Flow cytometry using
a DNA label can quantitate
aneuploid clones in malignant tissue. We illustrated the clinical value of this technique in a 71-year-old woman with
acute megakaryocytic leukemia, which was diagnosed by staining of the blasts with
factor VIII antigen and their morphologic resemblance to megakaryoblasts. Marrow cells were removed from needle biopsies by vortexing in RPMI medium, centrifuged in
Ficoll-
Hypaque, stained with a
propidium-iodide/NP-40 mixture, and analyzed at 488 nm using an
argon laser. During 3 weeks of low-dose
cytosine arabinoside (
ara-c) infusion
therapy, hyperdiploid peak A dropped from 35% (day 0) to 2.3% (day 14) to 0% (day 21), with development of marrow hypoplasia. Similarly, hyperdiploid peak B, went from 7.6% to 9.1% to 3.5%. Subsequently, her marrow recovered normal morphology and lost the
aneuploid peaks. Her blood counts recovered to near normal. Four months later, she relapsed and had a return of the day-21, incompletely eradicated peak B. There was no evidence of peak A. Repeated treatment with
ara-c resulted in temporary suppression of the disease, but she died 3 months later with progressive hepatosplenomegaly. Analysis of cells from her
enlarged liver, heavily infiltrated with blasts, showed a large hyperdiploid peak B. In this patient,
ara-c therapy induced a remission with permanent eradication of one clone, but incomplete eradication of a second clone, which ultimately led to her relapse and death.