Plasma thrombopoietin compared with immunoglobulin heavy-chain mutation status as a predictor of survival in chronic lymphocytic leukemia

In chronic lymphocytic leukemia, activation of the thrombopoietin receptor promotes T-cell inhibitory properties, contributing to immunosuppression

In chronic lymphocytic leukemia (CLL), the immune system is skewed towards a suppressive milieu. Levels of thrombopoietin (TPO), promoting cellular immune regulatory activity in immune thrombocytopenic purpura, were shown to be elevated in CLL patients. This study explored TPO as a potential immunomodulator, supporting CLL progression. We evaluated CLL cell-induced expression of TPO receptor (TPO-R) on T-cells and effects of its activation on T-cell responses. CLL cell involvement in TPO generation was also assessed. Baseline TPO-R expression on CD4 + T-cells was found to be higher in CLL patients than in healthy controls (HC). Exposure of HC-T-cells to B-cells, especially to CLL-B-cells stimulated with B-cell activating molecules, resulted in enhanced TPO-R expression on T-cells. CLL-T-cell stimulation with TPO reduced their proliferation and expanded the regulatory T-cell (Treg) population. At baseline, phosphorylation of STAT5, known to impact the Treg phenotype, was elevated in CLL-T-cells relative to those of HC. Exposure to TPO further enhanced STAT5 phosphorylation in CLL-T-cells, possibly driving the observed Treg expansion. The CLL immune milieu is involved in promotion of inhibitory features in T-cells through increased TPO-R levels and TPO-induced intracellular signaling. TPO and its signaling pathway could potentially support immunosuppression in CLL, and may emerge as novel therapeutic targets.

Is there a role for the platelet-to-lymphocyte ratio in chronic lymphocytic leukemia?

AIM

The rationale for platelet-to-lymphocyte ratio (PLR) in chronic lymphocytic leukemia (CLL) is that both the platelet and lymphocyte counts are affected by the CLL pathogenesis and could influence treatment decision-making.

METHODS

Demographic and clinical data of CLL patients diagnosed at our institution between 1989 and 2013 were collected. Cox regression models were used to evaluate the role of PLR in the duration of watchful waiting, postdiagnosis survival and postchemotherapy survival.

RESULTS

The data of 100 patients with CLL were reviewed for this study. The PLR correlated only to watchful waiting in the univariable analysis (Hazard ratio = 0.48 [0.32-0.73]; p = 0.018). In the multivariable analysis, the duration of watchful waiting was determined by Binet staging and lymphocyte count (p < 0.001). The postdiagnosis survival was determined by age (p = 0.002) and lymphocyte count (p = 0.010).

CONCLUSION

The PLR did not seem to act as a prognostic biomarker for CLL.

Prognostic factors in chronic lymphocytic leukemia-what do we need to know?

Of all leukemias, chronic lymphocytic leukemia (CLL) shows the highest variability in its clinical presentation and course. CLL can present as an aggressive and life threatening leukemia or as an indolent form that will not require treatment over decades. The currently available clinical staging systems for CLL are simple and inexpensive but lack accuracy to predict disease progression and survival on an individual basis. The increased understanding of the key events of molecular pathogenesis has provided a plethora of novel molecular and biological factors that correlate with the outcome of CLL. This Review provides a concise discussion of the most important discoveries and gives guidance on how to implement novel prognostic tools in the clinical management of CLL by applying the criteria of evidence, relevance, and simplicity to the selection of prognostic markers.

Comparison of tumor and microenvironment secretomes in plasma and in platelets during prostate cancer growth in a xenograft model

To survive and metastasize, tumors interact with surrounding tissues by secreting growth factors and cytokines. In return, surrounding host tissues respond by changing their secretome. Numerous factors theoretically function as therapeutic targets or biomarkers of cancer growth and metastatic risk. However, it is unclear if these factors are tumor-derived or actually represent the host defense. To analyze the concentrations of tumor- and microenvironment-derived factors associated with neoplastic growth, we used ELISA-based arrays specific for murine or human proteins to establish a profile of tumor- or host-derived factors circulating in the plasma or within the platelets upon human tumor implantation into mice. Many factors characterized as tumor-derived were actually secreted by host tissues. This study uncovered the origin of various cytokines and revealed their circulation methods. We found that tumor-produced cytokines are predominantly sequestered in platelets. Sequestered proteins are protected from degradation and, thus, may be functional at metastatic sites. These findings identify tumor-specific targets for the detection and prevention of tumor growth and metastasis. As predicted by our model, monocyte chemotactic protein 1 and tumor necrosis factor alpha may be biomarkers for human cancers. Thus, our study identified several potential biomarkers that might be predictive of prostate cancer.

Gene expression meta-analysis identifies chromosomal regions involved in ovarian cancer survival

Ovarian cancer cells exhibit complex karyotypic alterations causing deregulation of numerous genes. Some of these genes are probably causal for cancer formation and local growth, whereas others are causal for metastasis and recurrence. By using publicly available data sets, we have investigated the relation of gene expression and chromosomal position to identify chromosomal regions of importance for early recurrence of ovarian cancer. By use of *Gene Set Enrichment Analysis*, we have ranked chromosomal regions according to their association to survival. Over-representation analysis including 1-4 consecutive cytogenetic bands identified regions with increased expression for chromosome 5q12-14, and a very large region of chromosome 7 with the strongest signal at 7p15-13 among tumors from short-living patients. Reduced gene expression was identified at 4q26-32, 6p12-q15, 9p21-q32, and 11p14-11. We summarized mutation load in these regions by a combined mutation score that is statistical significantly associated to survival by analysis in the data sets used for identification of the regions. Furthermore, the prognostic value of the combined mutation score was validated in an independent large data set using death (P = 0.015) and recurrence (P = 0.002) as outcome. The combined mutation score is strongly associated to upregulation of several growth factor pathways.

Serum beta2-microglobulin measured by immunonephelometry: expression patterns and reference intervals in healthy adults

BACKGROUND

Serum beta2-microglobulin (beta2m) has been established as a marker of disease activity in malignancies, autoimmune conditions and infections. Despite its important role in prognosis assessment and disease monitoring, relatively few studies are available on its expression in healthy individuals. Furthermore, interpretation of results is hampered by the variety in reference limits due to differences in methodology, sample population and statistics.

METHODS

Serum beta2m concentrations were measured using a microparticle-enhanced immunonephelometric method in 183 healthy blood donors aged 29-75 years.

RESULTS

The median beta2m concentration was 1.67 (0.88-2.75) mg/L with no difference between men and women (1.71 mg/L vs. 1.62 mg/L, p<0.07). A linear correlation was found between beta2m and age (p<0.0001), serum concentrations significantly higher in older subjects (1.55, 1.59, 1.70, and 1.87 mg/L in age groups of 29-40, 40-50, 50-60 and 60-75 years, respectively, p<0.0001). Reference intervals obtained by non-parametric estimation after partitioning by age were 1.02-2.46 mg/L vs. 1.29-2.70 mg/L in younger (29-49 years) vs. older (50-75 years) individuals.

CONCLUSIONS

These data can help standardise beta2m reference limits and support age-adjusted comparisons in clinical studies.

Soluble syndecan-1 (sCD138) as a prognostic factor independent of mutation status in patients with chronic lymphocytic leukemia

Syndecan-1 (sCD138) is a transmembrane heparan sulfate-bearing proteoglycan expressed in epithelial cells as well as hematopoietic cells that demonstrate plasmacytoid differentiation. Higher levels of sCD138 correlate with poor outcome in myeloma. We examined the association of circulating sCD138 levels in plasma with clinical behavior in 104 patients with chronic lymphocytic leukemia. sCD138 levels were significantly higher in patients (median, 52.8 ng/ml; range, 13.4-252.7 ng/ml) than in healthy control subjects (median, 19.86; range, 14.49-33.14 ng/ml) (P < 0.01). Elevated sCD138 (>median, 52.8 ng/ml) was associated with significantly shorter survival (P = 0.0004); this association was independent of IgVH mutation status, beta2-microglobulin (beta2-M) level, and treatment history. Patients with mutated IgVH but high sCD138 levels (>52.8 ng/ml) had significantly shorter survival than those with mutated IgVH and lower levels of sCD138. Similarly, patients with unmutated IgVH but high sCD138 levels had significantly shorter survival than those with lower sCD138 levels and unmutated IgVH (P = 0.007). In a multivariate Cox regression model, only Rai stage, beta2-M, and sCD138 remained predictors of survival. These data suggest that sCD138 when combined with beta2-M and Rai stage, may replace the need for testing IgVH mutation status.

Serum thrombopoietin compared with ZAP-70 and immunoglobulin heavy-chain gene mutation status as a predictor of time to first treatment in early chronic lymphocytic leukemia

In an effort to confirm previous reports we analyzed clinico-biological implications of increased serum levels of thrombopoietin (TPO) in a series of 71 previously untreated Binet stage A B-cell chronic lymphocytic leukemia (CLL) patients. Serum levels of TPO did not correlate with peripheral blood lymphocytosis (p = 0.928), Rai substages (p = 0.516), platelet count (p = 0.572), hemoglobin level (p = 0.228), LDH (p = 0.144) and beta2-microglobulin (p = 0.520). The same applied when correlation with ZAP-70 (p = 0.562), CD38 (p = 0.258) or mutational status of IgV(H) (p = 0.0794) were sought. The risk of disease-progression according to known and putative prognostic parameters was also evaluated as time to first treatment (TFT). The univariate Cox proportional hazard model demonstrated that the absence of IgV(H) mutational status (p = 0.0005) and ZAP-70-positivity (p = 0.02) were associated with a shorter TFT. In contrast, Kaplan-Meier estimates of TFT, plotted after setting as cut-off the median value for TPO (i.e., 46 pg/mL), failed to demonstrate any statistical difference between two groups (p = 0.342). Looking for cellular source of TPO we investigated the presence of TPO at gene expression level in 60 B-CLL patients belonging to an independent series. Here we provide evidence for the presence of a low TPO gene expression transcript in B-CLL cells. In conclusion, our results indicate that in early B-cell CLL circulating level of TPO does not provide a useful insight into the complex interrelationship of prognostic variables.

Prognostic markers in chronic lymphocytic leukaemia

Rai and Binet staging of chronic lymphocytic leukaemia (CLL) is being superseded by new prognostic markers. The mutational status of the immunoglobulin variable region heavy-chain genes segregates the disease into more benign and more malignant versions, and has been confirmed as an important prognostic marker in prospective clinical trials. A search for surrogate markers for this difficult-to-perform assay has led to flow cytometric assays for CD38 and ZAP-70 expression, although in both cases there are problems with standardization and interpretation of the assays. A separate pathway of research has revealed two chromosomal aberrations--deletions of 11q and 17p--as important prognostic markers. Fluorescent in-situ hybridization has made their detection readily available. These five markers are in different stages of evaluation, but some of them are ready to be used for risk-adapted therapy in clinical trials. Other assays are in earlier stages of assessment.

New Prognostic Markers in CLL

The individual prognosis of patients with chronic lymphocytic leukemia (CLL) is extremely variable. Although clinical stages remain the basis for assessing prognosis in CLL, a number of biological markers, particularly serum markers, cytogenetic abnormalities, IgVH mutations, CD38 and ZAP-70 expression in leukemic cells offer important, independent prognostic information. Before being incorporated into daily practice, however, these markers require standardization and validation in large, prospective trials. Meanwhile, treatment of patients with CLL not included in clinical studies should be decided on the basis of classical NCI/CLL Working Group criteria. An important area of research in CLL prognostication is the identification of markers useful for predicting response to therapy and its duration. Among them, del(17p), reflecting P53 abnormalities, is particularly important. Also relevant is del(11q), which points to ATM defects. There is also some correlation between IgVH mutational status, ZAP-70 and CD38 expression and response to therapy and its duration, although these relationships need further investigation. Finally, there is increasing evidence that response to therapy, particularly in those cases in which minimal residual disease is eradicated, is associated with longer survival.