Positive and negative G1-phase cell-cycle regulators are induced in BCR-stimulated CLL cells. (A) Differentially expressed genes between unstimulated CLL cells and CLL cells stimulated for 20 hours with immobilized anti-IgM (imm-aIgM; n = 16) and analyzed on the Agilent Whole Human Genome Microarray 4x44K platform (GEO accession number GSE52776). The top 50 upregulated and top 50 downregulated genes are shown. (B) RQ-PCR analysis of an independent series of human CLL samples (n = 14) cultured for 20 hours with or without immobilized anti-IgM prior to RNA extraction. Significant differences with respect to unstimulated CLL cells are indicated with asterisks: *P < .05, **P < .01, ***P < .001. Analysis was performed using the paired Student t test or Wilcoxon signed-rank test, as appropriate. (C) Time-course analysis of changes in MYC, CCND2, CDKN1A, and CDKN2B protein expression in human CLL cells stimulated with immobilized anti-IgM. Analysis of CLL cells from 2 different patients is shown. (D) RQ-PCR analysis of changes in expression of positive and negative cell-cycle regulators in PtC-stimulated murine Eμ-TCL1–derived CLL cells expressing an anti-PtC BCR.