Thus in CLL B-cells for patients P1, P2, P6, and P12, there were detectable levels at baseline and then increasing levels of Btk mRNA over time while P3, P5, and P8 had detectable baseline Btk mRNA levels which after an initial increase dropped gradually over time but still were detectable at the last study time point. Here, BTK is linked to B-cell chronic lymphocytic leukemia.