[Expression of MOST-1 mRNA in bone marrow mononuclear cells from patients with acute lymphoblastic leukemia].

OBJECTIVE

To investigate the MOST-1 mRNA expression in bone marrow (BM) mononuclear cells in children with acute lymphoblastic leukemia, and to explore its association with immunophenotype and treatment response.

METHODS

Semiquantitative RT-PCR was employed to study the MOST-1 mRNA expression in BM mononuclear cells separated by Ficoll density gradient method. The MOST-1 expression levels were represented by the ratio of MOST-1 band pixels against its corresponding housekeeping gene beta-actin mRNA band pixels determined by GDS8000 densitometry and GelWork-1 analysis software. The PCR product was eluted and sequenced, and its sequence was confirmed by Pairwise BLAST search.

RESULTS

A total of 17 children with acute lymphoblastic leukemia were studied. MOST-1 mRNA was exclusively expressed in the mononuclear cells from 3 patients with ALL-L3 type. However, there was no MOST-1 mRNA expression in other 14 children with ALL-L1 or ALL-L2, irrespective of their initial peripheral WBC count and blast cell percentage in peripheral blood and bone marrow. The MOST-1 mRNA expression levels in two of the ALL-L3 patients with higher blast cell percentages in peripheral blood and bone marrow were 3- and 2-fold respectively as compared with that in the third ALL-L3 child with lower initial blast cell load. MOST-1 mRNA expression was no longer detected in the two ALL-L3 children after complete remission with combination chemotherapy.

CONCLUSION

MOST-1 was expressed in the bone marrow mononuclear cells in patients with ALL-L3, and its expression level was somewhat related to tumor cell burden. It might be implicated in the leukemogenesis of ALL-L3 and might serve as an indicator of tumor burden and thus a useful guide for clinical management.