Kourong Miao

Serum microRNAs are promising novel biomarkers for diffuse large B cell lymphoma

MicroRNAs (miRNAs) are regulatory RNA molecules that are deregulated in many disease types, including cancer. Recently, miRNAs have shown promise as markers for cancer diagnosis. The aim of this study was to investigate whether serum miRNAs can be used as biomarkers for the detection of diffuse large B cell lymphoma (DLBCL). We measured the levels of miRNAs (miR-15a, miR-16-1, miR-21, miR-29c, miR-34a, miR-155, and miR-223) in serum samples from patients with DLBCL and healthy controls using real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR). We show here that miRNAs are present in human serum in a remarkably stable form. Four of miRNAs (miR-15a, miR-16-1, miR-29c, and miR-155) were significantly elevated in DLBCL serum when compared with normal controls (P < 0.05), while miR-34a was downregulated in DLBCL serum when compared with controls (P < 0.05). Receiver operating characteristic analyses reflects strong discriminating DLBCL from controls, with area under the curves of 0.7722, 0.7002, 0.6672, 0.8538, and 0.7157 for miR-15a, miR-16-1, miR-29c, miR-34a, and miR-155, respectively. At the cut-off value of 0.0006 for miR-15a, the sensitivity was 80% and the specificity was 76%; at the cut-off value of 0.0886 for miR-16-1, the sensitivity was 94% and the specificity was 51%; at the cut-off value of 1.395 for miR-34a, the sensitivity was 100% and the specificity was 70%; at the cut-off value of 0.0022 for miR-155, the sensitivity was 83% and the specificity was 65%. In conclusion, these data suggest that serum miRNAs are potentially useful tools as novel noninvasive biomarker for the diagnosis of DLBCL.

Downregulated Dicer expression predicts poor prognosis in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the western world. Alterations in microRNAs (miRNAs) expression have been proposed to play a role in CLL pathogenesis. Dicer and Drosha are the main regulators of miRNA biogenesis, and deregulation of their expression has been indicated as a possible cause of miRNA alterations observed in various cancers. To investigate the role of Dicer and Drosha in CLL, we assessed the expression of Dicer and Drosha and their correlation with other prognostic factors, including Binet stages, immunoglobulin heavy chain variable gene (IGHV) mutation status, TP53 mutation status, ZAP‐70 protein and CD38 expression level in 165 CLL patients by using real‐time polymerase chain reaction methods. Patients with unmutated IGHV genes had significantly lower expression of Dicer than patients with IGHV mutations. The lower expression level of Dicer was also significantly associated with higher level of CD38 and ZAP‐70, and more aggressive Binet stage. We also analyzed Dicer expression in different cytogenetic subgroups. Lower Dicer level was found in patients with unfavorable cytogenetic aberrations (deletion in 17p13 or 11q22.3) in contrast to higher level in good risk cytogenetics (deletion in 13q14 as the sole abnormality). Furthermore, the lower expression of Dicer in CLL shows a strong association with shorter overall survival (OS) (P = 0.0046) as well as with reduced treatment free survival (TFS) (P = 0.0006). By contrast, no differences in the expression of Drosha among these groups of patients were observed. Our data suggest that Dicer expression may play an important role in the progression and prognosis of CLL. (Cancer Sci 2012; 103: 875–881)

Co-culture of cord blood CD34+ cells with human BM mesenchymal stromal cells enhances short-term engraftment of cord blood cells in NOD/SCID mice

BACKGROUND The major challenge for cord blood transplantation (CBT) is higher rates of delayed and failed engraftment. In an attempt to broaden the application of CBT to more candidates, ex vivo expansion of hematopoietic stem/progenitor cells in CB is a major area of investigation. The purpose of this study was to employ human BM mesenchymal stromal cells (hBM-MSC) as the feeding-layer to expand CB cells ex vivo. METHODS In this study, hBM-MSC were isolated and characterized by morphologic, mmunophenotypic and RT-PCR analysis. The hBM-MSC at passage 3 were employed as the feeding-layer to expand CB CD34(+) cells in vivo in the presence of thrombopoietin, flt3/flk2 ligand, stem cell factor and G-CSF. The repopulating capacity of the ex vivo-expanded CB cells was also evaluated in a NOD/SCID mice transplant experiment. RESULTS After 1 or 2 weeks of in vitro expansion, hBM-MSC supported more increasing folds of CB in total nucleated cells, CD34(+) cells and colony-forming units (CFU) compared with CB without hBM-MSC. Furthermore, although NOD/SCID mice transplanted with CB cells expanded only in the presence of cytokines showed a higher percentage of human cell engraftment in BM than those with unexpanded CB CD34(+) cells, expanded CB cells co-cultured with hBM-MSC were revealed to enhance short-term engraftment further in recipient mice. DISCUSSION Our study suggests that hBM-MSC enhance in vitro expansion of CB CD34(+) cells and short-term engraftment of expanded CB cells in NOD/SCID mice, which may be valuable in a clinical setting.

The prognostic significance of TP53 mutations in Chinese patients with chronic lymphocytic leukemia is independent of del(17p13)

The poor prognosis of chronic lymphocytic leukemia (CLL) patients with del(17p13) is well established. Several studies have shown that cases with TP53 mutations and TP53 mutations without del(17p13) may be adverse prognostic factors. We studied 173 well-characterized CLL patients by direct sequencing to detect TP53 mutations (exons 2–11). TP53 mutations were detected in 14.5% (25 of 173) of samples. Most patients with del(17p13) had TP53 mutations (72.2%). Mutations in the absence of del(17p13) were found in 8.3% in our cohort, which were higher than other countries. Compared with cases without TP53 alterations, TP53 mutations and deletions were both associated with advanced stages and unmutated immunoglobulin heavy-chain variable region status. Survival analysis showed that the occurrence of TP53 mutations and del(17p13) were associated with shorter overall survival (OS), treatment-free survival (TFS), and resistance to chemotherapy. TP53 mutations were the variables strongly associated with OS and TFS by multivariate Cox regression analysis. Moreover, we also found that cases with TP53 mutations in the absence of del(17p13) had a similar clinical and biological course and similar poor short OS as cases carrying del(17p13) in Chinese patients with CLL.

Aberrant microRNA expression in Chinese patients with chronic lymphocytic leukemia

MicroRNAs (miRNAs) are a class of small endogenous RNAs that play important regulatory roles by targeting mRNAs for cleavage or translational repression. Many reports have indicated that miRNAs play a critical role in malignancies, and regulations in the progression of leukemia. However, the miRNAs expression level in Chinese patients with chronic lymphocytic leukemia (CLL), and its prognostic value remain elusive. We identified various degrees of down-regulation of miR-15a, miR-16-1, miR-29b, miR-181a and miR-181b in CLL mononuclear cells. Moreover, we have identified miR-29b and miR-181a/b expression significantly correlated with IGHV mutational status. Transcript levels of predicted target genes BCL-2 and TCL-1 were also determined, and the expression levels were significantly upregulated in CLL patients compared with normal controls (P<0.001). Higher expression of TCL-1 was significantly correlated with aggressive disease features. In addition, an inverse correlation was observed in the CLL samples we examined between miRNAs (miR-16-1, miR-181a, miR-181b) and BCL-2 level; furthermore, an inverse correlation was also observed between miRNAs (miR-16-1, miR-181a, miR-181b) and TCL-1, which suggest that these miRNAs may implicate in negatively regulating target mRNA at transcriptional level. These different miRNAs may play an important role in the pathogenesis of CLL and might be applied for the assessment of prognosis in patients with CLL.

Serum thymidine kinase 1 concentration in Chinese patients with chronic lymphocytic leukemia and its correlation with other prognostic factors

Chronic lymphocytic leukemia (CLL) shows a remarkable heterogeneity, with some patients having an almost normal lifespan, others surviving only several months after diagnosis despite intensive therapy. The aim of this study was to investigate the serum thymidine kinase 1 (TK1) concentration in Chinese patients with CLL and its correlation with well-established other prognostic factors. Enhanced chemiluminescent dot blot assay was performed to measure serum TK1 concentration in 80 CLL patients. The concentration of TK1 was significantly increased in patients with Binet C (P = 0.002), higher levels of serum lactate dehydrogenase (LDH) (P = 0.012) and β2-microglobulin (β2-MG) (P = 0.025), unmutated IGHV status (P < 0.001), or higher expression levels of ZAP-70 (P = 0.014) and CD38 (P = 0.018) groups compared to the patients with Binet A, lower levels of serum LDH and β2-MG, mutated IGHV status, or lower expression levels of ZAP-70 and CD38 groups, respectively. Strong correlation of TK1 level with IGHV mutations (r = 0.412, P < 0.001) or ZAP-70 (r = 0.263, P = 0.024) was observed. According to receiver operating characteristic curve analysis for serum TK1 concentration and IGHV mutational status, area under the curve was 0.757 (P = 0.001) and the optimal cut-off value of serum TK1 concentration level was 1.75 pM, with a 87.8% specificity, a 63.6% sensitivity. It was showed that serum TK1 concentration could be a predictive marker of IGHV mutational status, and might be applied for the assessment of prognosis in patients with CLL.

Enhancing the action of rituximab by adding fresh frozen plasma for the treatment of fludarabine refractory chronic lymphocytic leukemia.

Complement deficiencies have been identified in many chronic lymphocytic leukemia (CLL) patients. Supplying fresh frozen plasma (FFP)‐derived complement can enhance complement‐dependent cell lysis by the rituximab. The objective of our study was to evaluate the clinical efficacy and safety of the treatment by adding FFP to rituximab in fludarabine refractory CLL patients. Twenty‐two patients were treated with two units of FFP followed with rituximab, 375 mg/m2, as a single agent, repeated every 1–2 weeks. Patients received a median of four courses of the combined FFP and rituximab treatment (range: 2–6). Sixteen patients (72.7%) responded to treatment and seven (31.8%) achieved a complete remission. Three (13.6%) of which had no evidence of minimal residual disease after treatment. Patients with high expression of ZAP‐70 or CD38, unmutated immunoglobulin heavy chain variable region, mutated p53, or adverse cytogenetic features, achieved response to treatment at rates that appeared similar to those who did not have such characteristics. With a median follow‐up of 12 (4–19) months, the median overall survival and progression free survival have not been achieved. Toxicity was minimal, and the treatment was well tolerated. Our data suggest that the adding FFP to rituximab is an effective nonmyelotoxic regimen for the treatment of fludarabine refractory CLL patients.

MDM2 promoter SNP309 is associated with an increased susceptibility to chronic lymphocytic leukemia and correlates with MDM2 mRNA expression in Chinese patients with CLL

A single nucleotide polymorphism (SNP) at position 309 in the promoter region of MDM2 leading to increased expression of MDM2 and attenuated function of p53 has recently been suggested as an unfavorable prognostic marker in chronic lymphocytic leukemia (CLL) although this has been questioned. The MDM2 SNP309 genotypes in 173 CLL patients and 260 healthy controls were detected by the polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method, which was confirmed by direct DNA sequencing. Compared with the T/T genotype, the SNP309 G/G genotype instead of T/G heterozygote was associated with a significantly increased risk of CLL (OR = 2.84; 95% CI 1.61–5.03; p < 0.001). Age at onset of CLL was similar irrespective of MDM2 status. MDM2 mRNA expression within CLL of G/G genotype was significantly higher than that in T/G (p = 0.009) and T/T genotypes (p < 0.001). Excluding patients with p53 deletions or mutations enhanced the significance of the findings (G/G vs. T/T, p < 0.001; G/G vs. T/G p = 0.001), which prompted us to study the role of the polymorphism in p53 wild‐type individuals. In the p53 wild‐type groups, survival analysis showed that the patients with MDM2 SNP309 G/G and T/G genotypes both had significantly shorter treatment‐free survival (TFS) than SNP309 T/T genotype. Notably, univariate and multivariate analyses showed that MDM2 SNP309 genotypes were associated with TFS. These data show that MDM2 309G polymorphisms contribute to the risk of developing CLL. The unfavorable MDM2 SNP309 G/G genotype was associated with an increase of MDM2 mRNA expression. MDM2 SNP309 was found to be associated with TFS in p53 wild‐type Chinese CLL populations.

Intermediate prognosis of 6q deletion in chronic lymphocytic leukemia

Cytogenetic features have an important role in the definition of distinct disease subsets in CLL. The deletion of 6q is known to occur at a relatively low frequency in CLL, and the detailed analysis of hematologic and clinical features of patients with CLL with 6q deletion is limited. To verify the incidence and prognostic significance of 6q deletion in Chinese patients with CLL, fluorescence in situ hybridization (FISH) was used in 240 patients with CLL. del(6q23) was found in 18 patients (7.5%), and only five patients had deletion in 6q23 as the sole abnormality. Strong correlations between del(6q23) and clinical parameters were not found. A difference in terms of survival in patients with del(6q23) as compared with patients without this anomaly was not able to be demonstrated. However, a significant difference was found when comparing the del(6q23) group with the del(17p13) or del(11q22.3) group (p = 0.023), or isolated del(13q14) group (p = 0.019). Our findings place the del(6q23) cytogenetic subset of CLL in an intermediate prognosis position between patients with del(11q22.3) or del(17p13), and patients with isolated del(13q14). FISH probes to detect deletions of 6q might be useful in clinical practice in the work-up of patients with CLL.

The polymorphism and haplotype analysis of HLA-A, -B and -DRB1 genes of population in Jiangsu province of China

The polymorphism of human leucocyte antigen (HLA)‐A, ‐B and ‐DRB1 genes and their computed haplotype analysis results from a population of Jiangsu province of China are presented here. The data consist of 20 248 unrelated peripheral blood stem cell donors in Jiangsu Branch of Chinese National Marrow Donor Program registry. In total, 18 different HLA‐A alleles, 34 different HLA‐B alleles and 13 different HLA‐DRB1 alleles were found in Jiangsu Han population. The most frequent alleles in HLA‐A, ‐B and ‐DRB1 loci were A*02 (29.55%), B*15 (14.40%), and DRB1*09 (16.15%), respectively. The most common haplotype in A‐B‐DRB1 loci was A*30‐B*13‐ DRB1*07 (6.92%), in A‐B loci was A*30‐B*13 (8.05%), in B‐DRB1 loci was B*13‐DRB1*07 (8.17%), and in A‐DRB1 loci was A*02‐DRB1*09 (8.30%). The dendrogram study indicated that the distribution of HLA genes in Jiangsu Han population, as expected, represented a mixture of Northern and Southern Han population in China. These findings could shade new lights in population genetics and anthropology studies of Han‐Chinese.