Rare cytogenetic abnormalities and their clinical relevance in pediatric acute leukemia of Saudi Arabian population

BACKGROUND: Childhood Acute Leukemia (AL) is characterized by recurrent genetic aberrations in 60% of AML cases and 90% of ALL cases. Insufficient data exists of rare cytogenetic abnormalities in AL. Therefore, we tested rare cytogenetic abnormalities occurring in childhood AL and its effect on clinical prognosis in patients diagnosed at our institution from 2010 to 2017. RESULTS: Among 150 cases of AL, we detected 9 cases with rare chromosomal abnormalities. We found two hypodiploid (2n-) cases: 2n-,t (5;14)(q31;q32) and t (3;11;19)(q21;q23;q13.1) in ALL patients. AML patients showed t (7;14)(q22;q32), t (11;17)(p15;q21), t (11;20) (p15;q11), t (12;17)(q15;q23) and t (11;20)(p15;q11). Both t (1;15)(q10;q10) and t (17;19)(q21;p13.3) occurred in a case with biphenotypic AL. Complete remission (CR) status was attained in 3 patients and 6 patients never attained CR or relapsed/demised. CONCLUSION: The study highlighted that rare cytogenetic abnormalities are associated with a poor prognosis. This finding is not well reported in the literature suggesting that ongoing cytogenetic studies for rare abnormalities associated with pediatric leukaemia are warranted.