Growth factors that are produced locally at the wound site and systemi
cally from distant sources may elicit inhibitory or stimulatory respon
ses depending on interactions with other factors and the cellular envi
ronment into which they are liberated. Growth factors released from ma
crophages, neutrophils, lymphocytes, platelets, and fibroblasts bind t
o target cells via specific cell-surface receptors inducing cells to m
igrate, divide, or produce other factors required for wound healing. S
tructural similarities between cell receptors may explain cross-reacti
vity between substances. Systemic growth factors, such as growth hormo
ne and local epidermal growth factor, fibroblast growth factor, platel
et-derived growth factor, and transforming growth factor beta have all
been shown to enhance wound healing. Further, growth factors have bee
n shown to have a distinct role in catabolic and malnourished patients
as well as in patients with cancer. Clinical trials with growth facto
rs have demonstrated efficacy, and specific uses for those particular
factors may become an accepted mode of therapy producing important dif
ferences in outcome.