SKY reveals a high frequency of unbalanced translocations involving chromosome 6 in t(12;21)-positive acute lymphoblastic leukemia

The G-band cryptic t(12;21)(p13;q22) is the most common chromosomal rearrangement in childhood acute lymphoblastic leukemia (ALL). To investigate the nature of additional chromosomal events in this group of patients spectral karyotyping (SKY) following G-banding analysis was performed in 14 cases. From these cases six showed structural aberrations of chromosome 6, including both simple deletions and unbalanced translocations, and involved both q (n = 4) and p (n = 3) arms. The results show that rearrangements of 6p are also non-random events t(12;21)-positive ALL. This study illustrates the value of a combined SKY and G-banding approach in identifying novel karyotypic events in childhood ALL.