17-78 PDGF is encoded by a gene that can cause cancer when expressed inappropriately Why then do cancers not arise at wounds when PDGF is released from platelets?

Answer 1

The on-demand, limited release of PDGF at a wound site

triggers cell division of neighboring cells for a limited

amount of time, until the PDGF is degraded. This is

different from the continuous release of PDGF from mutant

cells, where PDGF is made in an uncontrolled way at high

levels. Moreover, the mutant cells that make PDGF often

inappropriately express their own PDGF receptor, so

that they can stimulate their own proliferation, thereby

promoting the development of cancer

Answer 2

Cancers typically arise when there are genetic mutations that cause uncontrolled cell growth and division. When PDGF is released at wounds, its role is to promote cell growth and repair, which is a normal process. The levels of PDGF released during wound healing are tightly regulated and do not lead to the genetic mutations required for cancer development.