title: Plasma leptin and leptin receptor expression in childhood acute lymphoblastic leukemia.
abstract: Recently, leptin has been shown to play a regulatory role for differentiation within the myeloid and erythroid cell lineage, whereas results of its regulatory effects on lymphocytes and related tumor cells have been contradictory. To investigate whether leptin plays a role in acute lymphoblastic leukemia (ALL), we investigated the levels of leptin in plasma with enzyme-linked immunosorbent assays and the expression of the leptin receptor on malignant lymphoblasts with reverse transcriptase polymerase chain reaction (RT-PCR). At diagnosis, the leptin levels of bone marrow-derived plasma in children with ALL were found to be significantly lower than the levels of healthy control subjects (0.92 +/- 0.79 ng/mL versus 3.01 +/- 2.27 ng/mL, respectively). Notably, at complete hematologic remission (at day 33 of chemotherapy), leptin levels had normalized to 2.6 +/- 2.4 ng/mL. To elucidate the underlying mechanism of this phenomenon, we analyzed the expression of the leptin receptor on the mononuclear cell populations of the patients. RT-PCR analysis revealed gene expression rates of 33% at diagnosis versus 71% at remission, compared with 100% for healthy control subjects. Results of immunohistochemical staining supported these findings by showing that the tumor clones themselves do not express the leptin receptor. Finally, some hypotheses that might explain the decrease of leptin levels in the presence of the tumor clone are discussed.
authors.affiliation: Department of Paediatric Haematology and Oncology, Otto-von-Guericke-University, Magdeburg, Germany. heike.wex@medizin.uni-magdeburg.de
authors.forename: Heike
authors.initials: H
authors.lastname: Wex
authors.forename: Edita
authors.initials: E
authors.lastname: Ponelis
authors.forename: Thomas
authors.initials: T
authors.lastname: Wex
authors.forename: Regina
authors.initials: R
authors.lastname: Dressendörfer
authors.forename: Uwe
authors.initials: U
authors.lastname: Mittler
authors.forename: Peter
authors.initials: P
authors.lastname: Vorwerk
mesh_terms: D000293:Adolescent; D000328:Adult; D001853:Bone Marrow / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D020738:Leptin / Q000097:blood*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D054411:Receptors, Leptin
chemical_list: C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin