ABSTRACT
This study was aimed to investigate the expression level of puma (p53 up-regulated modulator of apoptosis) mRNA in chronic lymphocytic leukemia (CLL) and its significance in evaluation of CLL prognosis. The puma mRNA expressions in 100 CLL patients and 11 normal controls were measured by relative quantification RT-PCR with fluorescent dye SYBR Green I, the beta-actin was used as internal reference. The difference of puma expression rate between groups with different prognostic factors was described using the Mann-Whitney U test. The relative quantitative value of puma expression was calculated by means of 2 (-ΔCt). The results indicated that the correlation coefficients of the standard curves in qRT-PCR were ≥ 0.99. The coefficients of variations (CV) within group or between groups were < 5%, and the sensitivity reached 10² copies/microg RNA. The median puma mRNA expression level was 1.038 x 10⁻³ (4.106 x 10⁻⁴ - 2.806 x 10⁻³) in CLL patients, which was 1.220 x 10⁻³ (7.233 x 10⁻⁴ - 1.405 x 10⁻³) in normal controls. There was no difference of puma mRNA expression between CLL patients and normal controls (U = 544.5, p = 0.957). Puma expression was significantly correlated with Binet stages (p < 0.001), expression of CD38 (p = 0.002), ZAP-70 protein (p = 0.012), LDH levels (p = 0.009) and beta₂-MG (p = 0.046). The puma expression level in patients with earlier Binet stage (Binet stage A) was obviously higher than that in patients with later Binet stage (Binet stage B, C). The puma expression levels in patients with positive expression of CD38 and ZAP-70 protein, elevating levels of LDH and beta₂-MG were sharply lower than those in patients without above-mentioned unfavorable factors. The puma expression was also correlated with molecular cytogenetic abnormalities, the puma expression levels in patients with trisomy 12 (p = 0.003) and 14q32 translocation (p = 0.045) detected by FISH were significantly lower than those in patients without above-mentioned molecular cytogenetic abnormalities. It is concluded that the qRT-PCR assay is reliable and sensitive. Puma mRNA expression is significantly correlated with a great deal of prognostic factors, and may be a prognostic marker of CLL.