Dysregulation of the protein tyrosine kinase LCK in lymphoproliferative disorders and in other neoplasias

Initially identified as a T-cell specific member of the Src family of prote in tyrosine kinases, Lck has become the object of intensive investigations which have revealed a key role for this kinase in the central processes con trolling T-cell development, activation, proliferation and survival. Experi mental evidence of the oncogenic potential of Lck, together with the identi fication of defects in the regulation of Lck expression or activity in T-ce ll leukemias, suggests that dysregulation of Lck might play a role in neopl astic transformation. Here we review the data documenting a potential role for this kinase in the initiation and maintenance of the transformed state in human cancers.