AKT1 and cancer: (b) In the case of Akt/PKB, expression of total Akt/PKB was neither up nor down-regulated by any of the anti-cancer agents tested (Figure 6a), but the expression of Akt/PKB phosphorylated at Thr308 was down-regulated by 4-hydroxytamoxifen and dexamethasone (Figure 6b).