= Abstract =
The identification of tumor-specific antigens has represented a critical milestone in cancer diagnosis and therapy.
Clinical research in this area for leukemia has also been driven over the past few decades by the hope that surface
antigens with restricted tissue expression would be identified. Disappointingly, only a small number of the
leukemic antigens identified to date, meet sufficient criteria to be considered viable immunophenotypic markers.
In this paper, we nominate anti-JL1 monoclonal antibody as an immunodiagnostic and immunotherapeutic
candidate for leukemia. The JL1 molecule appears to be a novel cell surface antigen, which is strictly confined
to a subpopulation of limited stages during the hematopoietic differentiation process. Despite the restricted
distribution of the JL1 antigen in normal tissues and cells, anti-JL1 monoclonal antibody specifically recognizes
various types of leukemia, irrespective of immunophenotypes. On the basis of these findings, we propose JL1
antigen as a tumor-specific marker, which shows promise as a candidate molecule for diagnosis and
immunotherapy in leukemia, and one that spares normal bone marrow stem cells.