SYK and B-cell non-Hodgkin lymphoma: We next sought direct and unequivocal genetic evidence for a cell cycle regulatory role of SYK in lymphoid cells using DT40 chicken B-cell line and its SYK-deficient DT40 chicken B-cell lymphoma clones that were established by homologous recombination knockout (Uckun et al., 1996, Uckun et al., 2010a).