Growth factors are ligands that cause growth of cells.  As cancer is a problem of cell growth we can assume that these growth factors may play a role in its proliferation.  Most growth factors are expressed locally and exert their action within the same tissues.  They can be released from cells in an inactive form and require activation before their biological effects can occur.

We group growth factors into similar families and here are the families:

<b>Growth Factor Family<b> 