Targeted therapies directed at constitutively activated oncogenic tyrosine kinases have proven remarkably effective against cancers with fusions involving ALK, ROS1, or PDGFB, and the efficacy of this approach continues to be explored in malignancies with RET, NTRK1/2/3, FGFR1/2/3, and BRAF/CRAF fusions.
To date, becaplermin (recombinant human PDGF-BB) is the only US FDA-approved growth factor therapy, and it shows modest efficacy, is costly, and has the potential to cause cancer in patients.
Of the 15 explants tested, PDGFB was seen in six, all of which were malignant tumors; PDGFA was seen in all 15 with much higher levels expressed in malignant tumors; and TGF-beta 1 and TGF-beta 2 were seen in all 15 without a clear difference between cell types, although expression tended to be higher in malignant tumors.