R-FC vs FC effect in terms of PFS in relation to PTK2 expression level (high: >median vs low: ≤median) in the CLL8 cohort of patients. The curves represent Kaplan-Meier estimates of probability of PFS for CLL8 patients in treatment (R-FC, red; FC, black) and PTK2 expression level (PTK2 high, solid; PTK2 low, dashed) subgroups.