CDKN1B and lung adenocarcinoma: Similar to shRNA-mediated BMI-1 inhibition in breast and lung adenocarcinoma cells [31, 32], the growth-inhibiting effect of PTC-209 was associated with deregulation of CCND1, MYC, CDKN1A and CDKN1B. These genes are known to be implicated in the proliferation of MM cells and their deregulation therefore likely explains the accumulation of cells in the G1 phase and the impaired entry into the S and G2M phase of the cell cycle.