CHROMOSOME STUDIES IN A CASE OF BENZENE-INDUCED ERYTHROLEUKAEMIA

Cytogenic studies were carried out in a case of acute erythroleukaemia, which occurred in a patient who had been exposed to benzene. In direct preparations both of peripheral blood and of bone marrow, a stem-line of 46 chromosomes was present, with a pseudodiploid karyotype, due to the absence of 2 chromosomes of group E and to the presence of 2 small markers (a ring chromosome and a minute centric fragment). As the markers were present in all the mitoses observed, most probably belonging both to the erythroid and to the myeloid series, the abnormal chromosome complement seemed to characterize a stem-cell common to both series. The hypothesis is suggested that the exposure to benzene might have induced chromosome breakages and rearrangements in a stem-cell, and that proliferation of such abnormal element might have resulted in the erythroleukaemic clone. © 1969.