tokens: We examined MEK1 and MEK2 levels by western blot to confirm decreased protein in MUC1 siRNA - treated cells ( Figure 3a ) , and found that not only were total MEK1 / 2 levels lower in 468 . siMUC1 and BT . siMUC1 compared to controls ( 0 . 48 and 0 . 68 relative to siLuc , respectively ) , but so were the basal amounts of active ( phosphorylated ) MEK1 / 2 ( pMEK1 / 2 ; 0 . 12 and 0 . 42 relative to siLuc , respectively ) .