TYRO3 and acute lymphoblastic leukemia: Initial data suggest that TYRO3 expression is ectopic in ALL as normal B and T cells [22] and cell lines [66] do not appear to express TYRO3; however, a thorough analysis of TAM kinase expression in B and T cells has not been reported and it is not clear whether TYRO3 is expressed in specific phenotypic subsets or during specific phases of the immune response.