RB1 and mantle cell lymphoma: MiR-29 family members are critical regulators of extracellular matrix (ECM) proteins and signaling pathways associated with fibrosis via targeting of collagens, fibrillins, and elastin.MiR-29 inhibition activated CDK4/CDK6 and RB1 in MCL. Low expression of miR-29 was associated with poor prognosis in MCL.