CDK6 and meningioma: As for genes associated with cell cycle pathway, the results of qRT-PCR showed up-regulation of CCND1 (6.28-fold), CDK6 (6.03-fold), and E2F3 (4.26-fold) in fibroblastic meningiomas, and down-regulation of CDKN1A (8.64-fold), CDKN2A (3.21-fold), and CDKN2B (4.53-fold), suggesting accelerated G1/S progression and promoted proliferation of tumor cells (Figure 2A, 2B).