Impact of biomarkers on disease survival and progression in patients treated with octreotide for advanced hepatocellular carcinoma

Agonists, Antagonists and Receptors of Somatostatin: Pathophysiological and Therapeutical Implications in Neoplasias

Somatostatin is a peptide that plays a variety of roles such as neurotransmitter and endocrine regulator; its actions as a cell regulator in various tissues of the human body are represented mainly by inhibitory effects, and it shows potent activity despite its physiological low concentrations. Somatostatin binds to specific receptors, called somatostatin receptors (SSTRs), which have different tissue distributions and associated signaling pathways. The expression of SSTRs can be altered in various conditions, including tumors; therefore, they can be used as biomarkers for cancer cell susceptibility to certain pharmacological agents and can provide prognostic information regarding disease evolution. Moreover, based on the affinity of somatostatin analogs for the different types of SSTRs, the therapeutic range includes conditions such as tumors, acromegaly, post-prandial hypotension, hyperinsulinism, and many more. On the other hand, a number of somatostatin antagonists may prove useful in certain medical settings, based on their differential affinity for SSTRs. The aim of this review is to present in detail the principal characteristics of all five SSTRs and to provide an overview of the associated therapeutic potential in neoplasias.

Standard of Care Versus Octreotide in Angiodysplasia-Related Bleeding (the OCEAN Study): A Multicenter Randomized Controlled Trial

BACKGROUND & AIMS

Gastrointestinal angiodysplasias are vascular anomalies that may result in transfusion-dependent anemia despite endoscopic therapy. An individual patient data meta-analysis of cohort studies suggests that octreotide decreases rebleeding rates, but component studies possessed a high risk of bias. We investigated the efficacy of octreotide in reducing the transfusion requirements of patients with angiodysplasia-related anemia in a clinical trial setting.

METHODS

The study was designed as a multicenter, open-label, randomized controlled trial. Patients with angiodysplasia bleeding were required to have had at least 4 red blood cell (RBC) units or parental iron infusions, or both, in the year preceding randomization. Patients were allocated (1:1) to 40-mg octreotide long-acting release intramuscular every 28 days or standard of care, including endoscopic therapy. The treatment duration was 1 year. The primary outcome was the mean difference in the number of transfusion units (RBC + parental iron) between the octreotide and standard of care groups. Patients who received at least 1 octreotide injection or followed standard of care for at least 1 month were included in the intention-to-treat analyses. Analyses of covariance were used to adjust for baseline transfusion requirements and incomplete follow-up.

RESULTS

We enrolled 62 patients (mean age, 72 years; 32 men) from 17 Dutch hospitals in the octreotide (n = 31) and standard of care (n = 31) groups. Patients required a mean number of 20.3 (standard deviation, 15.6) transfusion units and 2.4 (standard deviation, 2.0) endoscopic procedures in the year before enrollment. The total number of transfusions was lower with octreotide (11.0; 95% confidence interval [CI], 5.5-16.5) compared with standard of care (21.2; 95% CI, 15.7-26.7). Octreotide reduced the mean number of transfusion units by 10.2 (95% CI, 2.4-18.1; P = .012). Octreotide reduced the annual volume of endoscopic procedures by 0.9 (95% CI, 0.3-1.5).

CONCLUSIONS

Octreotide effectively reduces transfusion requirements and the need for endoscopic therapy in patients with angiodysplasia-related anemia.

CLINICALTRIALS

gov, NCT02384122.

The State-of-the-Art Mechanisms and Antitumor Effects of Somatostatin in Colorectal Cancer: A Review

Somatostatin, a somatotropin release inhibiting factor (SST, SRIF), is a widely distributed multifunctional cyclic peptide and acts through a transmembrane G protein-coupled receptor (SST1-SST5). Over the past decades, research has begun to reveal the molecular mechanisms underlying the anticancer activity of this hormonal peptide. Among gastrointestinal tract (GIT) tumors, direct and indirect antitumor effects of SST have been documented best in gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and less well in non-endocrine cancers, including sporadic colorectal cancer (CRC). In the latter, the signaling pathways involved in the antitumor function of SST are primarily MAPK/ERK/AKT and Wnt/β-catenin. Direct (involving the MAPK pathway) and indirect (VEGF production) antiangiogenic effects of SST in CRC have also been described. The anti-inflammatory role of SST in CRC is emphasized, but detailed molecular mechanisms are still being explored. The role of SST in tumor genome/tumor microenvironment (TME)/host's gut microbiome interactions is only partially known. The results of SST analogues (SSAs)' treatment of sporadic CRC in monotherapy in vivo are not spectacular. The current review aims to present the state-of-the-art mechanisms and antitumor activity of endogenous SST and its synthetic analogues in CRC, with particular emphasis on sporadic CRC.

Antitumoral and Anti-inflammatory Roles of Somatostatin and Its Analogs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and affects about 8% of cirrhotic patients, with a recurrence rate of over 50%. There are numerous therapies available for the treatment of HCC, depending on cancer staging and condition of the patient. The complexity of the treatment is also justified by the unique pathogenesis of HCC that involves intricate processes such as chronic inflammation, fibrosis, and multiple molecular carcinogenesis events. During the last three decades, multiple in vivo and in vitro experiments have used somatostatin and its analogs (SSAs) to reduce the proliferative and metastatic potential of hepatoma cells by inducing their apoptosis and reducing angiogenesis and the inflammatory component of HCC. Most experiments have proven successful, revealing several different pathways and mechanisms corresponding to the aforementioned functions. Moreover, a correlation between specific effects and expression of somatostatin receptors (SSTRs) was observed in the studied cells. Clinical trials have tested either somatostatin or an analog, alone or in combination with other drugs, to explore the potential effects on HCC patients, in various stages of the disease. While the majority of these clinical trials exhibited minor to moderate success, some other studies were inconclusive or even reported negative outcomes. A complete evaluation of the efficacy of somatostatin and SSAs is still the matter of intense debate, and, if deemed useful, these substances may play a beneficial role in the management of HCC patients.

Hepatocellular Carcinoma Mimicking Neuroendocrine Tumor Metastasis on 68Ga-DOTATATE PET/CT

Ga-DOTATATE is a radiolabeled somatostatin analog used for the detection and characterization of somatostatin receptor (SSR)-overexpressing tumors, particularly well-differentiated neuroendocrine tumors. We present a case of a 65-year-old man with well-differentiated pancreatic neuroendocrine tumor post-Whipple surgery and a new liver lesion on CT. Ga-DOTATATE PET/CT was performed for SSR characterization and restaging, which demonstrated the lesion to be intensely SSR positive and interpreted as a neuroendocrine metastasis. However, subsequent pathology proved the lesion to be a hepatocellular carcinoma. This case adds hepatocellular carcinoma as a potentially DOTATATE-avid malignancy to be considered in the differential diagnoses of SSR-positive liver lesions.

Serum insulin-like growth factor-1 and its binding protein 3 as prognostic factors for the incidence, progression, and outcome of hepatocellular carcinoma: a systematic review and meta-analysis

Purpose

Previous studies have supported an association between serum insulin-like growth factor-1 (IGF1) and IGF-binding protein 3 (IGFBP3) levels and hepatocellular carcinoma (HCC), but the results were inaccurate. It has recently been proposed that IGF1 and IGFBP3 play roles in the time-to-progression (TTP) and overall survival (OS) of HCC patients. Our results revealed that serum IGF1 level is predictive of the progression and survival of HCC patients.

Results

HCC was associated with a significant reduction in serum IGF-1 and IGFBP-3 levels compared to cirrhosis (p = 0.037). Low serum IGF1 levels were predictive of a shorter TTP (OR, 2.74; 95% confidence interval [CI], 1.92–3.90) and poorer OS (odds ratio [OR], 2.20; 95% CI, 1.81–2.68) in HCC patients. The IGF1/IGFBP3 molar ratio was not significantly associated with the risk of HCC (OR, 1.311; 95% CI, 0.761–2.260).

Materials and Methods

We conducted a comprehensive literature search in PubMed, EMBASE, and the Cochrane Library. Twenty studies met the inclusion criteria and were subjected to statistical analysis. The geometric mean and standard deviation (SD) of serum IGF1 and IGFBP3 levels in the healthy, cirrhosis, and HCC groups were calculated. Pooled odds ratios (ORs) were calculated using a fixed-effects model to analyse the association of serum IGF1 level with the progression and survival of HCC patients.

Conclusions

Serum IGF1 and IGFBP3 levels were positively associated with the incidence of HCC. Serum IGF1 level is an independent prognostic factor for the progression and survival of HCC patients.

Tissue- and Serum-Associated Biomarkers of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), one of the leading causes of cancer deaths in the world, is offering a challenge to human beings, with the current modes of treatment being a palliative approach. Lack of proper curative or preventive treatment methods encouraged extensive research around the world with an aim to detect a vaccine or therapeutic target biomolecule that could lead to development of a drug or vaccine against HCC. Biomarkers or biological disease markers have emerged as a potential tool as drug/vaccine targets, as they can accurately diagnose, predict, and even prevent the diseases. Biomarker expression in tissue, serum, plasma, or urine can detect tumor in very early stages of its development and monitor the cancer progression and also the effect of therapeutic interventions. Biomarker discoveries are driven by advanced techniques, such as proteomics, transcriptomics, whole genome sequencing, micro- and micro-RNA arrays, and translational clinics. In this review, an overview of the potential of tissue- and serum-associated HCC biomarkers as diagnostic, prognostic, and therapeutic targets for drug development is presented. In addition, we highlight recently developed micro-RNA, long noncoding RNA biomarkers, and single-nucleotide changes, which may be used independently or as complementary biomarkers. These active investigations going on around the world aimed at conquering HCC might show a bright light in the near future.

Hepatocellular carcinoma: Exploring the impact of ethnicity on molecular biology

Hepatocellular carcinoma (HCC) is the sixth most common cancer in the world and the third leading cause of cancer-related death. The high rate of diagnosis in non-curable stages and the lack of novel active treatments make it necessary to review all the possible sources of misleading results in this scenario. The incidence of HCC shows clear geographical variation with higher annual incidence in Asia and Africa than in Western countries; we aimed to review the literature to find if there are different trends in the main activated molecular pathways. Hyperactivation of RAS/RAF/MEK/ERK and PI3K/AKT/mTOR signalling and epithelial to mesenchymal transition (EMT) process are more prevalent in the Western population; however, fibroblast growth factor (FGF), transforming growth factor β (TGFβ) and Notch pathways seems to be more relevant in Asian population. Whether these variations just reflect the distinct distribution of known causes of HCC or proper ethnical differences remain to be elucidated. Nevertheless, these clearly different patterns are relevant to regional or worldwide clinical trial design. If this information is neglected by sponsors and researchers the rate of failure in HCC trials will not improve.

Predictive value of serum insulin-like growth factor-1 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the commonest primary malignant cancer of the liver in the world. Insulin-like growth factor-1 (IGF-1) levels reflect hepatic function and are inversely correlated with the severity of background chronic liver disease.

OBJECTIVE

This study evaluated whether basal serum IGF-1 levels can predict prognosis of HCC patients according to different risks of disease progression.

MATERIALS AND METHODS

A total of 89 patients with hepatocellular carcinoma (HCC) were recruited in 3 groups: Group I, 30 HCC patients receiving sorafinib; Group II, 30 HCC patients with best supportive care; and Group III include 29 patients undergoing transcatheter arterial chemoembolization (TACE). All patients were investigated for serum levels of AST, ALP, Bb, Cr, BUN, AFP and IGF-I.

RESULTS

Patients with disease control had significantly higher baseline IGF-1 levels 210 (185-232.5) ng/mL (p value<0.01) than did patients without disease control. Low basal IGF-1 levels were associated with advanced HCC, such as multiple tumors and advanced stage, and low IGF-1 levels predicted shorter TTP and overall survival in patients treated with TACE.

CONCLUSIONS

The levels of serum IGF-1, expressed as continuous values, may be helpful for accurately assessing hepatic function and the prognostic stratification of patients with HCC.

Serum VEGF level is associated with the outcome of patients with hepatocellular carcinoma: a meta-analysis

BACKGROUND

Hepatocellular carcinoma (HCC) is a highly vascular tumor that expresses vascular endothelial growth factor (VEGF). Various studies have evaluated the prognostic value of VEGF levels in HCC, but yielded conflicting results.

METHODS

Electronic databases updated to June 2013 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between serum VEGF level and survival of patients with HCC. Survival data were aggregated and quantitatively analyzed.

RESULTS

We performed a meta-analysis of 11 studies that evaluated the correlation between serum VEGF level and survival in patients with HCC. Combined hazard ratios suggested that serum VEGF level had an unfavorable impact on overall survival (OS) [hazard ratio (HR) =1.88, 95% confidence interval (CI): 1.46-2.30], and disease free survival (DFS) (HR=2.27, 95% CI: 1.55-2.98) in patients with HCC. No significant heterogeneity was observed among all studies.

CONCLUSIONS

Serum high VEGF level indicates a poor prognosis for patients with hepatocellular carcinoma.

Somatostatin analogs therapy in gastroenteropancreatic neuroendocrine tumors: current aspects and new perspectives

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare tumors that present many clinical features secreting peptides and neuroamines that cause distinct clinical syndromes such as carcinoid syndrome. However most of them are clinically silent until late presentation with mass effects. Surgical resection is the first line treatment for a patient with a GEP-NET while in metastatic disease multiple therapeutic approaches are possible. GEP-NETs are able to express somatostatin receptors (SSTRs) bounded by somatostatin (SST) or its synthetic analogs, although the subtypes and number of SSTRs expressed are very variable. In particular, SST analogs are used frequently to control hormone-related symptoms while their anti-neoplastic activity seems to result prevalently in tumor stabilization. Patients who fail to respond or cease to respond to standard SST analogs treatment seem to have a response to higher doses of these drugs. For this reason, the use of higher doses of SST analogs will probably improve the clinical management of these patients.

Modelling survival in hepatocellular carcinoma

OBJECTIVES

To identify the pattern of the risk of death over long-term in unresectable hepatocellular carcinoma by determining the appropriate distribution to extrapolate overall survival and to assess the role of the Weibull distribution as the standard survival model in oncology.

RESEARCH DESIGN AND METHODS

To select the appropriate distribution, three types of data sources have been analysed. Patient level data from two randomized controlled trials and published Kaplan-Meier curves from a systematic literature review provided short term follow-up data. They were supplemented with patient level data, with long-term follow-up from the Cancer Institute New South Wales, Australia. Published Kaplan-Meier curves were read in and a time-to-event dataset was created. Distributions were fitted to the data from the different sources separately. Their fit was assessed visually and compared using statistical criteria based on log-likelihood, the Akaike information criterion (AIC), and the Bayesian information criterion (BIC).

RESULTS

Based on both published and patient-level, and both short- and long-term follow-up data, the Weibull distribution, used very often in cost-effectiveness models in oncology, does not seem to offer a good fit in hepatocellular carcinoma among the different survival models. The best fitting distribution appears to be the lognormal, with loglogistic as the second-best fitting function. Results were consistent between the different sources of data.

CONCLUSIONS

In unresectable hepatocellular carcinoma, the Weibull model, which is often treated at the gold standard, does not appear to be appropriate based on different sources of data (two clinical trials, a retrospective database and published Kaplan-Meier curves). Lognormal distribution seems to be the most appropriate distribution for extrapolating overall survival.

Serum insulin-like growth factor-1 levels predict outcomes of patients with advanced hepatocellular carcinoma receiving antiangiogenic therapy

PURPOSE

Patients with liver cirrhosis or hepatocellular carcinoma (HCC) have decreased serum insulin-like growth factor (IGF)-1 levels. We evaluated whether IGF-1 levels were associated with the outcomes of patients with advanced HCC treated with systemic antiangiogenic therapy.

EXPERIMENTAL DESIGN

The study was based on patients with advanced HCC who were enrolled in two clinical trials evaluating first-line combination antiangiogenic therapy. Serum samples were collected before treatment and four to six weeks after the start of treatment. The levels of IGF-1, IGF-2, and IGF-binding protein-3 (IGFBP3) were analyzed for their associations with treatment outcomes.

RESULTS

A total of 83 patients were included in the study. Patients who had high (≥the median level) baseline IGF-1 levels had significantly higher disease control rate (DCR) than patients who had low (<the median level) levels (71% vs. 39%, P = 0.003). The levels of posttreatment IGF-1, and pre- or posttreatment IGF-2 and IGFBP3 were not associated with DCR. Patients with high baseline IGF-1 levels, compared with patients with low levels, had significantly longer progression-free survival (PFS; median, 4.3 vs. 1.9 months, P = 0.014) and overall survival (OS; median, 10.7 vs. 3.9 months, P = 0.009). The high baseline IGF-1 level remains an independent factor associated with favorable PFS and OS in multivariate analysis.

CONCLUSIONS

High pretreatment IGF-1 levels were associated with better DCR, PFS, and OS of patients who received antiangiogenic therapy for advanced HCC. This finding warrants validation in large studies.

High expression of p300 in HCC predicts shortened overall survival in association with enhanced epithelial mesenchymal transition of HCC cells

P300 impacts the transcription of several genes involved in biological behavior of human malignancies including hepatocellular carcinomas (HCC). We found p300 is highly expressed in 47% of surgically resected HCC specimens by immunohistochemistry, which correlated with advanced TNM staging (P = 0.034), vascular invasion (P = 0.036), intrahepatic metastasis (P = 0.001) and shortened overall survival (P = 0.028). In vitro study, knocking down of p300 expression in hepatoma cells recovered E-cadherin expression, inhibited the translocation of beta (β)-catenin into the nuclei, decreased cyclin D1 activity and suppressed the migration/invasion of HCC cells. Furthermore, suppression of p300 led to down-regulation of epithelial-mesenchymal transition (EMT)-related molecules such as Snail, Twist and HIF-1 alpha. These observations suggest that p300 contributes to the EMT-related progression of HCCs.

Somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine tumours, current aspects and new perspectives

Gastroenteropancreatic neuroendocrine tumours (GEP NETs) are rare tumours that present many clinical features.They secrete peptides and neuroamines that cause distinct clinical syndromes, including carcinoid syndrome. However, many are clinically silent until late presentation with mass effects.In 2000 the WHO developed a new classification which gives a better description of the characteristics and biological behaviour of the tumour.Surgical resection is the treatment of first choice for a patient with a GEP NET. In metastatic disease multiple therapeutic approaches are possible. In these cases the goal is to improve quality of life and to extent survival.GEP NETs express somatostatin receptors (SSTRs), which are bound by somatostatin (SST) or its synthetic analogues, although the subtypes and number of SSTRs expressed is very variable.Somatostatin analogues are used frequently to control hormone-related symptoms while their anti-neoplastic activity, even if it has not been widely studied and the regarding data are discordant, seems to result prevalently in tumour stabilisation.A few patients who fail to respond or cease to respond to standard SST analogues treatment seem to have a response to higher doses of these drugs.The use of higher doses of somatostatin analogues or the development of new subtype selective agonists and chimaeric somatostatin analogues, or pan-somatostatin will probably improve the clinical management of these patients.This review provides an update on the use of somatostatin analogues in the management of GEP NETs and discusses novel clinical strategies based on SSTR 2 gene transfer therapy.

Prognostic role of vascular endothelial growth factor in hepatocellular carcinoma: systematic review and meta-analysis

Hepatocellular carcinoma (HCC) is a highly vascular tumour that expresses vascular endothelial growth factor (VEGF). Various studies have evaluated the prognostic value of VEGF levels in HCC. Its overall test performance remains unclear, however. The aim was to perform a systematic review and meta-analysis of prognostic cohort studies evaluating the use of VEGF as a predictor of survival in patients with treated HCC. Eligible studies were identified through multiple search strategies. Studies were assessed for quality using the Newcastle–Ottawa Tool. Data were collected comparing disease-free and overall survival in patients with high VEGF levels as compared to those with low levels. Studies were pooled and summary hazard ratios were calculated. A total of 16 studies were included for meta-analysis (8 for tissue and 8 for serum). Methodological analysis indicated a trend for higher study quality with serum studies as compared to tissue-based investigations. Four distinct groups were pooled for analysis: tissue overall survival (n=251), tissue disease-free survival (n=413), serum overall survival (n=579), and serum disease-free survival (n=439). High tissue VEGF levels predicted poor overall (HR=2.15, 95% CI: 1.26–3.68) and disease-free (HR=1.69, 95% CI: 1.23–2.33) survival. Similarly, high serum VEGF levels predicted poor overall (HR=2.35, 95% CI: 1.80–3.07) and disease-free (HR=2.36, 95% CI 1.76–3.16) survival. A high degree of inter-study consistency was present in three of four groups analysed. Tissue and serum VEGF levels appear to have significant predictive ability for estimating overall survival in HCC and may be useful for defining prognosis in HCC.

mTOR inhibitors for hepatocellular cancer: a forward-moving target

mTOR is a central regulator of cell growth and angiogenesis. The mTOR pathway is activated in 40-50% of patients with hepatocellular cancer (HCC). In different models (i.e., hepatoma cell lines and implanted HCC tumors in rats), mTOR inhibitors (mTORIs) were effective in reducing cell growth and tumor vascularity. Synergistic effects were observed for mTORIs and chemotherapeutic agents in these studies, while other combinations involving mTORIs and inhibitors of growth hormones and angiogenesis are awaiting further clinical testing. A number of mTORIs are already clinically available (e.g., sirolimus, temsirolimus and everolimus), sharing similiar pharmacokinetic parameters (except for absorption) and side effects. Clinical data are, as yet, only preliminary and are mainly derived from retrospective studies in patients who underwent liver transplantation for HCC. Those patients had received sirolimus thereafter for immunosuppression, and a much lower rate of tumor recurrence than with calcineurin inhibitors alone was noted. Current prospective trials for treatment of advanced HCC include mTORIs alone or in combination with either transarterial chemoembolization or other systemic drugs, and will be discussed in detail in this review.

Impact of different anticancer regimens on biomarkers of angiogenesis in patients with advanced hepatocellular cancer

OBJECTIVE

Advanced hepatocellular cancer (HCC) is a highly vascularised tumor with limited treatment options. We wanted to evaluate the impact of different treatments on systemic biomarkers linked to angiogenesis.

METHODS

Two subsequent prospective, randomised, phase-I/II trials in patients with advanced HCC were performed. A total of 38 patients was randomised to a total of 4 regimens consisting of 3 cycles of 4 weeks each: Trial 1 included group 1 receiving octreotide 30 mg im on day 1, and group 2 octreotide 30 mg on day 1 plus Imatinib 400 mg po daily; Trial 2 included group 3 with oxaliplatin on day 1 (60 mg-90 mg/m(2)), and group 4 with oxaliplatin on day 1, 8, 15 (20 mg-30 mg/m(2)) in combination with octreotide 30 mg on day 1 plus imatinib 400 mg po daily. Primary outcome measure was the relative changes in plasma biomarkers over time.

RESULTS

Time-to-progression and overall survival was not different between the the two study trials. Within group 1-4, the mean relative increase from baseline to week 12 of treatment was 17, 18, 37, and 2% for s-E-selectin; -1, 90, 10, and -9% for VEGF-A; 18, 84, 141, and 74% for PDGF-BB, and 111, 142, 30, and 7% for serum AFP, respectively.

CONCLUSIONS

The increase of plasma levels for s-E-selectin and PDGF-BB seen in patients receiving chemotherapy alone may reflect activation of angiogenesis. In contrast, low-dose metronomic chemotherapy in combination with anti-angiogenic drugs seems to correlate with the least increase in biomarkers. Imatinib-octreotide temporarily leads to a decrease in PDGF-BB, whereas octreotide alone had no effect on PDGF-BB plasma levels.

Imatinib for hepatocellular cancer--focus on pharmacokinetic/pharmacodynamic modelling and liver function

The effects of imatinib are partly mediated by the inhibition of platelet-derived growth factor (PDGF), which is highly expressed in the liver. In this phase-I/II trial pharmacokinetic parameters of imatinib given for hepatocellular cancer were similar to those previously derived from CML patients. The AUC of N-desmethyl-imatinib depended on liver function; the metabolism of imatinib was otherwise comparable to other populations. During short-termed imatinib treatment (4 weeks, 400 mg/d), plasma PDGF significantly decreased. The AUC of N-desmethyl-imatinib could best be attributed to the pharmacodynamic effect of PDGF inhibition (r=-0.679 [95% CI: -0.917 to -0.0868], p=0.031).

Association of gankyrin protein expression with early clinical stages and insulin-like growth factor-binding protein 5 expression in human hepatocellular carcinoma

Gankyrin (also known as PSMD10) is a liver oncoprotein that interacts with multiple proteins including MDM2 and accelerates degradation of the tumor suppressors p53 and Rb. We produced a monoclonal anti-gankyrin antibody and immunohistochemically assessed the clinicopathological significance of gankyrin overexpression in 43 specimens of human hepatocellular carcinoma (HCC). Specific cytoplasmic staining for gankyrin was observed in 62.8% (27/43) of HCCs, which was significantly associated with low TNM stage (P = 0.004), no capsular invasion (P = 0.018), no portal venous invasion (P = 0.008), and no intrahepatic metastasis (P = 0.012). The cumulative survival rate of patients with gankyrin-positive HCC was significantly higher than that with gankyrin-negative HCC (P = 0.037). p53 and MDM2 were positively stained by antibodies in 30.2% and 23.3%, respectively, of HCCs, but neither was inversely associated with gankyrin expression. In the Huh-7 human HCC cell line, overexpression of gankyrin up-regulated expression of insulin-like growth factor binding protein 5 (IGFBP-5), whereas suppression of gankyrin expression by siRNA down-regulated it. Supression of IGFBP-5 expression inhibited proliferation of Huh-7 cells as well as U-2 OS osteosarcoma cells. In HCC specimens, positive staining for IGFBP-5 was observed by immunohistochemistry in 41.9% (18/43), and the level of expression was significantly correlated with that of gankyrin (rho = 0.629, P < 0.001).

CONCLUSION

These results suggest that gankyrin plays an oncogenic role(s) mainly at the early stages of human hepatocarcinogenesis, and that IGFBP-5 inducible by gankyrin overexpression may be involved in it.