Thrombocytosis and hepatocellular carcinoma

Platelet-related phenotypic patterns in hepatocellular carcinoma patients

Small hepatocellular carcinomas (HCCs) usually arise in cirrhosis, often with associated thrombocytopenia. Many patients with large HCCs have normal blood platelet counts. In this review, we compare parameter and phenotype patterns of patients with small (≤ 3 cm) and larger HCCs. A retrospective analysis was undertaken of a 4,139-patient HCC database to compare patient demographics, and liver and tumor characteristics associated with small and large HCCs, especially with respect to platelet counts. We found that patients with larger HCCs had more tumor nodules and portal vein thrombosis (PVT) positivity, and had higher blood alpha-fetoprotein (AFP), bilirubin, and platelet counts. In patients with larger tumors and normal platelets (43.7% of the cohort), tumors were larger and AFP levels were higher, with lower bilirubin and aspartate aminotransferase (AST) levels than in patients with larger tumors and thrombocytopenia (17.5%). A parsimonious multinomial regression model showed a high odds ratio for AFP and platelets for tumors>3 cm with PVT. We conclude that platelet levels are associated with distinct large HCC phenotypes.

Presence of intratumoral platelets is associated with tumor vessel structure and metastasis

Background

Platelets play a fundamental role in maintaining hemostasis and have been shown to participate in hematogenous dissemination of tumor cells. Abundant platelets were detected in the tumor microenvironment outside of the blood vessel, thus, platelet -tumor cell interaction outside of the bloodstream may play a role in regulating primary tumor growth and metastasis initiation. However, it is unclear that platelet depletion affects tumor vessel structure and dynamics.

Methods

Using thrombocytopenia induction in two different tumor-bearing mouse models, tumor tissues were performed by Westernblotting and immunohistochemical staining. Vascular permeability was evaluated by determination of intratumoral Evans blue and Miles vascular permeability assay. Furthermore, microdialysis was used to examining the intratumoral extracellular angiogenic growth factors (VEGF, TGF-β) by ELISA.

Results

Platelet depletion showed no change in tumor growth and reduced lung metastasis. Platelet depletion led to reduced tumor hypoxia and Met receptor activation and was associated with a decreased release of MMP-2, 9, PAI-1, VEGF, and TGF-β. Tumor vessels in platelet-depleted mice showed impaired vessel density and maturation.

Conclusions

Our findings demonstrate that platelets within the primary tumor microenvironment play a critical role in the induction of vascular permeability and initiation of tumor metastasis.

Thrombocytosis as a prognostic marker in gastrointestinal cancers

Thrombocytosis is an adverse prognostic factor in many types of cancer. These include breast cancer, ovarian and other gynecologic cancers, renal cell carcinoma and lung cancers. In gastrointestinal cancers of various locations and histologic types, thrombocytosis has been reported in general to be associated with adverse clinical outcomes. Platelet count measurement is well standardized and available in every clinical laboratory, making its use as a prognostic marker practical. This paper will discuss the data on the prognostic value of thrombocytosis in gastrointestinal cancers as well as pathogenic aspects of the association that strengthen the case for its use in clinical prognostication.

Role of platelets in chronic liver disease and acute liver injury

Platelets contain not only hemostatic factors but also many growth factors that play important roles in wound healing and tissue repair. Platelets have already been used for the promotion of tissue regeneration in the clinical setting, such as dental implantation and plastic surgery. Thrombocytopenia, which is frequently found in patients with chronic liver disease and cirrhosis, is due to various causes such as decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism. However, the relationship between thrombocytopenia and hepatic pathogenesis and the role of platelets in chronic liver disease are poorly understood. In acute liver injury, it is reported that platelets are recruited to the liver and contribute to liver damage by promoting the induction of chemotactic factors and the accumulation of leukocytes in the liver, whereas platelets or mediators released by platelets can have a protective effect against liver injury. In this review, we highlight the recent accumulated knowledge concerning the role of platelets in chronic liver disease and acute liver injury.

Platelet extracts induce growth, migration and invasion in human hepatocellular carcinoma in vitro

Background

Thrombocytopenia has been reported to be associated with small size HCCs, and thrombocytosis to be associated with large size HCCs. The aim was to examine the effects of platelets in relation to HCC cell growth.

Methods

The effects of time-expired pooled normal human platelets were examined on human HCC cell line growth and invasion.

Results

Blood platelet numbers increased with increasing HCC tumor size and portal vein invasion. Platelet extracts enhanced cell growth in 4 human HCC cell lines, as well as cell migration, medium AFP levels and decreased apoptosis. Cell invasion was significantly enhanced, using a Matrigel-coated trans-well membrane and3D (Real-Time Imaging) invasion assay. Western blots showed that platelets caused enhanced phospho-ERK and phospho–JNK signaling and anti-apoptotic effect with increase of Bcl-xL (anti-apoptotic marker) and decrease of Bid (pro-apoptotic marker) levels. Their growth effects were blocked by a JNK inhibitor.

Conclusions

Platelets stimulated growth and invasion of several HCC cell lines in vitro, suggesting that platelets or platelet growth factors could be a potential pharmacological target.

Features of massive hepatocellular carcinomas

BACKGROUND

Massive hepatocellular carcinomas (HCCs) are uncommon and poorly characterized.

AIM

To characterize a large cohort of HCC patients with massive tumors, with documented baseline characteristics and survival data.

METHODS

Records were examined of a cohort of 344 biopsy-proven and randomly presenting unresectable HCC patients with tumors of at least 10 cm diameter (massive), which were analyzed for their clinical characteristics and survival.

RESULTS

Massive HCC patients were significantly different from others, in having less severe cirrhosis and higher blood platelet counts, α-fetoprotein (AFP), alkaline phosphatase (ALKP), and γ-glutamyl transpeptidase (GGTP) levels. Platelets, ALKP, and GGTP correlated with tumor size. Within massive HCCs, ALKP levels related to tumor number, whereas platelet counts related to tumor size. AFP and GGTP related to neither. All four parameters related to survival. A multivariate Cox proportional hazard model showed that ALKP and AFP were significant for overall survival. Survival of massive tumors was not significantly worse than for other larger tumors.

CONCLUSION

Massive HCCs were characterized by high blood platelets, AFP, ALKP, and GGTP levels. AFP levels were important for survival, but did not directly relate to tumor size or number, suggesting that AFP represents some other property of massive HCC biology. Patients with massive HCC should thus be considered for active therapeutic intervention, just as for other sizes of HCC.

Hepatocellular carcinoma size: platelets, γ-glutamyl transpeptidase, and alkaline phosphatase

BACKGROUND

Thrombocytopenia is a cirrhosis surrogate which is associated with hepatocellular carcinoma (HCC) development.

AIMS

To compare the clinical characteristics of HCC in the presence and absence of thrombocytopenia.

METHODS

The baseline clinical data of a large cohort of randomly presenting, biopsy-proven HCC patients was examined for phenotypic patterns, after organizing the data by tumor size and subdivision into tumor size terciles.

RESULTS

Small tumor size tercile I patients had the lowest platelet counts. Patients with higher platelets within each size tercile had the lowest bilirubin and prothrombin time and higher γ-glutamyl transpeptidase (GGTP) and alkaline phosphatase (ALKP) levels. When patients with similar platelet and bilirubin levels were compared, α-fetoprotein, GGTP, and ALKP were significantly increased in patients with larger tumors and in the presence of portal vein thrombus. Large tumor size tercile III patients without thrombocytopenia had larger tumors, higher GGTP and ALKP, and lower bilirubin levels than did patients with thrombocytopenia.

CONCLUSIONS

Thrombocytopenia occurred in 40.7% of patients with smaller tumors but only in 11.3% of patients with larger tumors. Patients without thrombocytopenia had elevated GGTP and ALKP and lower bilirubin levels, regardless of tumor size, but they also had larger tumors within the large tumor tercile.