BCL2 and mantle cell lymphoma: Because Cyclin D1 interacts with other signaling pathways including BCR/PI3K/AKT/mammalian target of rapamycin (mTOR), nuclear factor-κB (NF-κB), tumor necrosis factor (TNF), Hedgehog and WNT pathways, and the Bcl-2 family of apoptosis regulators, it is not surprising that Cyclin D1 is at the center of the pathogenesis of MCL, enhancing tumor proliferation, facilitating evasion of apoptosis, and reducing immune control [40].