RECURRENT CYTOGENETIC ABNORMALITIES OBSERVED IN COMPLETE REMISSION OFACUTE MYELOID-LEUKEMIA DO NOT NECESSARILY MARK PRELEUKEMIC CELLS

We have undertaken the cytogenetic monitoring of 39 adult patients tre ated for de novo acute myeloid leukemia (AML) by intensive chemotherap y. We describe this monitoring in seven patients in continuous complet e clinical and morphologic remission (CR) of AML. Although in CR, thes e patients exhibit the emergence of cytogenetically abnormal clones. A bnormalities observed include monosomy 7, del(20)(q11), partial trisom y Iq, and 6p12-22 rearrangements. They correspond to well-known chromo somal rearrangements commonly found in myelodysplasia (MDS), and myelo proliferative syndromes (MPS), as well as AML. Present as the sole det ected chromosomal change, they preceded by months the onset of overt l eukemia or MDS. In some cases, the abnormal clone showed a proliferati ve advantage (some patients exhibited up to 100% of abnormal bone marr ow metaphases in subsequent analyses). AML relapse, when it occurred, was associated with a different chromosomal modification. Altogether t he question arises, whether the abnormalities pointed out in our study (monosomy 7, del(20)(q11), partial trisomy for the long arm of chromo some 1 (q2lqter), 6p12-22 rearrangements), and seen after chemotherapy , mark preleukemic cells or not, and whether they participate indirect ly, or not at all in the leukemic process.