BCR and B-cell chronic lymphocytic leukemia: We performed western blots to analyze the main signaling pathways activated downstream of the BCR (e.g. ZAP70, pZAP/pSYK, pERK, pIkB) and the JAK/STAT pathway (e.g. pAKT and pSTAT6) in selected responders and non-responders amongst the ZAP70+ UM-CLL cells.