Taken together, these results demonstrate that KIN-8194 inhibits the proliferation of BTKi-sensitive and -insensitive MCL cell lines, with the exception of the HCK-negative atypical MCL cell line Z-138, and also impedes the ATP-activity and viability of primary MCL samples, whereas ibrutinib only had modest effects. The gene discussed is IBTK; the disease is mantle cell lymphoma.