Correlation between cyclin A gene expression in adult patients with acute leukemia and drug resistance. 
In order to investigate the relationship between the expression of cyclin A and drug resistance in adult patients with acute leukemia (AL), the mRNA expression of cyclin A, mdr1, Top II alpha, bcl-2 was detected in 64 adult patients with AL and 20 normal controls by semi-reverse transcription polymerase chain reaction (semi-RT-PCR).  It was found that the cyclin A and Top II alpha mRNA expression levels in drug resistant group were significantly lower than in sensitive group (P < 0.01).  Under the same experimental condition no cyclin A mRNA expression was detectable in all normal controls.  The mdr1 and bcl-2 mRNA expression levels in resistant group were significantly higher than in sensitive group (P < 0.01), cyclin A and Top II alpha gene expression levels were closely correlated (rs = +0.794, P = 0.000, n = 64) in all AL patients, but cyclin A was not correlated with mdr1 and bcl-2 gene expression levels.  In drug resistant group there was a negative correlation between the gene expression levels of cyclin A and mdr1 (rs = -0.337, P = 0.029).  The 10 AL patients with positive lower expression of both cyclin A and Top II alpha were all resistant to drugs.  Logistic regression of Binary analysis showed the correlation between the lower expression of cyclin A and drug resistance.  It was concluded that lower expression of cyclin A gene might be an unfavorable prognostic factor for patients with AL, and detection of both cyclin A and Top II alpha gene expression would predict drug resistance in AL patients.