Human trithorax gene rearrangements in therapy-related acute leukaemia after etoposide treatment.

Molecular analysis of leukaemic blasts from 9 patients with secondary myeloid leukaemia reveals rearrangements of the human trithorax gene (Htrx-1) in three patients, including one in whom abnormalities of chromosome 11 band q23 were not detected by conventional cytogenetics. All three patients had been treated with epipodophyllotoxins, whilst none of the six without rearrangements had received these agents. The patients with rearrangements also presented with different clinical features. These findings support the separation of secondary leukaemia into two classes, and correlate rearrangements of the Htrx-1 gene with a group of secondary leukaemias that follow specific cancer treatment regimens.