Altered expression of p53 and mdm-2 proteins at diagnosis is associated with early treatment failure in childhood acute lymphoblastic leukemia.
OBJECTIVE
To determine whether potential alteration in p53 function through p53 gene mutation or mdm-2 overexpression correlates with early treatment failure in childhood acute lymphoblastic leukemia (ALL).


METHODS
Diagnostic marrow samples from 34 children were analyzed for p53 gene alterations by western blot and SSCP/DNA sequence analysis and for mdm-2 overexpression by western blot analysis. These samples were derived from two groups of children with ALL: 17 good outcome patients who are in long-term continuous complete remission and 17 poor outcome patients who did not achieve a complete remission or relapsed within 6 months of achieving remission.


RESULTS
Two children within the poor outcome group were found to have p53 gene mutations. Furthermore, five poor outcome patients were shown to have greater than 10-fold overexpression of mdm-2 protein compared with the mean level of mdm-2 protein measured in the good outcome group. Aberrant p53 protein expression was found in only one good outcome patient, whereas no good outcome children were found to have elevated levels (> 10-fold) of mdm-2 protein.


CONCLUSIONS
We show for the first time that potential alteration in p53 function in childhood ALL is more common (P = .036) in cases of early treatment failure than in children who remain in long-term continuous remission.
Marks
D I
DI
Department of Medicine, Allegheny University of the Health Sciences, Philadelphia, PA 19102, USA.
Kurz
B W
BW
Link
M P
MP
Ng
E
E
Shuster
J J
JJ
Lauer
S J
SJ
Carroll
D
D
Brodsky
I
I
Haines
D S
DS
D002648:Child; D002675:Child, Preschool; D016158:Genes, p53 / Q000235:genetics; D006801:Humans; D009154:Mutation; D009687:Nuclear Proteins; D010865:Pilot Projects; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2; D017211:Treatment Failure; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2