P53 PROTEIN DETECTED BY 2 DIFFERENT ANTIBODIES - RELATIONSHIP TO PROLIFERATION AND PROGNOSIS IN ACUTE LYMPHOBLASTIC-LEUKEMIA

The expression, of p53 protein was examined in a series of 69 children with acute lymphoblastic leukemia with two different monoclonal antib odies (Mab 1801 and 240). p53 expression was detected with at least on e antibody in 49 cases (71%), whereas only 19 cases (27%) were positiv e with both antibodies. Variability in the immunostaining could be obs erved depending on the antibody used. Mab 240 gave the highest rate of positive staining (58%), followed by 1801 with 39%. Positive staining with 1801 was significantly associated with decreased proliferation o f tumor cells as measured by Ki-67 labelling, indicating that possibly the wild-type p53 protein is preferably stained with this antibody. H owever, neither of the two antibodies has prognostic value or is corre lated with histopathological parameters.