In cell cultures, the stress hormone norepinephrine promotes the signals that cause certain tumor cells to grow and spread. This means that stress hormones may play a completely different role in cancer development than researchers once thought.
Researchers looking at multiple myeloma, one of several types of cancers of the blood, found that a tumor cell line known as FLAM-76 responded strongly to the hormone. The norepinephrine bonded to receptors on the surface of the cells, causing them to produce a compound known as vascular endothelial growth factor (VEGF) that is key to the formation of the new blood vessels which the tumor needs in order to grow.
The researchers are now working with other forms of cancer to test the effects of stress hormones like norepinephrine on their growth. In the past, it was believed that stress hormones worsened cancer by weakening the immune system.
* Science Daily November 21, 2007