The DNA index of the leukemic blasts was defined as the ratio of DNA content in leukemic G0/G1 cells to that in normal diploid lymphocytes. A cut-off DNA-index value of 1.16 was used to distinguish prognostic categories.
To date, the only subset of B-lineage ALL cases with a favorable prognosis have been the hyperdiploid group, and DNA index (> 1.16) is currently included as a criteria to identify a subgroup of ALL patients considered for less intense chemotherapy .