Detection of balanced translocations in acute lymphoblastic leukemia by a novel multiplex reverse transcriptase reverse transcription-polymerase chain reaction.

Fusion transcripts detection is essential for subtyping and diagnosis of acute lymphoblastic leukemia (ALL). This enables institution of appropriate therapy and provides a parameter to monitor disease progression and response to therapy. This study endeared to detect and analyze various balanced translocations known in ALL by using a novel polymerase chain reaction (PCR) method. A pilot study was done in which 16 consecutive cases of ALL were analyzed and followed-up for a period of 1 year. Diagnosis of ALL was established after subjecting blood/bone marrow aspirate samples to morphological examination, immunophenotyping, and detection of fusion transcripts by multiplex reverse transcription (RT)-PCR using HemaVision kit. Results were analyzed by correlating with morphology, immunophenotype, and response to therapy. Epi-Info statistical software was used. 43% (seven cases) showed balanced translocations, with all seven cases being B-ALL and t(9;22) being the most common. There was a consistent association of CD25 cases with t(9;22). Analyses of relation to other parameters were as expected by their respective WHO 2008 subtype. No significant correlation in terms of survival benefit was seen between cases with and without balanced translocations (P = 0.7472). The study demonstrated the utility of multiplex RT-PCR in the initial evaluation, subtyping, and monitoring minimal residual disease in ALL cases with balanced translocations, thereby guiding both therapy and prognosis. The consistent association of CD25 in cases of t(9;22) ALL indicated that CD25 could be used as a surrogate marker.