Unexpected lambda chain expression in lymphocytic malignancy.

Specific chromosome changes occur in the initiation and progression of cancer. A translocation between chromosomes 14 and 18 arises as a primary cytogenetic event in the formation of non-Hodgkin, non-Burkitt lymphomas (BL), while a translocation between chromosomes 2 and 8 is seen in BL and BL-type acute lymphocytic leukemia (ALL-L3) with expression of kappa (kappa) light immunoglobulin chains. These two translocations were detected in a lymphocytic malignancy expressing not kappa, but lambda (lambda) light chains. The anomalous light chain expression, it appears, provides the key clue indicating that the translocation between chromosomes 14 and 18 arose first during lymphoma formation in a cell committed to lambda chain synthesis and the translocation between chromosomes 2 and 8 occurred in the transformation to ALL. This sequence of cytogenetic events is consistent with the clinical course from lymphocytic lymphoma to ALL, the immunologic phenotype of the malignancy, and the concept of a cascade of chromosome changes eventuating in aggressive cancer.