MOLECULAR HETEROGENEITY IN CHILDHOOD PRECURSOR-B ACUTE LYMPHOBLASTIC-LEUKEMIA WITH IMMUNOGLOBULIN HEAVY-CHAIN GENE IN GERMLINE CONFIGURATION

Four childhood acute leukemias with morphological, cytochemical and im munological characteristics correlating to precursor B lymphocyte and with germline configuration of the immunoglobulin heavy chain joining region were studied for the organization of the C mu segment. Two of t he four lymphoblast samples retained the germline configuration of bot h JH and C mu regions. The other two samples showed delection of the e ntire JH region resulting in the rearrangement of the C mu region. In contrast to patients with C mu rearrangement, patients with C mu in ge rmline form were not able to achieve complete remission after inductio n therapy. Study of the C mu region in patients with JH segment in ger mline configuration could separate subgroups in childhood precursor B acute lymphoblastic leukemia with different prognoses.