Quantitative analysis of a new marker for common acute lymphoblastic leukemia detected by two-dimensional electrophoresis.

A major subtype of childhood lymphoblastic leukemia has been previously defined on the basis of expression of a cell surface marker referred to as the common acute lymphoblastic leukemia antigen. In this study we provide evidence that leukemic cells from most of the patients with common acute lymphoblastic leukemia contain a cytosolic polypeptide designated L4, the occurrence of which is strongly correlated with the expression of the common acute lymphoblastic leukemia antigen. The detection and quantitation of L4 was accomplished by analysis of cellular polypeptides resolved by two-dimensional polyacrylamide gel electrophoresis. This approach provides a powerful tool for the delineation of distinct polypeptides corresponding to different types of leukemia and complements immunological analysis of the cell surface marker phenotype.