Studies have shown that stress can affect the immune system. In cancer patients this stress can also affect a tumor's ability to grow. However, the biological mechanisms that underlie such associations are not well understood. Now, researchers at Fox Chase find that poor psychosocial functioning is associated with greater vascular endothelial growth factor expression -- a signaling protein that stimulates tumor growth and is also associated with shorter disease-free survival in head and neck cancer patients.

Read more http://www.eurekalert.org/pub_releases/2011-04/fccc-sad042011.php