Inhibition of ERK1/2 using a small molecule inhibitor or ERK1/2-specific siRNA inhibited the capacity of Wnt5a to enhance of CLL-cell proliferation, which also could be inhibited by cirmtuzumab, demonstrating that the capacity of Wnt5a to enhance CLL-cell proliferation is dependent on ROR1 and ERK1/2. Here, WNT5A is linked to B-cell chronic lymphocytic leukemia.