BTK and diffuse large B-cell lymphoma: In DLBCL, small molecular inhibitors were widely used, which include Bruton's tyrosine kinase inhibitors (BTKi, ibrutinib), PIM kinase inhibitors (PIMi, SGI-1776), histone deacetylase inhibitors (HDACi, belinostat, vorinostat), PI3K inhibitors (PI3Ki, copanlisib, buparlisib), and protein kinase C inhibitors (PKCi, sotrastaurin) (30, 36–38).