t(7;12)(q36;p13), a new recurrent translocation involving ETV6 in infant leukemia

The ETV6 gene is rearranged as a result of translocations involving a wide variety of chromosomal partners. To date, 12 partner genes for ETV6 have be en cloned, and a further 23 chromosomal regions have been described. We pre viously identified a cryptic t(7; 12) with ETV6 involvement in two cases of infant leukemia. The finding of a third case of t(7; 12), also in an infan t, prompted a more focussed search based on the common features found in th ese patients and those reported in the literature. The selection criteria w ere age at diagnosis < 20 months and the presence of + 19 and/or +8 in the karyotype; cases with abnormalities of 7q and/or 12p were also considered. FISH studies using whole chromosome paints and probes for the ETV6 gene rev ealed a t(7; 12) in 10 out of 23 cases studied. Seven of these had evidence of ETV6 rearrangement. Of those with ETV6 involvement, six had a 7q36 and one a 7q22 breakpoint. Importantly, in three cases the 7q36 breakpoint was within the same PAC, suggesting the existence of a new nonrandom translocat ion. However, in at least one patient the 7q36 breakpoint was different. Th e identification of the 7q partner genes will determine whether it is the d isruption of ETV6 alone, or the formation of fusion genes, that is importan t for leukemogenesis in these patients. As both 7q36 and 7q22 are critical regions of gene loss in del(7q) leukemias, the identification of partner ge nes from these regions may also be important in understanding the pathogene sis of these diseases, (C) 2000 Wiley-Liss, Inc.