N. Hyakuna et al., RETROSPECTIVE ANALYSIS OF CLONALITY AND DETECTION OF RESIDUAL DISEASEIN MYELOID-LEUKEMIA BY FISH ON LONG-TERM STORED BONE-MARROW SMEARS, Acta Paediatrica Japonica Overseas Edition, 40(4), 1998, pp. 318-323
Background: Fluorescence in situ hybridization (FISH) has allowed the
detection of numerical chromosomal aberrations in interphase nuclei on
fresh or frozen smears of leukemia. Methods: To analyze clonality and
residual disease in myeloid leukemia retrospectively we applied FISH
to bone marrow smears stored at ambient temperature for up to 9 years.
Results: When hybridization efficiency was investigated on stored con
trol smears from patients without hematological malignancy, more than
96% of nuclei showed the expected number of signals using DNA probes s
pecific for chromosome 7, X or Y. In combination with cell morphology,
we observed much higher hybridization efficiency in blasts and granul
omonocytic cells compared with lymphoid and erythroid cells. On the ba
sis of good hybridization efficiency for old smear specimens, we appli
ed FISH to stored bone marrow smears of myeloid leukemias, in which ei
ther loss of chromosome 7 or loss of sex chromosomes had been verified
previously by conventional cytogenetics (one patient with chronic mye
lomonocytic leukemia (CMML) and four with acute myeloid leukemia (AML;
three M2 and one M7)). As a result, the loss of chromosome was detect
ed in blasts from all patients and was observed in mature granulocytes
, except in M7. In the CMML patient and one AML (M2) patient with t(8;
21), lymphoid and erythroid cells also showed the loss of chromosomes,
suggesting that it should occur at stem-cell level. A high amount of
residual disease was detected in the morphological remission samples i
n one AML (M2) patient after induction therapy. The patient eventually
succumbed to relapse. Conclusion: Thus, the present FISH technique is
useful to analyze the clinical significance of clonality and the resi
dual disease in myeloid leukemia, retrospectively.