For instance, the V561M FGFR1 gatekeeper mutation caused resistance to AZD4547 via STAT3 activation and the epithelial-mesenchymal transition in H1581 cells (79) and prolonged exposure of KMS-11 multiple myeloma cells (FGFR3 Y373C) to AZD4547 resulted in a second FGFR3 kinase domain point mutation (V555M), triggering a conformational change and preventing adequate drug binding (80). This evidence concerns the gene FGFR3 and plasma cell myeloma.