Does thrombopoiesis in multiple myeloma patients depend on the stage of the disease?

Association of Thrombocytopenia With Disease Burden, High-Risk Cytogenetics, and Survival in Newly Diagnosed Multiple Myeloma Patients Treated With Novel Therapies

BACKGROUND

The effect of thrombocytopenia has not been studied in the era of novel treatments in multiple myeloma (MM).

OBJECTIVE

To evaluate the clinical characteristics and outcomes in MM patients presenting with thrombocytopenia.

MATERIALS

Newly diagnosed MM patients between 2008 and 2018 who received at least 2 novel agents at induction. Thrombocytopenia was defined as a platelet count of less than < 150,000/mm3.

RESULTS

A total of 648 patients were identified. Thrombocytopenia was found in 120 patients (18.5%). Baseline disease characteristics associated with higher rates of thrombocytopenia at baseline included IgA myeloma, P < .01, ISS 3 versus 1 or 2, P < .01, R-ISS 3 versus 1 or 2, P < .01, renal failure (CrCl < 30 mL/min), P < .01, hypercalcemia (Ca > 11.5 mg/dL), P < .01, elevated LDH, P < .03, anemia (Hb < 10 g/dL), P < .01, higher serum monoclonal protein, P < .02, and > 60% plasma cells in the bone marrow, P < .01. Thrombocytopenia was more prevalent across patients with t(4;14) and t(14;16), but was not associated with an overall high-risk fluorescence in situ hybridization (FISH) classification. Median OS was significantly lower among patients with thrombocytopenia (64.4 vs. 145.0 months, P < .01). In multivariable Cox regression, thrombocytopenia was associated with mortality (HR = 2.45, 95% CI, 1.7-3.6) independently of age, sex, high-risk FISH, ISS stage, response at induction, percentage of plasma cells in the BM, and anemia.

CONCLUSION

We found that thrombocytopenia was seen among one-fifth of MM patients and was more common in patients with (t[4; 14] and t[14; 16]). Thrombocytopenia had an independent association with worse survival.

Thrombopoietin Promotes Angiogenesis and Disease Progression in Patients with Multiple Myeloma

Multiple myeloma (MM) progression closely depends on bone marrow (BM) angiogenesis. Several factors sustain angiogenesis, including cytokines, growth factors, and cell-to-cell interactions. Herein, BM thrombopoietin (TPO) was shown to support angiogenesis and disease progression in MM. Patients with MM at different progression phases had higher levels of BM and circulating TPO than monoclonal gammopathy of undetermined significance/smoldering MM patients, suggesting that TPO correlates with disease progression and prognosis. Endothelial cells from patients with monoclonal gammopathy of undetermined significance (MGECs) and endothelial cells from MM (MMECs) expressed TPO receptor, and the TPO treatment triggered their angiogenic capabilities in vitro. Indeed, TPO-treated MGECs and MMECs showed enhanced angiogenesis on Matrigel and spontaneous cell migration and chemotaxis by acting as a chemotactic agent. TPO also had an angiogenic activity in vivo in the chorioallantoic membrane assay system. Finally, TPO treatment increased the release of active matrix metalloproteinase (MMP)-9 and MMP-2 in MGECs and of MMP-2 in MMECs and affected the balance between angiogenic/antiangiogenic factors in the MM BM. Our results support the angiogenic activity of TPO, and suggest that it may have a critical role in promoting the angiogenic switch during MM progression. Accordingly, TPO may be envisaged as a new angiogenic and prognostic factor in patients with MM.

Polymorphisms in the promoter region of the CRBN gene as a predictive factor for the first-line CTD therapy in multiple myeloma patients

Cereblon is a primary molecular target for immunomodulatory drugs. The aim of this study was to evaluate the influence of selected clinical and molecular factors including single nucleotide polymorphisms (SNPs) in CRBN gene on the efficacy of first line CTD (cyclophosphamide, thalidomide, dexamethasone) chemotherapy in patients with multiple myeloma. Study group consisted of 68 patients. Analysis of CRBN gene SNPs (rs6768972, rs1672753) was performed using Real-Time PCR genotyping technique. Median progression free survival (PFS) was 15 months and overall survival (OS) 79 months. Factors associated with significantly shorter OS included ISS 3, kidney disease, weight loss, anemia, thrombocytopenia, hypoalbuminemia, elevated β2-microglobuline and CRP. The presence of t(4;14) was associated with significantly shorter PFS and OS. Both examined SNPs proved to be statistically significant, independent predictive factors of efficacy of the CTD chemotherapy. The presence of AA genotype (rs6768972) correlated with longer median PFS (18 vs 9 months; HR=0.49,95% CI: 0.26-0.91, p=0.0062). Conversely, in the carriers of CC genotype (rs1672753) significantly shorter median PFS was observed (4 vs 16 months; HR=3.93, 95% CI: 0.26-59.64, p=0.0321). In conclusion, SNPs of the CRBN gene may be useful in qualifying patients for treatment with regimens containing thalidomide.

Platelet RNA signatures for the detection of cancer

Platelets are equipped with RNA processing machineries, such as pre-mRNA splicing, pre-miRNA processing, and mRNA translation. Since platelets are devoid of a nucleus, most RNA transcripts in platelets are derived from megakaryocytes during thrombocytogenesis. However, platelets can also ingest RNA molecules during circulation and/or interaction with other cell types. Since platelets were first described by Bizzozero in 1881, their well-established role in hemostasis and thrombosis has been intensively studied. However, in the past decades, the list of biological processes in which platelets play an important role keeps expanding. In this review, we discuss how platelet RNA biomarker signatures can be altered in the presence of cancer.

Platelet RNA as a circulating biomarker trove for cancer diagnostics

Platelets are multifunctional cell fragments, circulating in blood in high abundance. Platelets assist in thrombus formation, sensing of pathogens entering the blood stream, signaling to immune cells, releasing vascular remodeling factors, and, negatively, enhancing cancer metastasis. Platelets are 'educated' by their environment, including in patients with cancer. Cancer cells appear to initiate intraplatelet signaling, resulting in splicing of platelet pre-mRNAs, and enhance secretion of cytokines. Platelets can induce leukocyte and endothelial cell modeling factors, for example, through adenine nucleotides (ATP), thereby facilitating extravasation of cancer cells. Besides releasing factors, platelets can also sequester RNAs and proteins released by cancer cells. Thus, platelets actively respond to queues from local and systemic conditions, thereby altering their transcriptome and molecular content. Platelets contain a rich repertoire of RNA species, including mRNAs, small non-coding RNAs and circular RNAs; although studies regarding the functionality of the various platelet RNA species require more attention. Recent advances in high-throughput characterization of platelet mRNAs revealed 10 to > 1000 altered mRNAs in platelets in the presence of disease. Hence, platelet RNA appears to be dynamically affected by pathological conditions, thus possibly providing opportunities to use platelet RNA as diagnostic, prognostic, predictive, or monitoring biomarkers. In this review, we cover the literature regarding the platelet RNA families, processing of platelet RNAs, and the potential application of platelet RNA as disease biomarkers.