we noticed that the BCR proposal also resulted in a growth of c MYC in patients cells only. This differential reaction between primary cells and cell lines may reflect higher levels of c MYC expression in cell lines when compared with patients cells. Cell lines may possibly therefore GW0742 PPAR β/δ agonist become unresponsive to help stimulation through the BCR. . The late kinetic induction of c Myc as compared to EGR 1 in patients cells may argue for a latter induction of c Myc. Whether this induction is related to expression of EGR 1 as proposed in CLL and BKS2 cells activated by CpG ODN remains to be identified. Nonetheless, our declare that EGR 1 and c MYC upregulations could play a vital part in BCR induced survival of MCL cells. The value of BCR signaling in MCL was recently investigated using a high throughput phospho proteomic process which recognized over 300 tyrosinephosphorylated proteins. Probably the most abundant haematopoietic stem cells peptides were a part of proteins constituting the BCR related signalosome. Among them, the kinases LYN and SYK were observed to be constitutively highly phosphorylated, thus reflecting a dynamic BCR signaling even in lack of antigen stimulation. The significance of the BCR signaling in MCL was also suggested through the activation of SYK probably as a result of constitutively activated signalosome made from LYN and CSK binding protein/phosphoprotein connected with glycosphingolipid enriched microdomains membrane adaptor. In the current study, we showed in a part of major MCL cells that LYN was in a constitutively active form as unveiled by phosphorylation of the active Tyr397 LYN residue. LYN is considered to be a key component Lonafarnib clinical trial of cell membrane lipid rafts. Moreover, a part of transmembrane proteins with aberrant expression was identified in MCL plasma membranes. Particularly, Cbp/PAG that participates to the negative regulation of LYN in resting T cells through CSK employment was underexpressed in MCL primary cells in comparison to normal B cells. This expression of Cbp/PAG could hence subscribe to the constitutive activation of LYN in MCL cells. Dasatinib, a double BCR/ABL and SFK inhibitor, has shown its efficacy in inhibiting cell proliferation of lymphoma B cells exhibiting a constitutive activation of Src kinase. Yang et al. shown that inhibition of the Src SYK PLCg2 route by dasatinib caused G1 arrest in DLBCL. In the present study, we confirmed a constitutive and BCR induced phosphorylation of LYN, ergo justifying the rationale to gauge the impact of dasatinib in MCL cell survival. We showed that dasatinib, which targeted the ATP binding pocket of LYN, inhibited phosphorylation of Tyr397 LYN probably by blocking its trans autophosphorylation.. We also showed for the very first time that dasatinib induced apoptosis of key MCL cells and suppressed BCRinduced emergency after antigen triggering at nanomolar range.