ABSTRACT
Malignant tumors result from the outgrowth of a single transformed cell. Malignant tumors that result from the clonal outgrowth of B lymphocytes can occur at all stages of B-cell development (Fig. 19.1). These malignant B cells express clonotypic immunoglobulin molecules derived from the same immunoglobulin gene rearrangement, either on their surface or as secreted monoclonal antibody.
