 The reason for this phenotype was identified by a genetic fate mapping approach, showing that Syk is expressed in myeloid cells which orchestrate the proper separation of lymphatics and blood system during embryogenesis and beyond.Thus, Syk is an essential regulator of the lymphatic system development in mice.Abnormal function of Syk has been implicated in several instances of hematopoeitic malignancies including translocations involving Itk and Tel.