the Spanish National Center for Cardiovascular Research in Madrid and their colleagues found that stromal fibroblast cells surrounding many human cancers express high levels of the protein CAV1. Mouse fibroblasts expressing CAV1 activate the enzyme Rho, which causes the cells to stretch out (pictured). In three-dimensional gel matrices in vitro, the elongated fibroblasts formed stiff, parallel-fibre networks through which cancer cells moved rapidly.

When the authors injected mouse fibroblasts lacking CAV1 and breast-cancer cells into mice, tumours were minimally invasive. But when they used CAV1-expressing fibroblasts, tumours grew more rapidly and invaded multiple organs.

Credit: J. GOETZ

Cell doi:10.1016/j.cell.2011.05.040 (2011)