ESTABLISHMENT OF A NOVEL HUMAN MYELOID-LEUKEMIA CELL-LINE (HNT-34) WITH T(3-3)(Q21-Q26), T(9-22)(Q34-Q11) AND THE EXPRESSION OF EVI1 GENE, P210 AND P190 BCR ABL CHIMERIC TRANSCRIPTS FROM A PATIENT WITH AML AFTER MDS WITH 3Q21Q26 SYNDROME/

A novel human myeloid leukaemia cell line (HNT-34) was established fro m the peripheral blood of a 45-year-old female patient with acute myel ogenous leukaemia (AML) transformed from chronic myelomonocytic leukae mia (CMMoL) with 3q21q26 syndrome. Morphologically, the HNT-34 cells w ere undifferentiated blasts which were negative for myeloperoxidase. T he HNT-34 cells were positive for CD4, CD13, CD33 and CD34, but negati ve for CD41a and CD42b. The cells actively proliferated in suspension with a doubling time of 26-27 h in the absence of any growth factors. Neither proliferative advantage nor differentiation was observed with the addition of G-CSF GM-CSE IL-3, TPO, DMSO or PMA. Cytogenetic analy sis showed 46,XX, t(3;3)(q21;q26), t(9;22)(q34:q11),20q-, Molecular an alysis showed expression of EVI1 gene, P210 and P190 BCR/ABL chimaeric transcripts. The chromosomal breakpoint at 3q26 of HNT-34 cell line w as located to approximately 200 kb 5' of FIM3 locus and more upstream of the MDS1, which is the same region as that of somatic cell hybrid l ine H10C. The breakpoint at 3q21 was located within the 390kb centrome ric from the breakpoint cluster region. These results suggest that the HNT-34 cell line may be a useful tool for the elucidation of the mech anisms of leukaemogenesis which involve the 3q21q26 syndrome and Ph-1 chromosome.