BTK and mantle cell lymphoma: In line with these findings the BTK inhibitors ibrutinib and acalabrutinib reduced the growth of MCL cell lines JeKo-1, Mino-1, and Rec-1, but hardly affected the growth of Z-138, Maver-1, and Granta-519 even though BTK is expressed and active in these cell lines (Fig. 1A, Supplementary Fig. 1A).