S. Hernandez et al., cdc25A and the splicing variant cdc25B2, but not cdc25B1, -B3 or -C, are over-expressed in aggressive human non-Hodgkin's lymphomas, INT J CANC, 89(2), 2000, pp. 148-152
cdc25 is a Family of phosphatases that activate the cyclin-dependent kinase
s at different points of the cell cycle. cdc25A and -B, but not -C, have be
en shown to have oncogenic potential, Three different splicing variants of
the cdc25B gene, cdc25B1, -B2 and -B3, have also been identified. Experimen
tal studies suggest that cdc25B2 may be more active in vivo than cdc25B3 an
d -B1, but the relative expression of these splicing variants in human tumo
rs is not. known. In this study, we have analyzed the expression of cdc25A,
-B1, -B2, -B3 and -C mRNA in 9 non-neoplastic lymphoid samples, 89 non-Hod
gkin's lymphomas and 9 hematological cancer cell lines by semi-quantitative
RT-PCR, cdc25A, -B and -C protein expression was examined by Western blot.
Normal peripheral blood lymphocytes and reactive tissues expressed cdc25B1
and -B3 mRNA and very low or undetectable levels of cdc25A, -B2 and -C, Hi
gh levels of cdc25A and cdc25B2 were found in 35% and 39% of the tumors, re
spectively, and they were more frequently observed in aggressive than in in
dolent lymphomas, cdc25B1 and -B3 splice variants were detected in virtuall
y all tumors, and no significant differences were found between high- and l
ow-grade lymphomas, cdc25A and -B protein expression was also higher in agg
ressive than in indolent lymphomas, cdc25C expression was relatively low in
virtually all cases. In conclusion, these findings suggest that cdc25A and
-B2, but not cdc25B1, -B3 and -C, are over-expressed in a relatively large
number of malignant lymphomas and may participate in the pathogenesis of a
ggressive variants. (C) 2000 Wiley-Liss, Inc.