Significant enrichment of mutated genes of the RAS and PI3K-Akt signalling pathways was reported in thymomas (AKT3, ALK, CSF1R, FGFR4, KRAS, NRAS, HRAS, PIK3CA), and their role in thymoma development was suggested [30,31,35,38,44,49]. This evidence concerns the gene CSF1R and thymoma.