LMO2 (LIM domain only 2) is expressed in a subset of acute myeloid leukaemia and correlates with normal karyotype

AimLMO2 is a transcription factor that plays a key role in haematopoiesis. Expression of LMO2 has been demonstrated in germinal centre B cells, various B cell lymphomas and T lymphoblastic lymphoma/leukaemia (T-ALL), but has not been studied extensively in acute myeloid leukaemia (AML). MethodsWe studied LMO2 expression by immunohistochemistry in biopsies from a cohort of AML patients (n=196) and correlated it with established prognostic factors such as age, bone marrow morphology and cytogenetic findings. ResultsForty per cent (79 of 196) of the samples from AML patients showed moderate/strong expression of LMO2 protein. LMO2 expression showed a significant positive correlation with normal cytogenetics (65% versus 24%, P<0.0001) and a moderately negative correlation with complex karyotype [r(s)(98)=-0.218, P<0.002]. AML associated with core binding factor [(t(8;21)/inv(16)/t(16;16)] had low LMO2 expression compared to diploid karyotype (29% versus 65%; P=0.013). Expression of LMO2 protein exhibited an insignificant association with age (P=0.197). Lower expression of LMO2 protein was noted in AML associated with myelodysplasia-related changes, compared to AML subtypes based on FAB classification (M0-M7) (21% versus 44%, P=0.0187). ConclusionsLMO2 is expressed in a subset of AML patients and is associated with normal karyotype, which is different from T-ALL, where specific translocation (11p13) mediates protein expression.