In the ALK+ ALCL cell lines, we also observed an up-regulation of CDK inhibitors when JunB was knocked-down including increased expression of p27Kip1(CDKNIB) in JunB shRNA–expressing Karpas 299 and SUP-M2 cells, and p18Ink4C (CDKN2C) in Karpas 299 cells (Fig. 6C,D). Here, CDKN1B is linked to anaplastic large cell lymphoma.