Prognostic factors in chronic lymphocytic leukemia

lncRNA profiling in early-stage chronic lymphocytic leukemia identifies transcriptional fingerprints with relevance in clinical outcome

Long non-coding RNAs (lncRNAs) represent a novel class of functional RNA molecules with an important emerging role in cancer. To elucidate their potential pathogenetic role in chronic lymphocytic leukemia (CLL), a biologically and clinically heterogeneous neoplasia, we investigated lncRNAs expression in a prospective series of 217 early-stage Binet A CLL patients and 26 different subpopulations of normal B-cells, through a custom annotation pipeline of microarray data. Our study identified a 24-lncRNA-signature specifically deregulated in CLL compared with the normal B-cell counterpart. Importantly, this classifier was validated on an independent data set of CLL samples. Belonging to the lncRNA signature characterizing distinct molecular CLL subgroups, we identified lncRNAs recurrently associated with adverse prognostic markers, such as unmutated IGHV status, CD38 expression, 11q and 17p deletions, and NOTCH1 mutations. In addition, correlation analyses predicted a putative lncRNAs interplay with genes and miRNAs expression. Finally, we generated a 2-lncRNA independent risk model, based on lnc-IRF2-3 and lnc-KIAA1755-4 expression, able to distinguish three different prognostic groups in our series of early-stage patients. Overall, our study provides an important resource for future studies on the functions of lncRNAs in CLL, and contributes to the discovery of novel molecular markers with clinical relevance associated with the disease.

Circulating microRNA as Biomarkers in Hematological Malignancies

Hematopoiesis is a highly regulated process controlled by a complex network of molecular mechanisms that simultaneously regulate differentiation, proliferation, and apoptosis of hematopoietic stem cells. Aberrant microRNA (miRNA) expression could affect normal hematopoiesis, leading to the development of hematological malignancies. Hematologic cancers, which are caused by malignant transformation of cells of the bone marrow and the lymphatic system, are usually divided into three major groups: leukemias, lymphomas, and monoclonal gammopathies. Hematologic malignancies are highly aggressive diseases with high morbidity and mortality. For these reasons, early and easily obtainable markers for diagnosis, risk stratification, and follow-up are essential for improvement of outcome and survival of these patients. Recent studies have provided new insights about the diagnostic value of expression patterns of miRNAs in serum/plasma in these diseases. While the use of circulating miRNAs is only at the experimental level, it appears to have a great potential. This chapter deals with the use of circulating miRNAs as minimally invasive biomarkers in hematologic malignancies.

Prognostic information and biological insights in chronic lymphocytic leukemia by high-resolution immunophenotypic analysis of ZAP70

The E2997 Phase III trial included preservation of valuable chronic lymphocytic leukemia (CLL) patient specimens and relevant clinical outcome data. Using a novel high-resolution technology on a flow cytometry platform, we assessed 79 E2997 samples for the expression of 27 analytes that reflected the activity of signaling pathways and apoptosis. We found that the expression levels of ZAP70 segregated the samples into two subpopulations with the distribution showing a peak-trough-peak configuration. Although prior assessment of ZAP70 by standard procedures did not reveal any prognostic information, we found by using the trough in the distribution as a cutpoint that ZAP70 expression levels were significantly correlated with both progression-free survival and overall survival. Additionally, the cells expressing high versus low levels of ZAP70 demonstrated distinct molecular organization as indicated by the other analytes assessed. Our analysis demonstrates the value of ZAP70 expression as a prognostic indicator and suggests that the different clinical results may be due to the distinct molecular biology of the ZAP70-low versus the ZAP70-high CLL samples.

Small nucleolar RNAs as new biomarkers in chronic lymphocytic leukemia

BACKGROUND

Small nucleolar RNAs (snoRNAs) and small Cajal body-specific RNAs are non-coding RNAs involved in the maturation of other RNA molecules. Alterations of sno/scaRNA expression may play a role in cancerogenesis. This study elucidates the patterns of sno/scaRNA expression in 211 chronic lymphocytic leukemia (CLL) patients (Binet stage A) also in comparison with those of different normal B-cell subsets.

METHODS

The patterns of sno/scaRNA expression in highly purified CD19+ B-cells of 211 CLL patients and in 18 normal B-cell samples--6 from peripheral blood, and 12 from tonsils (4 germinal center, 2 marginal zone, 3 switched memory and 3 naïve B-cells)--were analyzed on the Affymetrix GeneChip® Human Gene 1.0 ST array.

RESULTS

CLLs display a sno/scaRNAs expression profile similar to normal memory, naïve and marginal-zone B-cells, with the exception of a few down-regulated transcripts (SNORA31, -6, -62, and -71C). Our analyses also suggest some heterogeneity in the pattern of sno/scaRNAs expression which is apparently unrelated to the major biological (ZAP-70 and CD38), molecular (IGHV mutation) and cytogenetic markers. Moreover, we found that SNORA70F was significantly down-regulated in poor prognostic subgroups and this phenomenon was associated with the down-regulation of its host gene COBLL1. Finally, we generated an independent model based on SNORA74A and SNORD116-18 expression, which appears to distinguish two different prognostic CLL groups.

CONCLUSIONS

These data extend the view of sno/scaRNAs deregulation in cancer and may contribute to discover novel biomarkers associated with the disease and potentially useful to predict the clinical outcome of early stage CLL patients.

A network meta-analysis of therapies for previously untreated chronic lymphocytic leukemia

BACKGROUND

Several therapy options are available for symptomatic, treatment-naïve chronic lymphocytic leukemia (CLL). Many of these therapies have been compared against chlorambucil, but have not been directly compared against each other. There is currently no agreed upon standard therapeutic regimen for treatment-naïve CLL.

METHODS

We performed a systematic literature review to identify randomized controlled trials (RCTs) published prior to November 2011 of therapies for previously untreated CLL. We conducted a network meta-analysis using fixed and random effect statistical models to estimate differences between shape and scale parameters of progression-free survival (PFS) curves for each competing therapy. We used the parameter estimates and a Weibull distribution to project mean PFS for each therapy option.

RESULTS

Five RCTs were included in our comparison network. Overall, patients were younger (59-65 years), had good performance status based on the Eastern Cooperative Oncology Group scale (ECOG 0-1), and earlier stage disease (Rai 0-II or Binet A or B). The combination regimen fludarabine with cyclophosphamide and rituximab (FCR) was estimated to yield mean PFS of 76 months (95% CrI: 60, 91), FC 60 months (46, 73), fludarabine 38 months (27, 49), alemtuzumab 24 months (15, 32), and chlorambucil 23 months (15, 32).

CONCLUSION

Our results suggest that FCR has relatively higher potential of preventing disease progression in younger, healthier, treatment-naïve CLL patients and should be considered an optimal initial treatment strategy for this patient population. However, because estimates are based on model simulation, additional studies of FCR are necessary to clinically validate its therapeutic potential.

Plasma proteome analysis in HTLV-1-associated myelopathy/tropical spastic paraparesis

Background

Human T lymphotropic virus Type 1 (HTLV-1) causes a chronic inflammatory disease of the central nervous system known as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM) which resembles chronic spinal forms of multiple sclerosis (MS). The pathogenesis of HAM remains uncertain. To aid in the differential diagnosis of HAM and to identify pathogenetic mechanisms, we analysed the plasma proteome in asymptomatic HTLV-1 carriers (ACs), patients with HAM, uninfected controls, and patients with MS. We used surface-enhanced laser desorption-ionization (SELDI) mass spectrometry to analyse the plasma proteome in 68 HTLV-1-infected individuals (in two non-overlapping sets, each comprising 17 patients with HAM and 17 ACs), 16 uninfected controls, and 11 patients with secondary progressive MS. Candidate biomarkers were identified by tandem Q-TOF mass spectrometry.

Results

The concentrations of three plasma proteins - high [β2-microglobulin], high [Calgranulin B], and low [apolipoprotein A2] - were specifically associated with HAM, independently of proviral load. The plasma [β2-microglobulin] was positively correlated with disease severity.

Conclusions

The results indicate that monocytes are activated by contact with activated endothelium in HAM. Using β2-microglobulin and Calgranulin B alone we derive a diagnostic algorithm that correctly classified the disease status (presence or absence of HAM) in 81% of HTLV-1-infected subjects in the cohort.

MicroRNA as biomarkers and regulators in B-cell chronic lymphocytic leukemia

Early cancer detection and disease stratification or classification are critical to successful treatment. Accessible, reliable, and informative cancer biomarkers can be medically valuable and can provide some relevant insights into cancer biology. Recent studies have suggested improvements in detecting malignancies by the use of specific extracellular microRNAs (miRNAs) in plasma. In chronic lymphocytic leukemia (CLL), an incurable hematologic disorder, sensitive, early, and noninvasive diagnosis and better disease classification would be very useful for more effective therapies. We show here that circulating miRNAs can be sensitive biomarkers for CLL, because certain extracellular miRNAs are present in CLL patient plasma at levels significantly different from healthy controls and from patients affected by other hematologic malignancies. The levels of several of these circulating miRNAs also displayed significant differences between zeta-associated protein 70 (ZAP-70)(+) and ZAP-70(-) CLL. We also determined that the level of circulating miR-20a correlates reliably with diagnosis-to-treatment time. Network analysis of our data, suggests a regulatory network associated with BCL2 and ZAP-70 expression in CLL. This hypothesis suggests the possibility of using the levels of specific miRNAs in plasma to detect CLL and to determine the ZAP-70 status.