Model for Bryostatin 1–induced STAT1 activation. Bryostatin 1 activates novel and classical forms of PKC, which leads to MAPK activation. MAPK activation promotes IFNγ transcription and release from the CLL cell. IFNγ acts in an autocrine manner to stimulate STAT1 signaling, which is required for further maturation of the CLL cell through a transcriptional mechanism leading to up-regulation of CD22 expression and IgM production.