“…Most studies on the involvement of FGF proteins in the development of drug resistance involve FGF1 and FGF2, while there are a few reports on the role of other FGFs in this process, including FGF4, FGF5, FGF9, FGF10, FGF13, and FGF19 [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. Overexpression of FGF receptors in cancer cells has also been observed with a concomitant reduction in response to protein kinase inhibitors (including RTKs) or endocrine therapy ( Table 1 ) [ 39 , 45 , 46 , 47 , 48 , 49 , 50 ]. To investigate the involvement of FGF proteins and their receptors in the process of chemoresistance, particular attention has been paid to FGFR-dependent signaling pathways and their downstream targets, which can lead to deregulation of a number of biological processes, including apoptosis and metastasis.…”