Many growth factors may not be growth factors
Prehn, R.T.
Cancer Research 52(3): 501-507
1992
ISSN/ISBN: 0008-5472 PMID: 1732036 Document Number: 396193
Both organ growth and tumor growth are dependent upon a biased ratio of cell births to cell deaths; this ratio is independent of the frequency of mitosis. Thus, so-called growth factors that affect only the frequency of mitosis are not really growth factors. I shall advance two hypotheses: that the normal adult ratio of cell births to cell deaths is maintained by the activity of a factor or factors produced by the stem cells; and that the differentiating cells, as well as the stem cells, produce a different factor that limits the frequency of mitosis.