Lyn, an important component of B-cell receptor (BCR) signalling and known for its role in activation and proliferation of B Cells, also has potential to negatively regulate BCR signaling.

Higher levels of Lyn in hCLL associated with shorter treatment free survival but not well understood.

Authors compared Eµ-TCL1 transgenic LYN-deficient mice (TCL1+/wtLYN-/-) with TCL1+/wtLYNwt/wt. TCL1+/wtLYN-/- mice showed significantly reduced number of malignant B cells in the peripheral blood, and decrease infiltration of lymphoid tissues by these cells. In contrast, ex vivo, these B cells showed enhanced proliferation and better survival compared to TCL1+/wtLYNwt/wt mice.

TCL1+/wtLYN-/- mice posssibly developed skewed micro environment which might contribute to CLL down regulation, though mechanism of finding not clear.