CHROMOSOME-ABNORMALITIES OF THE SHORT ARM OF CHROMOSOME-12 IN HEMATOPOIETIC MALIGNANCIES - A REPORT INCLUDING 3 NOVEL TRANSLOCATIONS INVOLVING THE TEL ETV6 GENE/

A wide variety of abnormalities of the short arm of chromosome 12 has been reported in hematologic malignancies. The most frequent rearrange ments result from t(12;21)(p13;q22) of childhood acute lymphoblastic l eukemia, a translocation cryptic when leukemic cells are analyzed with chromosome banding techniques. This translocation results in a fusion of the TEL/ETV6 and AML1 genes, in this report, examples of rearrange ments of 12p are presented. Study of two complex chromosome abnormalit ies associated with t(12;21) emphasizes the importance of using FISH i n detection of such translocations. Three novel translocations involvi ng the TEL/ETV6 gene localized an 12p13 are also reported: t(X;12)(q28 ;p13), t(1;12)(q21;p13), and t(9;12)(p23-24;p13). Finally, the present ation of two translocations with breakpoints located centromeric to TE L/ETV6 highlights the not uncommon involvement of genes other than TEL /ETV6 on 12p.