Editing Paracrine signaling (section)

====RTK receptor and cancer====
Paracrine signaling of growth factors between nearby cells has been shown to exacerbate [[carcinogenesis]].  In fact, mutant forms of a single RTK may play a causal role in very different types of cancer.  The Kit [[proto-oncogene]] encodes a tyrosine kinase receptor whose ligand is a paracrine protein called stem cell factor (SCF), which is important in [[hematopoiesis]] (formation of cells in blood).<ref name="Zsebo">{{cite journal |doi=10.1016/0092-8674(90)90302-U |title=Stem cell factor is encoded at the SI locus of the mouse and is the ligand for the c-kit tyrosine kinase receptor |year=1990 |last1=Zsebo |first1=Krisztina M. |last2=Williams |first2=David A. |last3=Geissler |first3=Edwin N. |last4=Broudy |first4=Virginia C. |last5=Martin |first5=Francis H. |last6=Atkins |first6=Harry L. |last7=Hsu |first7=Rou-Yin |last8=Birkett |first8=Neal C. |last9=Okino |first9=Kenneth H. |journal=Cell |volume=63 |pages=213–24 |pmid=1698556 |issue=1 |last10=Murdock |first10=Douglas C. |last11=Jacobsen |first11=Frederick W. |last12=Langley |first12=Keith E. |last13=Smith |first13=Kent A. |last14=Takeish |first14=Takashi |last15=Cattanach |first15=Bruce M. |last16=Galli |first16=Stephen J. |last17=Suggs |first17=Sidney V.|s2cid=39924379 }}</ref>  The Kit receptor and related tyrosine kinase receptors actually are inhibitory and effectively suppresses receptor firing.  Mutant forms of the Kit receptor, which fire constitutively in a ligand-independent fashion, are found in a diverse array of cancerous malignancies.<ref name="Rönnstrand">{{cite journal |doi=10.1007/s00018-004-4189-6 |title=Signal transduction via the stem cell factor receptor/c-Kit |year=2004 |last1=Rönnstrand |first1=L. |journal=Cellular and Molecular Life Sciences |volume=61 |issue=19–20 |pages=2535–48 |pmid=15526160|s2cid=2602233 |pmc=11924424 }}</ref>