Cytogenetic characteristics of a murine in vitro model for the human anaplastic large cell lymphoma (ALCL)

Anaplastic large cell lymphoma (ALCL) is an entity of non-Hodgkin lymphomas (NHL) that often occurs in young children and adolescents. In the majority of cases, ALCL are of T-cell origin and contain the t(2;5)(p23;q35) leading to an NPM-ALK fusion or variant ALK translocations. In addition, there is an ALK-negative subtype of ALCL. The anaplastic lymphoid cell line TS1G6 established by interleukin (IL)-9 transfection of T-helper cells represents a murine model of this subtype. Here, we describe the cytogenetic features of this cell line using spectral karyotyping (SKY) and single-color fluorescence in situ hybridization (FISH). We show that TS1G6 cells exhibit a hypotetraploid karyotype with complex structural alterations. Several unbalanced translocations involved the chromosomal region 14E5, and different translocation partners, i.e. X?A6, 3A3 and 8A1. FISH analysis using a BAC clone containing c-myc confirmed the presence of six copies, but also demonstrated that two loci were irregularly located, indicating that additional intrachromosomal rearrangements had occurred. Moreover, a duplication of the region XF2 approximately 3 was identified. Furthermore, six chromosomes 15 were found, representing a trisomy 15 in a tetraploid chromosome complement, indicating an altered gene dosage of the oncogene c-myc located in region 15D3.