RAPGEFL1 and lung adenocarcinoma: Furthermore, 1 gene fusion event involving fibroblast growth factor receptor 4 (FGFR4) and the Rap guanine nucleotide exchange factor like 1 gene (RAPGEFL1) (FGFR4 F17: RAPGEFL1 R4) was detected in a lung adenocarcinoma patient (P26) (Figure 2C), which has not been previously documented, and therefore further validation of its function is necessary in future research.