Frequency of MLL Gene Rearrangement AF4 t(4;11) in Adult Acute Lymphoblastic Leukemia - A Single Institute Experience - Abstract
Background: Mixed lineage leukemia (MLL) is one of the most frequently involved genes in hematologic malignancies, in particular in some forms of acute leukemia, both lymphoblastic and myeloid. In adult ALL, MLL gene re-arrangement is found in 7% cases as reported in previous studies. MLL gene rearrangement is associated with poor prognosis. MLL gene rearrangements arise from fusions of this gene at 11q23 with a large number of partner genes. In ALL, the most common gene partner is the AF4 gene on chromosome 4q21 resulting in a t(4; 11) (q21; q23) rearrangement.
Objective/Rationale: This study was planned to estimate the frequency of MLL gene rearrangement AF4 t(4;11) in patients of acute lymphoblastic leukemia because this rearrangement is associated with unfavorable prognosis.
Material and methods: It was a cross-sectional observational study. All newly diagnosed cases of adult ALL were included in the study. Total 101 patients were included, 88 had B-cell lineage ALL and 13 had T-Cell lineage ALL. Institutional review board approved the study. Informed consent was obtained and
details were noted in a Performa including age, gender, clinical features, complete blood count (CBC), and bone marrow aspirate and biopsy report. Diagnosis was done on the basis of WHO classification of neoplasm 2008. RT- PCR method was applied to detect MLL gene rearrangement AF4 t(4;11).
Results: Out of 101 patients, 34 were females and 67 males, with mean age of 34.5 ± 18.9 (range 18-50 years in both females & males). MLL gene rearrangement AF4 t(4;11) was detected in 08(7.9%) patients of ALL. The mutation was observed in 03(37.5%) males out of 67 and 05(14.7%) females out
of 34. Significantly more MLL gene rearrangement was found in patients with pre-B-Cell ALL (75%), then in pre-T-Cell ALL (25%).
Conclusion: MLL gene rearrangement AF4 t(4;11) has been detected in 7.9% cases of ALL in our study. Further larger studies are needed to validate our data and follow up required for elucidation of clinical significance of mutation in this group of patients.