OBJECTIVETo investigate the clinical significance of cyclin B1 expression in adult acute leukemia (AL) patients.

METHODSThe expression of cyclin B1 and p21 and their cell cycle distribution were measured by flow cytometry in 85 adult patients with de novo AL, 10 continuous complete remission (CCR) AL and 17 normal controls (NC). The mRNAs of cyclin B1, p21 cip1 and proliferation cell nuclear antigen (PCNA) in patients and NCs were measured with semi-quantity reverse transcription polymerase chain reaction (RT-PCR).

RESULTSCyclin B1 protein expression in de novo AL patients was significantly higher than that in NC (P < 0.001). It was higher in relapsed patients than in NC (P < 0.05) but was lower than in de novo AL (P < 0.01). There was no difference between the remission cases and NC (P = 0.21), and between CCR patients and NC (P > 0.05). The cyclin B1 overexpression ratio was higher than that of NC. A negative correlation between the expression levels of cyclin B1 and P21 was observed (r = -0.266, P < 0.05). The cyclin B1 protein expression level was positively correlated with its mRNA level. The expression of cyclin B1 was positively correlated with proliferation index (PI) levels, and with PCNA levels (rPI = 0.7314, rPCNA = 0.7152). Remission rate was higher in high cyclin B1 expression patients than in normal cyclin B1 expression patients (P < 0.01), so did the relapse rate (P < 0.01). Patients with higher cyclin B1 expression had higher survival rate.

CONCLUSIONCyclin B1 was overexpressed and abnormally distributed in cell cycle phases in de novo AL patients. Overexpression of cyclin B1 might be a favorable prognostic factor for patients with AL.