ABSTRACT
This chapter presents a brief background regarding the basic application of molecular biology in diagnostic hematopathology. Chronic myeloid leukemia is a neoplasm of the pluripotent hematopoietic stem cell characterized by the accumulation of mature granulocytes and their precursors in the bone marrow and the blood. Virtually all B-lineage acute lymphoblastic leukemias (ALLs) have immunoglobulin (Ig) heavy-chain gene rearrangement; about 40% and only 20% have κ and λ light-chain gene rearrangements, respectively. Likewise, the majority of T-ALLs demonstrate T-cell receptor gene rearrangements. The immune system has evolved to provide antibody molecules with different combining sites, diverse to a degree to recognize a myriad of antigens. In the germline configuration, the single Ig heavy-chain locus consists of a several segments. Analysis of the genomic organization of the Ig and T-cell receptor gene loci has become a sensitive tool to assess clonality and to establish cell lineage of lymphoproliferative disorders.
