MAP3K1 and neoplasm: As shown in Figure 9, tumor cells transfected with MEKK1-MiLV or pCMV/MEKK1 plasmid both significantly suppressed the growth of B95-8 subcutaneous tumors when compared with that of control (not transfected) (p<0.01), suggesting that MEKK1 gene could enhance the in vivo sensitivity of EBV positive tumor cells to GCV/NaB.