HRAS and neoplasm: To address this, we adopted a mouse myoblast cell line C2C12 because this cell line can be used to compare the normal myoblast state and RMS‐like state upon oncogenic transformation.[33, 34] We prepared Control‐C2C12 and HRas/shp53‐C2C12 (transformed with the combination of HRas overexpression and tp53 knockdown) cells (Figure3A): HRas/shp53‐C2C12, but not Control‐C2C12 cells, developed a tumor that resembled ERMS in immunocompromised mouse, confirmed by histological analyses (Figure 3B).