Correlation of MARCKS expression with response to BTK inhibition. (A) Acalabrutinib-induced lymphocytosis dependent on MARCKS expression determined by RNA-seq (n = 20: 18 UM-CLL, 2 M-CLL). (B) ALC dependent on MARCKS expression after cycle 1 and cycle 2 of acalabrutinib treatment. (C-D) Acalabrutinib induced change in nodal disease in patients with below and above median MARCKS expression. (E) Expression of MARCKS during 6 cycles of treatment with acalabrutinib in 20 patients. Log₂ fold change from baseline is shown for each patient (mean log₂ fold change, −0.8675 after cycle 1). Paired Student t test. SPD, sum of the products of lymph node diameters.