LTA and neoplasm: To further validate the resistance of MPI cells to malignant transformation, we introduced luciferase into mouse (MSFHRAS\SV40LT) and MPI (MPI-SFHRAS\SV40LT) fibroblasts expressing HRAS(G12V) and SV40 LT, as the intensity of the luciferase fluorescence can be used to reflect the size of the xenograft or tumor.