The TLX1 product consists of a 179kb probe, labelled in red, located centromeric to the TLX1 gene, including the KAZALD1 gene and the D10S1629 marker and a green probe covering a 124kb region located telomeric to the gene, including the LBX1 gene and the RH92279 marker.
The TLX1 (T-cell leukemia homeobox 1) gene at 10q24 is aberrantly expressed in 30% of adult and 5-10% of childhood T-cell acute lymphoblastic leukaemia (T-ALL)1,2.
Dysregulation of gene transcription is a feature of all acute leukaemias. In T-cell neoplasms, this is brought about by altered expression of normal transcription factor proteins, often as a consequence of chromosomal rearrangements placing these genes into close proximity of the promoter and enhancer elements of the TCR genes: TRA and TRD at 14q11.2, TRB at 7q34 and TRG at 7p143,4.
Murine studies show that expression of mouse homologues of TLX1 can immortalise haematopoietic cells in vitro as the first of a potential two-hit mechanism leading to full malignancy2. This work suggests that TLX1 is an oncogene that can become dysregulated via the translocations t(10;14)(q24;q11) or t(7;10)(q35;q24), placing it into close proximity with TRA/D and TRB elements respectively5. Additionally, TLX1 is frequently activated in T-ALL in the absence of an overt genetic rearrangement. T-ALLs with TLX1 expression show a more favourable outcome than other T-ALLs5.
Running our PETS protocol was taking upwards of 5 hours to complete based on the previous SOP. After the technical training visit from CytoCell, we were able to make some tweaks to reduce the protocol time down to just 1 hour and 15 minutes, with the same or better results.
Assistant Genetic Technologist, Leicestershire Genetics Centre, UK