[Expression of lactoferrin and myeloperoxidase genes in blasts of acute lymphoblastic leukemia]

The myeloperoxidase (MPO) and lactoferrin genes are strictly associated to the granulocytic differentiation pathway. Many reports show that immunologic and molecular cell markers, though to be lineage specific, are in fact expressed in cells of different lineages. We have identified lymphoid blast cell populations expressing the MPO gene at the mRNA level, but lacking any detectable MPO protein. We addressed this issue studying the expression of the MPO and lactoferrin genes in extremely homogeneous Acute Lymphoblastic Leukemia (ALL) blast cell populations. The study was carried out by solution hybridization of total cellular mRNA extracted from the leukemic populations with an antisense RNA transcribed by riboprobes. Either MPO or lactoferrin mRNAs were detectable in some ALL populations.