FGFR1 and neoplasm: Several activating mutations in different FGFR isoforms such as FGFR1 N546K [50], FGFR3 K650E [51], and FGFR4 G388A [52] have been reported in ES samples as possible enhancers of tumor aggressiveness in comparison with the FGFR wild-type tumors.