VARIANT T(821) REARRANGEMENTS IN ACUTE MYELOBLASTIC-LEUKEMIA OF CHILDHOOD

In a collaborative cytogenetic analysis of blast cells from 638 childr en with acute myeloid leukemia, 74(11.6%) of the patients had the typi cal t(8;21) (q22;q22), while seven (1.1%) had complex variant transloc ations also involving 8q22 and 21q22 as well as a variable chromosome. In each case with a complex rearrangement, the myeloid leukemic cells contained Auer rods and were classified as M2 in the French-American- British (FAB) system. These seven children had a median age of 14 year s (range, 7.3-18.9 years), a median initial leukocyte count of 9.1 x 1 0(9)/L (range, 2.5-142.2 x 10(9)/L), and have survived leukemia free f or a median of 23 months (1-41 months) after attaining complete remiss ion. The variable chromosomes in these seven cases -1, 2, 7, 12, 13, 1 5, and 17- appeared to be randomly involved. The clinico-biologic feat ures of our cases with a variant t(8;21) are consistent with those of the published cases with the standard t(8;21), and support the hypothe sis that the critical genetic alteration produced by the t(8;21) is lo cated on the derivative 8.