SYK and asthma: Finally, inhibitors of non-RTKs, such as stem cell growth factor receptor (c-kit), spleen tyrosine kinase (SYK), the proto-oncogene tyrosine-protein kinase Src, and Janus kinase (JAK), have also been investigated in rodent models of asthma but have not yet progressed to studies in humans105,106,167–171.