The wolf in sheep's clothing: Platelet-derived "pseudo self" impairs cancer cell "missing self" recognition by NK cells

Determinants of Metastatic Colorectal Cancer With Permanent Liver- Limited Disease

Colorectal cancer (CRC) is a complex and genetically heterogeneous disease presenting a specific metastatic pattern, with the liver being the most common site of metastasis. Around 20%-25% of patients with CRC will develop exclusively hepatic metastatic disease throughout their disease history. With its specific characteristics and therapeutic options, liver-limited disease (LLD) should be considered as a specific entity. The identification of these patients is particularly relevant in view of the growing interest in liver transplantation in selected patients with advanced CRC. Identifying why some patients will develop only LLD remains a challenge, mainly because of a lack of a systemic understanding of this complex and interlinked phenomenon given that cancer has traditionally been investigated according to distinct physiological compartments. Recently, multidisciplinary efforts and new diagnostic tools have made it possible to study some of these complex issues in greater depth and may help identify targets and specific treatment strategies to benefit these patients. In this review we analyze the underlying biology and available tools to help clinicians better understand this increasingly common and specific disease.

The role of platelets in the regulation of tumor growth and metastasis: the mechanisms and targeted therapy

Platelets are a class of pluripotent cells that, in addition to hemostasis and maintaining vascular endothelial integrity, are also involved in tumor growth and distant metastasis. The tumor microenvironment is a complex and comprehensive system composed of tumor cells and their surrounding immune and inflammatory cells, tumor-related fibroblasts, nearby interstitial tissues, microvessels, and various cytokines and chemokines. As an important member of the tumor microenvironment, platelets can promote tumor invasion and metastasis through various mechanisms. Understanding the role of platelets in tumor metastasis is important for diagnosing the risk of metastasis and prolonging survival. In this study, we more fully elucidate the underlying mechanisms by which platelets promote tumor growth and metastasis by modulating processes, such as immune escape, angiogenesis, tumor cell homing, and tumor cell exudation, and further summarize the effects of platelet-tumor cell interactions in the tumor microenvironment and possible tumor treatment strategies based on platelet studies. Our summary will more comprehensively and clearly demonstrate the role of platelets in tumor metastasis, so as to help clinical judgment of the potential risk of metastasis in cancer patients, with a view to improving the prognosis of patients.

Harnessing NK Cells to Control Metastasis

In recent years, tumor immunotherapy has produced remarkable results in tumor treatment. Nevertheless, its effects are severely limited in patients with low or absent pre-existing T cell immunity. Accordingly, metastasis remains the major cause of tumor-associated death. On the other hand, natural killer (NK) cells have the unique ability to recognize and rapidly act against tumor cells and surveil tumor cell dissemination. The role of NK cells in metastasis prevention is undisputable as an increase in the number of these cells mostly leads to a favorable prognosis. Hence, it is reasonable to consider that successful metastasis involves evasion of NK-cell-mediated immunosurveillance. Therefore, harnessing NK cells to control metastasis is promising. Circulating tumor cells (CTCs) are the seeds for distant metastasis, and the number of CTCs detected in the blood of patients with tumor is associated with a worse prognosis, whereas NK cells can eliminate highly motile CTCs especially in the blood. Here, we review the role of NK cells during metastasis, particularly the specific interactions of NK cells with CTCs, which may provide essential clues on how to harness the power of NK cells against tumor metastasis. As a result, a new way to prevent or treat metastatic tumor may be developed.

A double-edged sword with a therapeutic target: iron and ferroptosis in immune regulation

Cellular activities such as DNA synthesis, adenosine triphosphate production, and mitochondrial respiration are affected by iron metabolism. Disturbance of iron homeostasis usually leads to damage in cells and organs in the context of iron overload or deficiency. Thus, iron, a key regulator in nutritional immunity, was shown to be critical in innate and adaptive immunity. Unlike apoptosis, ferroptosis, a feature of iron-dependent lipid peroxidation, is thought to be associated with immune regulation because of its immunogenic nature. In this review, we summarize the role of iron and ferroptosis in immune regulation and discuss their therapeutic potential in the treatment of arthropathies like osteoarthritis and rheumatoid arthritis.

The PARP Enzyme Family and the Hallmarks of Cancer Part 2: Hallmarks Related to Cancer Host Interactions

Poly (ADP-ribose) polymerases (PARPs) modify target proteins with a single ADP-ribose unit or with a poly (ADP-ribose) (PAR) polymer. PARP inhibitors (PARPis) recently became clinically available for the treatment of BRCA1/2 deficient tumors via the synthetic lethality paradigm. This personalized treatment primarily targets DNA damage-responsive PARPs (PARP1-3). However, the biological roles of PARP family member enzymes are broad; therefore, the effects of PARPis should be viewed in a much wider context, which includes complex effects on all known hallmarks of cancer. In the companion paper (part 1) to this review, we presented the fundamental roles of PARPs in intrinsic cancer cell hallmarks, such as uncontrolled proliferation, evasion of growth suppressors, cell death resistance, genome instability, replicative immortality, and reprogrammed metabolism. In the second part of this review, we present evidence linking PARPs to cancer-associated inflammation, anti-cancer immune response, invasion, and metastasis. A comprehensive overview of the roles of PARPs can facilitate the identification of novel cancer treatment opportunities and barriers limiting the efficacy of PARPi compounds.

Association of preoperative systemic Immune-inflammation Index and Prognostic Nutritional Index with survival in patients with Upper Tract Urothelial Carcinoma

Background: Both systemic inflammation response and malnutrition are closely related to poor prognosis in patients with certain types of solid tumor. This study investigated the prognostic value of the preoperative combination of systemic immune-inflammation index and prognostic nutritional index (SII-PNI) in patients with upper tract urothelial carcinoma (UTUC) undergoing radical nephroureterectomy (RNU). Methods: The predictive ability of SII-PNI was developed and further validated in a cohort of 525 UTUC patients (253 in the training cohort and 272 in the validation cohort) who received RNU. Results: Survival analysis indicated that a SII ≥672.44 was significantly associated with worse overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS) while a PNI ≥47.83 was associated with better survival outcomes (All P-values < 0.05). The combination of simultaneously SII ≥672.44 and PNI <47.83 was a powerful independent risk factor for OS, CSS, and RFS (P < 0.05). The SII-PNI had the largest area under the curve (AUC) compared to that for SII or PNI alone and other clinical factors, indicating its superior for predicting survival. In addition, the incorporation of the SII-PNI into established nomograms or current clinical parameters such as pathologic T stage and N stage, achieved higher c-indexes or larger AUC than without, indicating that adding SII-PNI helped predict prognosis. All results were found in the training cohort and confirmed in the validation cohort. Conclusions: SII-PNI was a strong independent predictor of UTUC patients after RNU.

Prognostic significance of systemic immune-inflammation index in patients with intrahepatic cholangiocarcinoma undergoing hepatic resection

BACKGROUND

The prognosis of intrahepatic cholangiocarcinoma (ICC) patients following surgical resection remains poor. It is necessary to investigate effective biomarkers or prognostic models for ICC patients.

AIM

To investigate the prognostic effect of systemic immune-inflammation index (SII) to predict long-term outcomes in ICC patients with undergoing hepatic resection.

METHODS

Consecutive ICC patients who underwent initial hepatectomy with curative intent from January 2009 to September 2017 were retrospectively reviewed. Receiver-operating characteristic (ROC) curves were used to determine the optimal cut-off values of SII. Kaplan-Meier curves and Cox proportional hazards regression were performed to evaluate the discriminative ability of preoperative SII in predicting overall survival (OS) and recurrence-free survival (RFS).

RESULTS

A total of 530 patients were included and randomly divided into derivation (n = 265) and validation cohort (n = 265). The optimal cut-off value for SII was 450. At a median follow-up of 18 mo (range, 1-115.4 mo), 317 (59.8%) patients died and 381 (71.9%) patients experienced tumor relapse. Low SII level was associated with better OS and RFS (both P < 0.05). Multivariate analyses identified multiple tumors, node invasion and high SII level as independent risk factors for OS, while multiple tumors, node invasion and high SII level were identified as independent risk factors for RFS. Validation cohort confirmed the findings of derivation cohort.

CONCLUSION

The present study demonstrated the feasibility of preoperative SII as a prognostic indicator for ICC. Patients with increased SII level were associated with worse OS and earlier tumor recurrence. Elevated SII level was an independent risk factor for OS and RFS in patients with ICC after hepatectomy. In the future, the SII could help stratifying patients with ICC, thus guiding therapeutic choices, especially in immunotherapy.

Combination of Platelet-Lymphocyte Ratio and Monocyte-Lymphocyte Ratio as a New Promising Prognostic Factor in Upper Tract Urothelial Carcinoma With Large Tumor Sizes > 3 cm

PURPOSE

The purpose of this study was to evaluate the prognostic values of pathological tumor size and preoperative blood-based inflammation biomarkers, including the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and monocyte-lymphocyte ratio (MLR), in upper tract urothelial carcinoma (UTUC).

MATERIALS AND METHODS

From 2007 to 2017, retrospective data of 449 patients with UTUC who underwent radical nephroureterectomy were assessed. Use of Kaplan-Meier and univariable/multivariable analyses evaluated the effect of preoperative blood-based inflammation biomarkers on overall (OS), cancer-specific (CSS), and progression-free survival (PFS) in pathological tumor sizes > and ≤3 cm.

RESULTS

Kaplan-Meier analyses showed that high-level NLR, PLR, or MLR had significantly shorter OS, CSS, and PFS for tumor sizes >3 cm (all P < .05), but not for ≤3 cm. For UTUCs with tumor sizes >3 cm, multivariable analyses showed simultaneously high-level PLR and MLR to be independent predicators of poor OS, CSS, and PFS (all P < .05). Moreover, receiver operating characteristic (ROC) analyses revealed that the predictive accuracy of the combination of PLR and MLR for OS, CSS, and PFS with the area under the ROC curve of 0.836, 0.871, and 0.806, respectively, in tumor sizes >3 cm (all P < .001).

CONCLUSIONS

Our study demonstrated that a high-level PLR and MLR can serve as an independent predicator of worse outcomes in UTUCs with tumor sizes >3 cm. This combination can clinically help enhance the prognostic discrimination of UTUCs with tumor sizes >3 cm and further may guide physicians in selecting patients for postoperatively systemic chemotherapy.

Combination of Systemic Inflammation Response Index and Platelet-to-Lymphocyte Ratio as a Novel Prognostic Marker of Upper Tract Urothelial Carcinoma After Radical Nephroureterectomy

This study aimed to evaluate the preoperative prognostic value of systemic inflammation response index and platelet-to-lymphocyte ratio (SIRI-PLR) in patients with upper tract urothelial carcinoma (UTUC). The prognostic ability of SIRI-PLR was evaluated in a training cohort comprising 259 patients with UTUC who underwent radical nephroureterectomy and was further validated in an independent cohort comprising of 274 patients. Multivariate Cox regression models showed that SIRI was significantly associated with overall-survival (OS), cancer-specific survival (CSS), and metastatic-free survival (MFS), and PLR significantly affected OS and CSS (all P < 0.05). In particular, a simultaneously high SIRI-PLR value was considered an independent risk factor even after adjusting for confounding factors and was superior to SIRI alone in predicting survival among patients with UTUC. The analyses of concordance-index and receiver operating characteristic curve showed that incorporation of SIRI-PLR vs. without its incorporation into newly developed nomograms or currently available clinical parameters, such as pathologic T stage, N stage, or tumor grade, had higher accuracy in predicting urologic outcomes of patients with UTUC. These results were observed in the training cohort and were confirmed in the validation cohort. In conclusion, patients with a simultaneously high SIRI-PLR value had significantly poor prognosis. Incorporating SIRI-PLR into currently available clinical parameters can help in patient management.

Elevated platelet-to-lymphocyte corresponds with poor outcome in patients with advanced cancer receiving anti-PD-1 therapy

OBJECTIVES

The purpose of this retrospective analysis was to investigate the prognostic value of PLR for PD-1 inhibitors.

METHODS

Patients were divided into different subgroups according to PLR. Univariate survival analysis and a multivariate Cox proportional hazards regression model were used to assess the association between PLR and overall survival (OS) or progression-free survival (PFS).

RESULTS

The optimal cut-off value of baseline PLR was 164. Among the total 85 patients, 34 patients presented with PLR ≥ 164, and 51 presented with PLR < 164, respectively. The median OS for the high PLR group was 7.0 months (95% CI: 4.1-9.9 months), and it was not reached for the low PLR group (P < 0.001). The median PFS was 3.0 months (95% CI: 1.9-4.1 months) vs. 9.8 months (95% CI: 6.1-13.5 months) for the high and low PLR groups, respectively (P < 0.001). In multivariate analysis, a PLR > 164 and body mass index (BMI) > 24.0 were independently associated with OS (hazard ratio [HR]: 3.549, 95% confidence interval [CI]: 1.901-6.625, P < 0.001 and HR: 0.496, 95% CI: 0.260-0.945, P = 0.033), meanwhile PLR was also significantly associated with inferior PFS (HR: 2.567, 95% CI: 1.551-4.249, P < 0.001). Disease control rate for high and low PLR group was 38.2% and 74.5%, respectively, and it was also correlated with elevated PLR (P = 0.001).

CONCLUSION

This retrospective analysis indicates that PLR could be used as a biomarker to stratify patients who will have a better response to anti-PD-1 agents.

Prognostic value of thrombocytosis in patients undergoing surgery for colorectal cancer with synchronous liver metastases

PURPOSE

The purpose of this study was to evaluate the prognostic role of thrombocytosis in patients with synchronous colorectal liver metastases (CRLM).

METHODS

Retrospective analysis of patients who underwent surgery for colorectal cancer with synchronous CRLM at the Division of General and Hepatobiliary Surgery, University of Verona Hospital Trust between 2005 and 2016.

RESULTS

One hundred and ninety-six patients met the inclusion criteria. High platelet count (H-PC) was found in 32%, and it was associated with a higher rate of palliative surgery (p < 0.001), extra-hepatic metastases (p < 0.001), bilobar liver disease (p = 0.007), presence of more than three metastases (p = 0.005), biggest metastasis larger than 5 cm (p < 0.001), and CEA level higher than 200 ng/mL (p = 0.035). H-PC was significantly associated with poorer 5-year overall survival (14.3% vs. 34.3%; p = 0.001). At the multivariate analysis on R0-1 cases, platelet count resulted the only independent predictor of survival (HR 2.07, p = 0.036).

CONCLUSION

H-PC correlates with the main negative clinical-pathological factors in patients with synchronous CRLM, as well as with overall survival. Moreover, it was the only independent prognostic factor in those who underwent curative surgery.

Combination of the Preoperative Systemic Immune-Inflammation Index and Monocyte-Lymphocyte Ratio as a Novel Prognostic Factor in Patients with Upper-Tract Urothelial Carcinoma

BACKGROUND

This study aimed to evaluate the clinical significance of the preoperative systemic immune-inflammation index (SII) combined with the monocyte-lymphocyte ratio (MLR) for patients with upper-tract urothelial carcinoma (UTUC).

METHODS

The clinical data of 424 patients who underwent radical nephroureterectomy from January 2007 to June 2017 were analyzed. Kaplan-Meier analyses and Cox proportional hazards models were used to evaluate associations of preoperative systemic immune-inflammatory biomarkers with overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS). Moreover, logistic regression preoperative models were applied to predict advanced disease.

RESULTS

Multivariate analyses showed that SII significantly influenced both OS and CSS (both P < 0.05), whereas MLR exhibited the most significant association with OS (P = 0.008). In particular, simultaneously high SII and MLR values correlated significantly with OS, CSS, and PFS (all P < 0.05). Logistic regression preoperative models showed that the combination of high SII and high MLR was a significant predictor of non-organ-confined UTUC (P = 0.001). Furthermore, Kaplan-Meier analysis showed that the combination of high SII and high MLR was significantly linked with poor OS, CSS, and PFS in non-organ-confined UTUC (all P < 0.05).

CONCLUSION

The study reviewed serum inflammation biomarkers in a subset of patients with UTUC and demonstrated the ability of combined SII and MLR to predict disease progression and survival. Patients with both high SII and high MLR were significantly more likely to have non-organ-confined disease and poor survival outcomes.

Natural killer cell-based immunotherapy: From transplantation toward targeting cancer stem cells

Natural killer (NK) cells are key players of the innate immune system. NK cells provide protection against infectious pathogens and malignancies in cell. This characteristic may be attributable to their intrinsic diverse potentialities and also their cooperation with adaptive immune lymphocytes, known as B and T cells. The growth, recurrence, and metastasis of cancer cells, and the failure of cytoreductive therapies against cancer cells are due to the small population of intratumor stem-like cells, called cancer stem cells (CSCs). Furthermore, NK cells can efficiently eradicate heterogeneous tumor cells after a long-term treatment. Therefore, NK cell-based therapy is a promising strategy to target and break CSC-associated resistance to anticancer drugs treatment. In this review, we have presented an overview of the emerging knowledge of the characteristics, diversities, and mechanism-driven immune surveillance of human NK cells and advances in NK cell-based immunotherapies. Finally, we will discuss how these cells can be applied to introduce the next generation of vaccine- and immune-based approaches to prevent drug resistance.

Platelets impair natural killer cell reactivity and function in endometriosis through multiple mechanisms

Study question

Do platelets have any role in the reduced cytotoxicity of natural killer (NK) cells in endometriosis?

Summary answer

Platelets impair NK cell reactivity and function in endometriosis through multiple mechanisms.

What is known already

Platelets play an important role in the development of endometriosis, and platelet-derived transforming growth factor-β1 (TGF-β1) suppresses the expression of NK Group 2, Member D (NKG2D) on NK cells, resulting in reduced cytotoxicity in women with endometriosis.

Study design size, duration

Experiments on mice with induced endometriosis in which either platelets, NK cells or both were depleted and controls (none depleted). In vitro experiments with NK cells, platelets and, as target cells, endometriotic epithelial cell and endometrial stromal cell lines.

Participants/materials setting methods

Immunohistochemistry analysis of ectopic endometrial tissues from mice with induced endometriosis receiving either platelet depletion (PD), NK cell depletion, or both or none. Immunofluorescence, flow cytometry and gene expression analysis for major histocompatibility complex class I (MHC-I) expression in target cells. Cytotoxicity and degranulation assays and the measurement of interferon (IFN)-γ secretion for the evaluation of NK cytotoxicity. Flow cytometry and gene expression for the expression of NK cell receptors.

Main results and the role of chance

PD resulted in significantly reduced lesion weight in mice with induced endometriosis, but NK cell depletion as well as concomitant platelet and NK cell depletion increased the weight, suggesting that the anti-endometriosis effect of PD is mediated, at least in part, by increased NK cell cytotoxicity against endometriotic cells. Co-incubation of target cells with platelets resulted in rapid platelet coating as well as increased MHC-I expression in these cells, effectively providing a cloak of 'pseudo-self' to these cells to shield against NK cell lysis. It also reduced the expression of NKG2D ligands MICA and MICB and reduced the NK cell cytotoxicity. In addition, co-incubation of NK cells with platelets impaired the NK cell cytotoxicity as well. This impaired NK cell cytotoxicity was not due to the increased NK cell apoptosis, but, rather, through reduced NK cell degranulation and IFN-γ production, and reduced expression of activating receptors NKG2D and NKp46 and increased expression of inhibitory receptor KIR2DL1 in NK cells. Inhibition of TGF-β1 signaling partially restored the aberrant expression of NKG2D, NKp46 and KIR2DL1, and partially restored the impaired NK cell cytotoxicity induced by activated platelets and their releasate.

Large scale data

Not applicable.

Limitations reasons for caution

This study is confined by the limitation of animal and in vitro experimentation and the lack of direct human data.

Wider implications of the findings

Anti-platelet treatment holds promise in treating endometriosis.

Study funding/competing interests

The National Natural Science Foundation of China (81471434 to S.W.G., 81270676 to S.W.G., 81370695 to X.S.L. and 81671436 to X.S.L). None of the authors has anything to disclose.

Platelet Integrins in Tumor Metastasis: Do They Represent a Therapeutic Target?

Platelets are small anucleated cell fragments that ensure the arrest of bleeding after a vessel wall injury. They are also involved in non-hemostatic function such as development, immunity, inflammation, and in the hematogeneous phase of metastasis. While the role of platelets in tumor metastasis has been recognized for 60 years, the molecular mechanism underlying this process remains largely unclear. Platelets physically and functionally interact with various tumor cells through surface receptors including integrins. Platelets express five integrins at their surface, namely α2β1, α5β1, α6β1, αvβ3, and αIIbβ3, which bind preferentially to collagen, fibronectin, laminin, vitronectin, and fibrinogen, respectively. The main role of platelet integrins is to ensure platelet adhesion and aggregation at sites of vascular injury. Two of these, α6β1 and αIIbβ3, were proposed to participate in platelet–tumor cell interaction and in tumor metastasis. It has also been reported that pharmacological agents targeting both integrins efficiently reduce experimental metastasis, suggesting that platelet integrins may represent new anti-metastatic targets. This review focuses on the role of platelet integrins in tumor metastasis and discusses whether these receptors may represent new potential targets for novel anti-metastatic approaches.

Platelets are versatile cells: New discoveries in hemostasis, thrombosis, immune responses, tumor metastasis and beyond

Platelets are small anucleate blood cells generated from megakaryocytes in the bone marrow and cleared in the reticuloendothelial system. At the site of vascular injury, platelet adhesion, activation and aggregation constitute the first wave of hemostasis. Blood coagulation, which is initiated by the intrinsic or extrinsic coagulation cascades, is the second wave of hemostasis. Activated platelets can also provide negatively-charged surfaces that harbor coagulation factors and markedly potentiate cell-based thrombin generation. Recently, deposition of plasma fibronectin, and likely other plasma proteins, onto the injured vessel wall has been identified as a new "protein wave of hemostasis" that may occur even earlier than the first wave of hemostasis, platelet accumulation. Although no experimental evidence currently exists, it is conceivable that platelets may also contribute to this protein wave of hemostasis by releasing their granule fibronectin and other proteins that may facilitate fibronectin self- and non-self-assembly on the vessel wall. Thus, platelets may contribute to all three waves of hemostasis and are central players in this critical physiological process to prevent bleeding. Low platelet counts in blood caused by enhanced platelet clearance and/or impaired platelet production are usually associated with hemorrhage. Auto- and allo-immune thrombocytopenias such as idiopathic thrombocytopenic purpura and fetal and neonatal alloimmune thrombocytopenia may cause life-threatening bleeding such as intracranial hemorrhage. When triggered under pathological conditions such as rupture of an atherosclerotic plaque, excessive platelet activation and aggregation may result in thrombosis and vessel occlusion. This may lead to myocardial infarction or ischemic stroke, the major causes of mortality and morbidity worldwide. Platelets are also involved in deep vein thrombosis and thromboembolism, another leading cause of mortality. Although fibrinogen has been documented for more than half a century as essential for platelet aggregation, recent studies demonstrated that fibrinogen-independent platelet aggregation occurs in both gene deficient animals and human patients under physiological and pathological conditions (non-anti-coagulated blood). This indicates that other unidentified platelet ligands may play important roles in thrombosis and might be novel antithrombotic targets. In addition to their critical roles in hemostasis and thrombosis, emerging evidence indicates that platelets are versatile cells involved in many other pathophysiological processes such as innate and adaptive immune responses, atherosclerosis, angiogenesis, lymphatic vessel development, liver regeneration and tumor metastasis. This review summarizes the current knowledge of platelet biology, highlights recent advances in the understanding of platelet production and clearance, molecular and cellular events of thrombosis and hemostasis, and introduces the emerging roles of platelets in the immune system, vascular biology and tumorigenesis. The clinical implications of these basic science and translational research findings will also be discussed.

NK cells and cancer: you can teach innate cells new tricks

Natural killer (NK) cells are the prototype innate lymphoid cells endowed with potent cytolytic function that provide host defence against microbial infection and tumours. Here, we review evidence for the role of NK cells in immune surveillance against cancer and highlight new therapeutic approaches for targeting NK cells in the treatment of cancer.

Preoperative platelet to lymphocyte ratio predicts outcome of patients with pancreatic ductal adenocarcinoma after pancreatic resection

BACKGROUND

Inflammation plays a crucial role in tumor growth, metastasis, and survival. The preoperative platelet-to-lymphocyte ratio (PLR) has been reported as a significant prognostic indicators in several digestive malignancies. Our objective was to evaluate whether preoperative PLR is a prognostic index in resected pancreatic ductal adenocarcinoma.

METHODS

Data from 131 patients who underwent pancreatic resection for pancreatic ductal adenocarcinoma were available from a prospectively maintained database. The patients were divided into groups according to a preoperative PLR of <150 or ≥150. Survival data were analyzed.

RESULTS

In univariate and multivariate analyses, a preoperative PLR of ≥150 was a significant and independent risk factor for cancer recurrence and poor survival, respectively (disease-free survival [DFS]; P= .0014, P = .047; OS, P ≤ .01each). Similarly, lymph node metastasis, and moderate or poor differentiation were independent risk factors for cancer recurrence, whereas tumor diameter, positive surgical margin, and moderate or poor differentiation were independent risk factors for poor patient survival (P ≤ .05 each).

CONCLUSION

The preoperative PLR in patients with pancreatic ductal adenocarcinoma was an independent predictor in DFS and overall survival after elective resection. Measurement of the PLR may help decision making in the postoperative management of patients with pancreatic ductal adenocarcinoma.

Hypercoagulation in colorectal cancer: what can platelet indices tell us?

Colorectal cancer, as all solid malignancies, is accompanied by changes in the haemostatic mechanism favoring the establishment of a thrombotic potential, with platelets playing a key-role in this framework; they further link colorectal cancer progression and hypercoagulation with the immune-response against the neoplastic spread. Under this rationale, various studies have assessed the use of platelet indices as prognostic markers of the biological behavior of colorectal cancer, demonstrating significant results. We herein attempt to summarize in a narrative and critical approach the relevant available data and the underlying pathophysiology, stressing the necessity of a more thorough understanding and future implementation of platelet indices in all stages of care we deliver to colorectal cancer patients.

Regulation of tumor growth and metastasis: the role of tumor microenvironment

The presence of abnormal cells with malignant potential or neoplastic characteristics is a relatively common phenomenon. The interaction of these abnormal cells with their microenvironment is essential for tumor development, protection from the body's immune or defence mechanisms, later progression and the development of life-threatening or metastatic disease. The tumor microenvironment is a collective term that includes the tumor's surrounding and supportive stroma, the different effectors of the immune system, blood platelets, hormones and other humoral factors. A better understanding of the interplay between the tumor cells and its microenvironment can provide efficient tools for cancer management, as well as better prevention, screening and risk assessment protocols.

Iron-induced parafibrin formation in tumors fosters immune evasion

Although efficacious in vitro, it is well known that adoptive immunotherapeutic modalities lose their potency when applied in vivo. Furthermore, malignant cell exposure to blood platelets attenuates the anticancer activity of natural killer (NK) cells. We argue that upon contact with redox iron, fibrinogen is converted to a hydrophobic fibrin-like polymer that coats tumor cells and provides protection from immune-mediated destruction.

Platelets effects on tumor growth

Unlike other blood cells, platelets are small anucleate structures derived from marrow megakaryocytes. Thought for almost a century to possess solely hemostatic potentials, platelets, however, play a much wider role in tissue regeneration and repair and interact intimately with tumor cells. On one hand, tumor cells induce platelet aggregation (TCIPA), known to act as the trigger of cancer-associated thrombosis. On the other hand, platelets recruited to the tumor microenvironment interact, directly, with tumor cells, favoring their proliferation, and, indirectly, through the release of a wide palette of growth factors, including angiogenic and mitogenic proteins. In addition, the role of platelets is not solely confined to the primary tumor site. Indeed, they escort tumor cells, helping their intravasation, vascular migration, arrest, and extravasation to the tissues to form distant metastasis. As expected, nonspecific or specific inhibition of platelets and their content represents an attractive novel approach in the fight against cancer. This review illustrates the role played by platelets at primary tumor sites and in the various stages of the metastatic process.

Natural history of hepatic metastases from colorectal cancer - pathobiological pathways with clinical significance

Colorectal cancer hepatic metastases represent the final stage of a multi-step biological process. This process starts with a series of mutations in colonic epithelial cells, continues with their detachment from the large intestine, dissemination through the blood and/or lymphatic circulation, attachment to the hepatic sinusoids and interactions with the sinusoidal cells, such as sinusoidal endothelial cells, Kupffer cells, stellate cells and pit cells. The metastatic sequence terminates with colorectal cancer cell invasion, adaptation and colonisation of the hepatic parenchyma. All these events, termed the colorectal cancer invasion-metastasis cascade, include multiple molecular pathways, intercellular interactions and expression of a plethora of chemokines and growth factors, and adhesion molecules, such as the selectins, the integrins or the cadherins, as well as enzymes including matrix metalloproteinases. This review aims to present recent advances that provide insights into these cell-biological events and emphasizes those that may be amenable to therapeutic targeting.

The platelet-cancer loop

The relationship between cancer and thrombosis has been established since 1865 when Armand Trousseau described superficial thrombophlebitis as forewarning sign of occult visceral malignancy. Platelets are the primary hemostatic tool and play a primordial role in cancer-induced thrombosis. Tumor-induced numerical and functional platelet abnormalities have been described in conjunction to changes in coagulation. Such changes are reported even in the absence of clinically detectable thrombosis and correlate with tumor progression and metastasis. Reciprocally, platelets seem to interplay with the tumors and the immune system, both directly and indirectly favoring tumor progressions, tethering and distant spread. A number of growth factors supporting tumor growth, angiogenesis and metastasis are released from the platelets. A reciprocating loop of tumor-induced platelet activation/platelet-induced tumor growth and dissemination is initiated, acting as a thrombosis trigger/tumor amplifier. Recent studies have demonstrated that the use of anti-platelet agents can break this loop resulting in a reduction of short-term risk for incident cancer, cancer mortality and metastasis. The beneficial effect in reduction in cancer-induced thrombosis remains to be established. The current review aims at shedding the light on the intimate reciprocal cross-talk between platelets and cancer and on exploring the potential beneficial effect of anti-platelet agents in breaking the deadly loop of tumor amplification.

Crosstalk between Platelets and the Immune System: Old Systems with New Discoveries

Platelets are small anucleate cells circulating in the blood. It has been recognized for more than 100 years that platelet adhesion and aggregation at the site of vascular injury are critical events in hemostasis and thrombosis; however, recent studies demonstrated that, in addition to these classic roles, platelets also have important functions in inflammation and the immune response. Platelets contain many proinflammatory molecules and cytokines (e.g., P-selectin, CD40L, IL-1β, etc.), which support leukocyte trafficking, modulate immunoglobulin class switch, and germinal center formation. Platelets express several functional Toll-like receptors (TLRs), such as TLR-2, TLR-4, and TLR-9, which may potentially link innate immunity with thrombosis. Interestingly, platelets also contain multiple anti-inflammatory molecules and cytokines (e.g., transforming growth factor-β and thrombospondin-1). Emerging evidence also suggests that platelets are involved in lymphatic vessel development by directly interacting with lymphatic endothelial cells through C-type lectin-like receptor 2. Besides the active contributions of platelets to the immune system, platelets are passively targeted in several immune-mediated diseases, such as autoimmune thrombocytopenia, infection-associated thrombocytopenia, and fetal and neonatal alloimmune thrombocytopenia. These data suggest that platelets are important immune cells and may contribute to innate and adaptive immunity under both physiological and pathological conditions.