BTK and lymphoma: Inhibitors targeting key pathways, including spleen tyrosine kinase (SYK), Bruton’s tyrosine kinase (BTK), phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR), Janus kinase-signal transducer and activator of transcription (JAK-STAT), NOTCH, NF-κB and ubiquitin-proteasome pathway (UPP), have been applied to treat lymphomas.