Solid stress and tumour mechanobiology models

Stylianopoulos, Jain and colleagues measured and modelled the mechanical stress a growing tumour builds up as it pushes against and is confined by surrounding tissue; the stress compresses blood and lymphatic vessels, raising hypoxia and interstitial pressure and blocking drug delivery, especially in pancreatic cancer. Poroelastic and growth-mechanics models predict that reducing matrix stiffness or cell density, for example with losartan (an angiotensin blocker that reduces collagen), decompresses vessels; a phase 2 trial of losartan with chemoradiation in pancreatic cancer reported high resection rates, and larger trials followed. Mechanics also feeds models of invasion and of how stiffness itself signals cells to grow.