PO-63 - Exhausted platelets in cancer patients with high risk of venous thromboembolism and poor prognosis

Platelet dysfunction and thrombus instability in flow conditions in patients with severe COVID-19

Severe COVID-19 has been associated with a high rate of thrombotic events but also of bleeding events, particularly when the level of prophylactic anticoagulation was increased. Data on the contribution of platelets to these thrombotic events are discordant between reports, while the involvement of platelets in bleeding events has never been investigated. The objective of the present study was to assess platelet function during the first week of ICU hospitalization in patients with severe COVID-19 pneumonia. A total of 35 patients were prospectively included and blood samples were drawn on day (D) 0, D2 and D7. COVID-19 pneumonia was severe with a median PaO₂/FiO₂ ratio of 91 [68-119] on D0. Platelets from these patients showed evidence of pre-activation and exhaustion with a significant reduction in the surface expression of GPVI, GPIb and GPIIbIIIa, together with a decrease in serotonin content. Platelets from patients with severe COVID-19 were hyporesponsive with a reduced maximal aggregation response to several platelet agonists and decreased adhesion to immobilized fibrinogen. Aggregation of washed platelets and plasma substitution experiments indicated that a plasma factor was at least partially responsible for this hyporeactivity of platelets. Blood flow experiments showed that severe COVID-19 platelets formed smaller, less stable aggregates on a collagen-coated surface, which could explain why some patients develop bleeding events. These findings should prompt us to carefully evaluate the risks and benefits of high-dose prophylactic anticoagulation, and to decrease the level of anticoagulation once the initial phase of the disease has resolved. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04359992.

Prognostic significance of mean platelet volume in patients with lung cancer: a meta-analysis

OBJECTIVE

The mean platelet volume (MPV) is a measure of platelet size, and it is considered a surrogate marker of platelet activation. Because the correlation between platelet count/size and lung cancer prognosis remains unclear, this meta-analysis comprehensively evaluated the prognostic significance of MPV among patients with lung cancer.

METHODS

A systematic search of PubMed, Embase, Google Scholar, and additional sources of relevant studies were conducted with no language restrictions from inception to 7 May 2021. Overall survival (OS) and disease-free survival (DFS)/progression-free survival (PFS), as well as their hazard ratios (HR) and 95% confidence intervals (CIs), were pooled to evaluate the relationship between MPV and survival. The study protocol was registered on PROSPERO.

RESULTS

Eleven studies involving 2421 patients with lung cancer were included in our analysis. Nine studies including only patients with non-small cell lung cancer were included in the meta-analysis. Our analysis revealed no significant associations of MPV with OS (HR = 1.09, 95% CI = 0.84-1.41) and DFS/PFS (HR = 1.13, 95% CI = 0.58-2.20).

CONCLUSION

Pretreatment MPV levels did not display prognostic significance in patients with NSCLC. Large-scale prospective studies and a validation study considering ethnicity and lung cancer staging are warranted.

The decreased mean platelet volume is associated with poor prognosis in patients with oropharyngeal cancer treated with radiotherapy

Background

There is considerable evidence that platelets contribute to cancer growth and metastatic dissemination. In recent studies, altered mean platelet volume (MPV) has been associated with prognosis in different types of cancer. However, the prognostic role of the MPV in head and neck squamous cell cancer (HNSCC) is currently discussed controversially. The present study was performed to analyze and further elucidate the prognostic significance of the MPV in HNSCC.

Methods

A total of 319 oropharyngeal squamous cell cancer (OPSCC) patients treated with radiotherapy at a tertiary academic center were enrolled in the present study. Kaplan–Meier method as well as uni- and multivariate Cox proportional hazards were used to evaluate the impact of MPV on cancer-specific survival (CSS), locoregional control (LC) and recurrence-free survival (RFS).

Results

The median MPV was 10.30 fL (mean 10.26 ± 1.17fL). Univariate analyses showed a significant association of the MPV with CSS (HR 0.85, 95% CI 0.74–0.98, p = 0.025), LC (HR 0.86, 95% CI 0.74–0.99, p = 0.034) and RFS (HR 0.87, 95% CI 0.76–0.996; p = 0.043). In multivariate analysis, the MPV remained an independent prognostic factor for CSS (HR 0.77, 95% CI 0.63–0.93, p = 0.008), LC (HR 0.80, 95% CI 0.65–0.98, p = 0.030), and RFS (HR 0.83, 95% CI 0.685–0.999, p = 0.049).

Conclusions

Our findings indicate that the MPV is a prognostic marker in OPSCC patients and may contribute to future individual risk assessment.

The "Janus Face" of Platelets in Cancer

Besides their vital role in hemostasis and thrombosis, platelets are also recognized to be involved in cancer, where they play an unexpected central role: They actively influence cancer cell behavior, but, on the other hand, platelet physiology and phenotype are impacted by tumor cells. The existence of this platelet-cancer loop is supported by a large number of experimental and human studies reporting an association between alterations in platelet number and functions and cancer, often in a way dependent on patient, cancer type and treatment. Herein, we shall report on an update on platelet-cancer relationships, with a particular emphasis on how platelets might exert either a protective or a deleterious action in all steps of cancer progression. To this end, we will describe the impact of (i) platelet count, (ii) bioactive molecules secreted upon platelet activation, and (iii) microvesicle-derived miRNAs on cancer behavior. Potential explanations of conflicting results are also reported: Both intrinsic (heterogeneity in platelet-derived bioactive molecules with either inhibitory or stimulatory properties; features of cancer cell types, such as aggressiveness and/or tumour stage) and extrinsic (heterogeneous characteristics of cancer patients, study design and sample preparation) factors, together with other confounding elements, contribute to “the Janus face” of platelets in cancer. Given the difficulty to establish the univocal role of platelets in a tumor, a better understanding of their exact contribution is warranted, in order to identify an efficient therapeutic strategy for cancer management, as well as for better prevention, screening and risk assessment protocols.

Signaling pathway network alterations in human ovarian cancers identified with quantitative mitochondrial proteomics

RELEVANCE

Molecular network changes are the hallmark of the pathogenesis of ovarian cancers (OCs). Network-based biomarkers benefit for the effective treatment of OC.

PURPOSE

This study sought to identify key pathway-network alterations and network-based biomarkers for clarification of molecular mechanisms and treatment of OCs.

METHODS

Ingenuity Pathway Analysis (IPA) platform was used to mine signaling pathway networks with 1198 human tissue mitochondrial differentially expressed proteins (mtDEPs) and compared those pathway network changes between OCs and controls. The mtDEPs in important cancer-related pathway systems were further validated with qRT-PCR and Western blot in OC cell models. Moreover, integrative analysis of mtDEPs and Cancer Genome Atlas (TCGA) data from 419 patients was used to identify hub molecules with molecular complex detection method. Hub molecule-based survival analysis and multiple multivariate regression analysis were used to identify survival-related hub molecules and hub molecule signature model.

RESULTS

Pathway network analysis revealed 25 statistically significant networks, 192 canonical pathways, and 5 significant molecular/cellular function models. A total of 52 canonical pathways were activated or inhibited in cancer pathogenesis, including antigen presentation, mitochondrial dysfunction, GP6 signaling, EIF2 signaling, and glutathione-mediated detoxification. Of them, mtDEPs (TPM1, CALR, GSTP1, LYN, AKAP12, and CPT2) in those canonical pathway and molecular/cellular models were validated in OC cell models at the mRNA and protein levels. Moreover, 102 hub molecules were identified, and they were regulated by post-translational modifications and functioned in multiple biological processes. Of them, 62 hub molecules were individually significantly related to OC survival risk. Furthermore, multivariate regression analysis of 102 hub molecules identified significant seven hub molecule signature models (HIST1H2BK, ALB, RRAS2, HIBCH, EIF3E, RPS20, and RPL23A) to assess OC survival risks.

CONCLUSION

These findings provided the overall signaling pathway network profiling of human OCs; offered scientific data to discover pathway network-based cancer biomarkers for diagnosis, prognosis, and treatment of OCs; and clarify accurate molecular mechanisms and therapeutic targets. These findings benefit for the discovery of effective and reliable biomarkers based on pathway networks for OC predictive and personalized medicine.

Critical evaluation of platelet size as a prognostic biomarker in colorectal cancer across multiple treatment settings: a retrospective cohort study

PURPOSE

The role of mean platelet volume (MPV) as a predictor of outcomes in various cancer entities including colorectal cancer (CRC) has already been analyzed. However, data on the prognostic and predictive value of MPV in CRC over multiple lines of systemic therapy are missing.

METHODS

In this retrospective single-center cohort study, 690 patients with UICC stage II, III or IV CRC receiving adjuvant and/or palliative chemotherapy were included. Primary endpoints in the adjuvant, palliative and best supportive care (BSC) setting were 3-year recurrence-free survival (RFS), 6-months progression-free survival (PFS), and 6-months overall survival (OS), respectively. Kaplan-Meier estimators, log-rank tests, and uni- and multivariable Cox models were used to analyze RFS, PFS and OS. A cut-off defining patients with low MPV was chosen empirically at the 25th percentile of the MPV distribution in the respective treatment setting.

RESULTS

Three-year RFS was 76%. Median 6-month PFS estimates in 1st, 2nd and 3rd line therapy were 59, 37 and 27%, respectively. Median 6-month OS in BSC was 31%. Small platelets as indicated by low MPV did not predict for shorter RFS. In the first 3 palliative treatment lines a consistent association between low MPV and decreased 6-month PFS was not observed. In the BSC setting, patients with low MPV had numerically but not significantly shorter OS. Higher MPV levels did not consistently predict for ORR or DCR across the first 3 palliative treatment lines.

CONCLUSION

Small platelets are not predicting CRC outcomes, and thus are hardly useful for influencing clinical decision making.

Longer procoagulant phospholipid-dependent clotting time, lower endogenous thrombin potential and higher tissue factor pathway inhibitor concentrations are associated with increased VTE occurrence in patients with newly diagnosed multiple myeloma: results of the prospective ROADMAP-MM-CAT study

Venous thromboembolism (VTE) is a common complication in newly diagnosed symptomatic multiple myeloma (NDMM) patients. We explored cellular and plasma hypercoagulability in NDMM patients to identify relevant biomarkers that can be used in combination with clinical factors in the development of a risk assessment model (RAM) for VTE. Untreated patients (n = 144) with NDMM were prospectively enrolled, baseline biomarkers prior to anti-myeloma treatment and thromboprophylaxis initiation were obtained. These were compared against values in a group of healthy individuals with similar age and sex distribution. The primary study end point was symptomatic VTE occurrence. At 12-month follow-up cumulative VTE rate was 10.4%. NDMM patients showed biological signs of cellular and plasma hypercoagulability and endothelial cell activation. Procoagulant phospholipid clotting time (Procoagulant-PPL) was shorter, P-selectin levels lower and thrombin generation attenuated overall compared to healthy subjects. Longer Procoag-PPL^®, lower endogenous thrombin potential (ETP), and higher levels of tissue factor pathway inhibitor (TFPI) were associated with VTE occurrence. Multivariate analysis showed that Procoag-PPL^® and ETP were independent risk factors for VTE. We conclude that Procoag-PPL^® and ETP can be prospectively incorporated into a RAM for VTE in MM in combination with clinical and disease risk factors.

Protease-activated receptor-1 (PAR-1): a promising molecular target for cancer

PAR-1 is expressed not only in epithelium, neurons, astrocytes, immune cells, but also in cancer-associated fibroblasts, ECs (epithelial cells), myocytes of blood vessels, mast cells, and macrophages in tumor microenvironment, whereas PAR-1 stimulates macrophages to synthesize and secrete thrombin as well as other growth factors, resulting in enhanced cell proliferation, tumor growth and metastasis. Therefore, considerable effort has been devoted to the development of inhibitors targeting PAR-1. Here, we provide a comprehensive review of PAR-1’s role in cancer invasiveness and dissemination, as well as potential therapeutic strategies targeting PAR-1 signaling.