NFKB1 and mantle cell lymphoma: Primary resistance is mainly mediated though genetic lesions in the alternative NF-κΒ pathway as shown in human cell lines and MCL samples with mutations in TRAF2 and BIRC3 [68] and also, through activation of compensatory signaling pathways such as the PI3K/AKT/mTOR, MEK/ERK and canonical NF-κB pathway.