Specific chromosomal abnormalities determine the prognostic significance of paediatric acute lymphoblastic leukaemia (ALL) and are used in risk stratification for treatment. Interpretation of chromosomal abnormalities becomes more difficult in the analysis of complex karyotypes and the presence of multiple clones. Interphase fluorescent in situ hybridisation (iFISH) provides an alternative approach, which allows abnormalities to be detected in non-dividing cells. We report the iFISH profile in 91 cases of paediatric ALL in a 5-year 6-month period. IFISH using commercial probes was performed as per the manufacturer’s protocol and included the LSITM TEL/AML1 Dual Colour, Dual Fusion Translocation Probe, LSITM BCR/ABL Dual Colour, Dual Fusion Translocation, LSITM PBX1/TCF3/ABL Dual Colour, Dual Fusion Translocation and the LSITM MLL Dual Colour, Break Apart Rearrangement Probe (Abbott Molecular). Standard descriptive statistics was used to analyse the data. The frequency of non-random structural abnormalities with independent prognostic significance was 53.4 %. The highest observed abnormality was BCR gene amplification (8.2%) followed by TEL gene amplification (6.8%), PBX1 gene amplification (6.8%), TCF3 gene amplification (4.1%) and TCF3 gene deletion (2.7%). TEL gene amplification, TCF3 gene deletion or amplification and PBX1 gene amplification which are rarely reported in paediatric ALL was observed in a significant frequency in our study population. Thus, this could be a unique finding and warrants exploration in a larger patient series.
Murugan et al. (Sun,) studied this question.