The use of enzyme marker analysis for subclassification of acute lymphocytic leukemia in childhood.

Subclassification of acute lymphocytic leukemias in childhood by multiple marker analysis has proven the heterogeneity of this disease and this methodology has led to a better understanding of the cell-biological basis of ALL. Enzyme markers have become important tools in multiple marker analysis. This is especially true for TdT, purine metabolic enzymes, hexosaminidase I, acid phosphatase and carboxylic esterases. In spite of sophisticated methods and encouraging results multiple marker analysis has not been totally satisfactory in defining patients at risk. The same is true for a risk score established by clinical data. More efforts in the future are necessary for combining multiple marker analysis, cytogenetics, proliferation characteristics, basic clinical findings and the final outcome of the disease in these patients. Beyond that this kind of leukemia research will help to clarify the pathobiological basis of human leukemia and to develop new specific therapeutic modalities.