Akt is preferentially activated in the blastoid variant of MCL and in MCL cell lines and is associated with phosphorylation of several downstream targets. (A) Western blot analysis for activated p-Akt (Ser473) in MCL cases and cell lines (Granta 519 [G], NCEB-1 [N], REC-1 [R], Z138C [Z]). High levels of p-Akt were detected in 12 of 12 blastoid MCLs (cases 1-12) and in the 4 cell lines, whereas only 5 of 19 typical MCLs displayed p-Akt—3 at high levels (cases 14, 16, and 18) and 2 at low levels (cases 24 and 27). Actin is shown as loading control. (B) Western blot analyses of downstream Akt targets shown for representative MCL cases, the Granta 519 cell line, and a follicular hyperplasia control (FHP). Blastoid variants (cases 1-4) and the Granta 519 cell line show high levels of p-Akt and multiple phosphorylated downstream targets (p-FRKHL-1, p-MDM2, p-p27^kip1, p-Bad), compared with typical MCL (cases 22-24). The low activation of Akt in case 24 results in modest phosphorylation of the downstream targets. Note that GSK-3β, a classic Akt target, is phosphorylated in both p-Akt+ and p-Akt-cases. The negative control follicular hyperplasia (FHP) shows no activation of the Akt pathway. Cyclin D1 is strongly positive in all MCL cases. Actin shows equal loading of protein for each lane.