Determination of clonality in acute nonlymphocytic leukemia by restriction fragment length polymorphism and methylation analysis.

Determination of cellular clonality in hematological malignancies provides fundamental information that is important in understanding the pathogenesis of these disorders. We present here an extension of one approach to accomplish this that is based on the interpretation of different methylation patterns on active and inactive X chromosomes within the region of the hypoxanthine-guanine phosphoribosyltransferase gene spanned by a restriction fragment length polymorphism. The successful application of the method to determine clonality is described for three female patients with acute nonlymphocytic leukemia.