GSK3B and cancer: For instance, two pancreatic cancer cell lines, PANC1 and ASPC1, exhibit amplification of AKT and high levels of AKT RNA and protein [43] but also highly active GSK-3β suggesting that, although some pools of GSK-3 can be phosphorylated by AKT at Ser21/Ser9 and inhibited, other pools of GSK-3 may remain active in cancer cells [31].