Statins and cancer: A systematic review and meta-analysis

The addition of pravastatin to chemotherapy in advanced gastric carcinoma: a randomised phase II trial

PURPOSE

Statins have for long been considered to play a potential role in anticancer treatment based upon their ability to inhibit the mevalonate synthesis pathway. This randomised phase II trial compared the efficacy and safety of pravastatin added to epirubicin, cisplatin and capecitabine (ECC versus ECC+P) in patients with advanced gastric carcinoma.

METHODS

Patients were randomised to receive up to six cycles of 3-weekly ECC with or without pravastatin (40 mg, once daily from day 1 of the first cycle until day 21 of the last cycle). Primary end-point was progression-free rate at 6 months (PFR(6 months)). Secondary end-points were response rate (RR), progression-free survival (PFS), overall survival (OS) and safety. For early termination in case of futility, a two-stage design was applied (P(0) = 50%; P(1) = 70%; α = 0.05; β = 0.10).

RESULTS

Thirty patients were enrolled. PFR(6 months) was 6/14 patients (42.8%) in the ECC+P arm, and 7/15 patients (46.7%) in the control arm, and therefore the study was terminated after the first stage. In the ECC and ECC+P arm, RR was 7/15 (46.7%) and 5/15 (33.3%), median PFS was 5 and 6 months and median OS was 6 and 8 months, respectively. Toxicity data showed no significant differences, although there was a trend towards more gastrointestinal side-effects such as diarrhoea and stomatitis in the ECC+P arm.

CONCLUSION

In this randomised phase II trial the addition of pravastatin to ECC did not improve outcome in patients with advanced gastric cancer. Therefore, further testing of this combination in a randomised phase III trial cannot be recommended.

Ezetimibe reverses the inhibitory effects of dietary cholesterol on mammary tumorigenesis in rats

There are concerns regarding increased cancer incidence in patients treated with ezetimibe, an inhibitor of the absorption of dietary cholesterol. Here we tested the hypothesis that ezetimibe will accelerate mammary tumorigenesis in rats. The drug was administered at a dose of 1 ppm in an AIN-93G diet that contained 0.3% cholesterol. This experimental diet and control diets that contained either no additions or cholesterol or ezetimibe only, were fed to groups of 30 Sprague-Dawley rats 3 days after they were treated with 50 mg/kg methylnitrosourea (MNU). All rats were euthanized 22 weeks after MNU administration. Tumor multiplicity was significantly smaller in rats fed cholesterol than those fed no cholesterol (1.84 +/- 0.42 vs. 3.86 +/- 0.86 respectively, P < 0.05), but was significantly greater in the cholesterol/ezetimibe group than the group fed only cholesterol (3.48 +/- 0.59 vs. 1.84 +/- 0.42 respectively, P < 0.04). The average weight of tumors/rat was also significantly larger in the cholesterol/ezetimibe group than those fed cholesterol alone (5.67 +/- 1.15 vs. 2.56 +/- 0.71 respectively, P < 0.04). As expected, ezetimibe prevented the cholesterol raising effect of the dietary cholesterol. These results show that ezetimibe reverses the inhibitory effect of dietary cholesterol on the development of rat mammary tumors.

Why statin therapy may increase the risk for posttransplantation squamous cell carcinoma

We suggest that surveillance for squamous cell cancer might be particularly useful for transplant patients receiving statin therapy. We recommend that development of non melanoma skin cancer should be specified as a secondary endpoint in future large endpoint statin trials, and suggest that in transplant patients the adverse effects of statin drugs may outweigh benefits, especially in women and the elderly, a subset of population in which even individuals at high risk for cardiovascular disease have shown no trend to net benefit from statins.

Statin use and cancer risk: a comprehensive review

IMPORTANCE OF THE FIELD

HMG-CoA inhibitors (statins), a class of drugs that reduce cholesterol, are used to manage and prevent coronary heart disease. They are among the most commonly prescribed drugs worldwide. Contrary to early concerns over the carcinogenicity of statins, a growing body of evidence suggests statins may in fact have a chemopreventive potential against cancer.

AREAS COVERED IN THIS REVIEW

In this paper, we review evidence on the association between statin use and cancer risk. Specifically, we report on clinical trials and observational studies that measured all cancer or site-specific cancers of the breast, colorectal, lung, prostate and reproductive organs associated with statin use.

WHAT THE READER WILL GAIN

An understanding of the evidence, including strengths and limitations, to support an association between statins and cancer. Information on the current state of the field and future directions are also discussed.

TAKE HOME MESSAGE

Few strong or consistent associations between statins and cancer incidence overall or for any of the sites reviewed were detected. Data for any effects of statins on cancer prognosis and secondary prevention are lacking; with the exception of consistent evidence that statins are associated with reduced risk of advanced/aggressive prostate cancer. Statins appear safe in relation to cancer risk but any chemopreventive effect in humans remains to be established and should not be recommended outside the context of clinical trials. It is encouraging that numerous trials are ongoing. The prospect of reducing the incidence and burden of some of the most prevalent cancers with safe, affordable and tolerable medication that already reduces the risk of the leading cause of death and cardiovascular disease warrants further exploration in clinical trials and observational studies of prognosis and survival.

Statin-induced autophagy by inhibition of geranylgeranyl biosynthesis in prostate cancer PC3 cells

BACKGROUND

Autophagy is a cellular process of degradation of macromolecules and organelles and activated under nutritional stress. Statins are a class of inhibitors of 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a key enzyme in synthesis of cholesterol. Epidemiological studies have shown that statin use decreases the incidence of advanced prostate cancer. We explored the idea that treatment of atorvastatin, a commonly prescribed statin for treatment of hypercholesterolemia, induces autophagy in prostate cancer cells.

METHODS

The atorvastatin-induced autophagic process in prostate cancer PC3 cells was determined by detection of cellular level of LC3-II, an autophagosomal marker, via immunoblotting and immunofluorescent staining.

RESULTS

Atorvastatin treatment of PC3 cells for 40 hrs increased expression of LC3-II by more than 10 fold in a dose-dependent manner. Treatment of the cells with pepstatin A and E64-d, the autophagic protease inhibitors, dramatically increased atorvastatin-dependent LC3-II expression level, suggesting that atorvastatin induces autophagic flux. In addition, atorvastatin treatment caused rapid death of PC3 cells. Atorvastatin-induced autophagy and rapid cell death were reversed by addition of geranylgeraniol, not farnesol, into culture medium, indicating that atorvastatin-mediated inhibition of geranylgeranyl biosynthesis causes autophagy and cell death. Furthermore, atorvastatin did not induce autophagy or cell death in normal prostate RWPE1 cells, and induced only a minor autophagic response in AR-positive prostate cancer LNCaP cells.

CONCLUSIONS

Our studies demonstrate that statins induce autophagy and autophagy-associated cell death in PC3 cells, likely through inhibition of geranylgeranylation, and suggest that autophagic response to statins may partially underlie the protective effects of statins on prostate cancer progression. Importantly, these findings highlight additional mechanisms by which statins might be used for prostate cancer therapy.

Statin treatment and mortality in bacterial infections--a systematic review and meta-analysis

BACKGROUND

Several studies have reported improved survival in severe bacterial infections among statin treated patients. In addition, statins have been ascribed beneficial anti-inflammatory effects. The aim of this study was to evaluate the effect of statin-treatment on mortality in patients with bacterial infections, by means of a systematic review and a meta-analysis.

METHODOLOGY AND PRINCIPAL FINDINGS

Studies investigating the association between statin use and mortality in patients with bacterial disease were identified in a systematic literature review and a meta-analysis was performed to calculate the overall odds ratio of mortality in statin users. The literature search identified 947 citations from which 40 relevant studies were extracted. In all, 15 studies comprising 113,910 patients were included in the final analysis. Statin use was associated with a significantly (p<0.0001) reduced mortality in patients suffering from bacterial infections (OR 0.52, 95% CI 0.42-0.66). However, all studies included were of observational design and funnel plot analyses indicated influence by a possible publication bias (Egger's bias test p<0.05). When a precision estimate test was used to adjust for publication bias the effect of statin treatment was no longer significant, with an OR of 0.79 (95% CI 0.58-1.07).

CONCLUSION/SIGNIFICANCE

According to the meta-analysis of observational studies presented here, patients on statin therapy seem to have a better outcome in bacterial infections. However, the association did not reach statistical significance after adjustment for apparent publication bias. Thus, there is a great need for randomised controlled trials investigating the possible beneficial effect of statins in bacterial infections.

Pravastatin use and cancer risk: a meta-analysis of individual patient data from long-term prospective controlled trials in Japan

PURPOSE

To assess the influence of pravastatin therapy on cancer morbidity and mortality by a meta-analysis of individual patient data (IPD) from three independent Japanese large-scale clinical trials.

METHODS

We conducted a meta-analysis of IPD collected from three large-scale prospective studies, the Management of Elevated Cholesterol in the Primary Prevention Group of Adult Japanese (MEGA) Study, Kyushu Lipid Intervention Study (KLIS), and Hokuriku Lipid Coronary Heart Disease Study-Pravastatin Atherosclerosis Trial (Holicos-PAT), which compared cardiovascular outcomes with pravastatin therapy and non-statin therapy in Japanese patients with hypercholesterolemia over a follow-up period of >or=4 years. The incidence of cancer or cancer death in the pravastatin and non-statin therapy groups was compared by multivariate Cox proportional hazard models stratified by trial. Subgroup analyses by sex and age were also conducted using the same methods.

RESULTS

In a total of 13 724 patients (mean age, 58 years; women, 48%) included in the analyses, pravastatin was not associated with an increased risk of developing cancer (hazard ratio [HR], 0.99; 95% confidence interval [95%CI], 0.81-1.19). Similarly, pravastatin therapy did not statistically affect cancer death (HR, 0.86; 95%CI, 0.61-1.21). Moreover, in subgroups analyses, no influence was observed on cancer incidence or death in relation to sex and age.

CONCLUSION

Pravastatin did not increase the rate of cancer incidence or cancer death in a large population of Japanese patients followed for >70,000 patient-years.

Basic Science Review: Statin Therapy-Part I: The Pleiotropic Effects of Statins in Cardiovascular Disease

3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA-reductase) inhibitors, otherwise known as statins, are currently the medical treatment of choice for hypercholesterolemia. Hypercholesterolemia is a known risk factor for cardiovascular disease, and statin therapy has led to a significant reduction in morbidity and mortality from adverse cardiac events, stroke, and peripheral arterial disease. In addition to achieving a therapeutic decrease in serum cholesterol levels, statin therapy appears to promote other effects that are independent of changes in serum cholesterol. These ‘‘pleiotropic’’ effects include attenuation of vascular inflammation, improved endothelial cell function, stabilization of atherosclerotic plaque, decreased vascular smooth muscle cell migration and proliferation, and inhibition of platelet aggregation. This article is part I of a 2-part review, and it focuses on the pleiotropic effects of statins at the cellular level.

Serum cholesterol level, use of a cholesterol-lowering drug, and breast cancer: results from the prospective E3N cohort

Metabolic syndrome, including low HDL cholesterol, has been associated with an increased breast cancer risk, whereas little is known of the relationship with total cholesterol. Cox proportional hazards regression models were performed to evaluate the association between self-reported total serum cholesterol, cholesterol-lowering drugs, and risk of breast cancer in 69 088 women from the French E3N cohort study. A total of 2932 cases of primary invasive breast cancer were reported during 12 years of follow-up. Compared with women with low/normal serum cholesterol (<6.6 mol/l), users of cholesterol-lowering drugs had a significantly decreased breast cancer risk [hazard ratio (HR): 0.79, 95% confidence interval (CI): 0.68, 0.93]. There was no variation in HRs according to the menopausal status. In strata defined by the hormone receptor status of the tumor, the risk reached statistical significance only for the estrogen-positive and progesterone-positive receptor subtype (HR: 0.64, 95% CI: 0.50, 0.82). A high cholesterol without cholesterol-lowering drug use was not associated with breast cancer risk (HR: 0.99, 95% CI: 0.85, 1.15) in the entire population. Our result concerning cholesterol-lowering drugs is consistent with studies showing that hypolipidemic molecules are effective in inhibiting cancer cell growth proliferation. Further studies should investigate whether these findings apply to all classes of cholesterol-lowering drugs.

The role of oxysterol binding protein-related protein 5 in pancreatic cancer

The expression of oxysterol binding protein-related protein (ORP) 5 is related to invasion and a poor prognosis in pancreatic cancer patients. ORP5 induced the expression of sterol response element binding protein (SREBP) 2 and activated the downstream gene of sterol response element. ChIP using SREBP2 antibody revealed that histone deacetylase 5 (HDAC5) was one of the downstream genes of SREBP2. The effect of HMG-CoA reductase inhibitors (statins) were analyzed according to the expression level of ORP5. The invasion rate and growth was suppressed in cells that strongly expressed ORP5 in a time- and dose-dependent manner, but had less effect in cells weakly expressing ORP5, suggesting that when the potential of invasion and growth relies on the cholesterol synthesis pathway, it becomes sensitive to HMG-CoA reductase inhibitor. Furthermore, HDAC inhibitor, tricostatin A, induced the expression of phosphatase and tensin homolog as well when ORP5 was suppressed or the cells were treated with statin. Treatment with both statin and tricostatin A showed a synergistic antitumor effect in cells that highly expressed ORP5. Therefore, in some pancreatic cancers, continuous ORP5 expression enhances the cholesterol synthesis pathway and this signal transduction regulates phosphatase and tensin homolog through HDAC5 expression. This is the first report to detail how the signal transduction of cholesterol synthesis is related to cancer invasion and why statins can suppress invasion and growth.

Cardiotoxicity of anticancer drugs: the need for cardio-oncology and cardio-oncological prevention

Due to the aging of the populations of developed countries and a common occurrence of risk factors, it is increasingly probable that a patient may have both cancer and cardiovascular disease. In addition, cytotoxic agents and targeted therapies used to treat cancer, including classic chemotherapeutic agents, monoclonal antibodies that target tyrosine kinase receptors, small molecule tyrosine kinase inhibitors, and even antiangiogenic drugs and chemoprevention agents such as cyclooxygenase-2 inhibitors, all affect the cardiovascular system. One of the reasons is that many agents reach targets in the microenvironment and do not affect only the tumor. Combination therapy often amplifies cardiotoxicity, and radiotherapy can also cause heart problems, particularly when combined with chemotherapy. In the past, cardiotoxic risk was less evident, but it is increasingly an issue, particularly with combination therapy and adjuvant therapy. Today's oncologists must be fully aware of cardiovascular risks to avoid or prevent adverse cardiovascular effects, and cardiologists must now be ready to assist oncologists by performing evaluations relevant to the choice of therapy. There is a need for cooperation between these two areas and for the development of a novel discipline, which could be termed cardio-oncology or onco-cardiology. Here, we summarize the potential cardiovascular toxicities for a range of cancer chemotherapeutic and chemopreventive agents and emphasize the importance of evaluating cardiovascular risk when patients enter into trials and the need to develop guidelines that include collateral effects on the cardiovascular system. We also discuss mechanistic pathways and describe several potential protective agents that could be administered to patients with occult or overt risk for cardiovascular complications.

Apolipoprotein e genotype, plasma cholesterol, and cancer: a Mendelian randomization study

Observational studies have shown an association between low plasma cholesterol levels and increased risk of cancer, whereas most randomized clinical trials involving cholesterol-lowering medications have not shown this association. Between 1997 and 2002, the authors assessed the association between plasma cholesterol levels and cancer risk, free from confounding and reverse causality, in a Mendelian randomization study using apolipoprotein E (ApoE) genotype. ApoE genotype, plasma cholesterol levels, and cancer incidence and mortality were measured during a 3-year follow-up period among 2,913 participants in the Prospective Study of Pravastatin in the Elderly at Risk. Subjects within the lowest third of plasma cholesterol level at baseline had increased risks of cancer incidence (hazard ratio (HR) = 1.90, 95% confidence interval (CI): 1.34, 2.70) and cancer mortality (HR = 2.03, 95% CI: 1.23, 3.34) relative to subjects within the highest third of plasma cholesterol. However, carriers of the ApoE2 genotype (n = 332), who had 9% lower plasma cholesterol levels than carriers of the ApoE4 genotype (n = 635), did not have increased risk of cancer incidence (HR = 0.86, 95% CI: 0.50, 1.47) or cancer mortality (HR = 0.70, 95% CI: 0.30, 1.60) compared with ApoE4 carriers. These findings suggest that low cholesterol levels are not causally related to increased cancer risk.

Incidence of cancer and statin usage--record linkage study

The consumption of statins (HMG-CoA reductase inhibitors) has been increasing, and a substantial part of the middle-aged and elderly population use them continuously. Because a large fraction of the population is exposed, even a small excess of risk with respect to cancer should be considered. We carried out a record-linkage study in Finland utilizing nationwide databases of reimbursed statin medication and cancer. The study population included all statin users in Finland who had purchased at least 1 prescription between 1996 and 2005 and who had no cancer diagnosis at the date of first purchase. A control population without statin usage was also included. Data consisted of 472,481 pairs of individuals that cumulated 4.2 million person years with an average of 8.8 years of follow-up. Fifty thousand two hundred ninety-four cancer cases were observed. Simvastatin and atorvastatin were the most used substances. The most frequent cancers were prostate, breast, lung, colon, and rectum cancer. In general, no association between the utilization of statins and cancer could be detected. In conclusion, this study adds large-scale, population-based results about the association between statin utilization and the incidence of cancer. We found neither beneficial nor harmful associations between the usage of statins and cancer.

Lipid-lowering drugs and risk for cancer

The suspicion that lipid-lowering drugs might increase the risk for cancer has been present for three decades and has been the reason for intense debate and several attempts to reanalyze data from clinical trials. Recently, the results of the Simvastatin and Ezetimibe in Aortic Stenosis study sparked new interest in this problem, as the intense lipid-lowering therapy seems to have increased the number of cancers compared with the control group. This article gives an overview of the clinical evidence from trials and observational studies. As of now, the evidence is inconclusive, but there does not appear to be a reason for serious concern with short-term therapy. Whether statins and other lipid-lowering drugs will increase the risk of cancer when used over several decades is at present unknown.

Is statin use associated with prostate cancer aggressiveness?

OBJECTIVE

To further examine the association between statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) and pathological features in a large group of patients undergoing radical prostatectomy (RP), as epidemiological studies have suggested that statins, in addition to their beneficial cardiovascular effects, might reduce the risk of aggressive prostate cancer.

PATIENTS AND METHODS

From 2003 to 2009, 1351 men with data on preoperative statin use had RP by one surgeon. The clinical and pathological tumour features were compared between 504 users of statins and 847 who were not users.

RESULTS

Statin users were significantly older and had a higher mean body mass index than non-users. The preoperative serum prostate-specific antigen levels, tumour volume and percentage of cancer in the RP specimen were significantly lower in patients taking statins. Overall, statin users had a proportionately lower rate of adverse tumour pathology features, including a significantly lower risk of positive (cancerous) surgical margins.

CONCLUSION

Our results suggest that the use of statins might be associated with more favourable pathological features at RP. The long-term disease-specific outcomes and the underlying link between statins and prostate cancer require further investigation.

Statins May Reduce Breast Cancer Risk, Particularly Hormone Receptor-Negative Disease

Estrogen and progesterone receptor-negative breast cancer disproportionately affects young women and African Americans, has a poor prognosis, and lacks an effective chemoprevention agent. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, known as "statins," are appealing candidate agents for breast cancer chemoprevention because of their demonstrated safety after decades of widespread use. In preclinical studies, statins inhibit multiple cancer-associated pathways in both hormone receptor (HR)-negative and HR-positive cell lines. Epidemiologic studies of statins and breast cancer show inconsistent results, with some suggesting a reduction in HR-negative breast cancer incidence in lipophilic statin users. However, large meta-analyses show no association between statin use and overall risk of breast cancer, although most did not evaluate tumor HR status. Multiple phase 1 and 2 prevention studies of statins for breast cancer risk reduction are ongoing. If results are promising, they may justify a randomized trial of statins for breast cancer chemoprevention, with a focus on HR-negative disease.

Pitavastatin fails to lower serum lipid levels or inhibit gastric carcinogenesis in helicobacter pylori-infected rodent models

Statins are commonly used lipid-lowering drugs that reduce the risk of cardiovascular morbidity and mortality. Although recent studies have pointed to chemopreventive effects of statins against various cancers, their efficacy for gastric cancer is unclear. Here, we examined the effects of pitavastatin, a lipophilic statin, on Helicobacter pylori (H. pylori)-associated stomach carcinogenesis and gastritis using Mongolian gerbil and mouse models. The animals were allocated to H. pylori + N-methyl-N-nitrosourea administration (gerbils, 52 weeks) or H. pylori infection alone groups (gerbils and mice, 12 weeks). After H. pylori infection, they were fed basal diets containing 0 to 10 ppm of pitavastatin. The incidences of H. pylori-associated gastric adenocarcinomas and degrees of chronic gastritis were not decreased by pitavastatin compared with those of control values. Expression of interleukin-1beta and tumor necrosis factor-alpha mRNAs in the pyloric mucosa was markedly up-regulated in pitavastatin-treated animals. Furthermore, in the H. pylori-infected groups, serum total cholesterol, triglyceride, and low-density lipoprotein levels were significantly increased by pitavastatin treatment, contrary to expectation. In the short-term study, H. pylori-infected gerbils and mice also showed significant up-regulation of serum triglyceride levels by pitavastatin, whereas total cholesterol was markedly reduced and low-density lipoprotein exhibited a tendency for decrease in noninfected animals. These findings indicate pitavastatin to be ineffective for suppressing gastritis and chemoprevention of gastric carcinogenesis in H. pylori-infected gerbils. Our serologic results also suggest that the H. pylori infection and consequent severe chronic gastritis interfere with the cholesterol-lowering effects of pitavastatin.

Lipophilic but not hydrophilic statins selectively induce cell death in gynaecological cancers expressing high levels of HMGCoA reductase

Recent reports have suggested that statins induce cell death in certain epithelial cancers and that patients taking statins to reduce cholesterol levels possess lower cancer incidence. However, little is known about the mechanisms of action of different statins or the effects of these statins in gynaecological malignancies. The apoptotic potential of two lipophilic statins (lovastatin and simvastatin) and one hydrophilic statin (pravastatin) was assessed in cancer cell lines (ovarian, endometrial and cervical) and primary cultured cancerous and normal tissues. Cell viability was studied by MTS assays and apoptosis was confirmed by Western blotting of PARP and flow cytometry. The expressions of key apoptotic cascade proteins were analysed. Our results demonstrate that both lovastatin and simvastatin, but not pravastatin, selectively induced cell death in dose- and time-dependent manner in ovarian, endometrial and cervical cancers. Little or no toxicity was observed with any statin on normal cells. Lipophilic statins induced activation of caspase-8 and -9; BID cleavage, cytochrome C release and PARP cleavage. Statin-sensitive cancers expressed high levels of HMG-CoA reductase compared with resistant cultures. The effect of lipophilic statins was dependent on inhibition of enzymatic activity of HMG-CoA reductase since mevalonate pre-incubation almost completely abrogated the apoptotic effect. Moreover, the apoptotic effect involved the inhibition of synthesis of geranylgeranyl pyrophosphate rather than farnesyl pyrophosphate. In conclusion, lipophilic but not hydrophilic statins induce cell death through activation of extrinsic and intrinsic apoptotic cascades in cancerous cells from the human female genital tract, which express high levels of HMG-CoA reductase. These results promote further investigation in the use of lipophilic statins as anticancer agents in gynaecological malignancies.

Does statin use affect the risk of developing prostate cancer?

This commentary discusses the findings of Agalliu and colleagues, who performed a population-based, case-control study on the association between statin drugs and prostate cancer risk. Consistent with recent studies, statins were not associated with overall prostate cancer risk, but users had a possible lower risk of advanced disease. Obese men taking a statin had a higher risk of prostate cancer than those not taking a statin; however, a previously conducted, large, prospective, cohort study did not observe this association. This unexpected finding by Agalliu et al. could be a chance result, or could have arisen because of complex bias. Although statins might favorably affect men's prostate health, evidence is too limited to recommend statin use for the prevention of advanced prostate cancer. Consideration of the harms and benefits when prescribing a statin for vascular indications, including in obese men, should not presently include prostate cancer risk.

Rho GTPases in hepatocellular carcinoma

Rho GTPases are major regulators of signal transduction pathways and play key roles in processes including actin dynamics, cell cycle progression, cell survival and gene expression, whose deregulation may lead to tumorigenesis. A growing number of in vitro and in vivo studies using tumor-derived cell lines, primary tumors and animal cancer models strongly suggest that altered Rho GTPase signaling plays an important role in the initiation as well as in the progression of hepatocellular carcinoma (HCC), one of the deadliest human cancers in the world. These alterations can occur at the level of the GTPases themselves or of one of their regulators or effectors. The participation into the tumorigenic process can occur either through the over-expression of one of these components which presents an oncogenic activity as illustrated with RhoA and C or through the attenuation of the expression of a component presenting tumor suppressor activity as for Cdc42 or the RhoGAP, DLC-1. Consequently, these observations reflect the heterogeneity and the complexity of liver carcinogenesis. Recently, pharmacological approaches targeting Rho GTPase signaling have been used in HCC-derived models with relative success but remain to be validated in more physiologically relevant systems. Therefore, therapeutic approaches targeting Rho GTPase signaling may provide a novel alternative for anti-HCC therapy.

Prognostic impact of tumour-specific HMG-CoA reductase expression in primary breast cancer

Introduction

We have previously reported that tumour-specific expression of the rate-limiting enzyme, 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMG-CoAR), in the mevalonate pathway is associated with more favourable tumour parameters in breast cancer. In the present study, we examined the prognostic value of HMG-CoAR expression in a large cohort of primary breast cancer patients with long-term follow up.

Methods

The expression of HMG-CoAR was assessed by immunohistochemistry on tissue microarrays with tumour specimens from 498 consecutive cases of breast cancer with a median follow-up of 128 months. Kaplan Meier analysis and Cox proportional hazards modelling were used to estimate the rate of recurrence-free survival (RFS) and breast cancer specific survival (BCSS).

Results

In line with our previous findings, tumour-specific HMG-CoAR expression was associated with low grade (p < 0.001), small size (p = 0.007), oestrogen receptor (ER) positive (p = 0.01), low Ki-67 (p = 0.02) tumours. Patients with tumours expressing HMG-CoAR had a significantly prolonged RFS, even when adjusted for established prognostic factors (relative risk [RR] = 0.60, 95% confidence interval [CI] 0.40 to 0.92; p = 0.02). In ER-negative tumours, however, there was a trend, that was not significantly significant, towards a shorter RFS in HMG-CoAR expressing tumours.

Conclusions

HMG-CoAR expression is an independent predictor of a prolonged RFS in primary breast cancer. This may, however, not be true for ER-negative tumours. Further studies are needed to shed light on the value of HMG-CoAR expression as a surrogate marker of response to statin treatment, especially with respect to hormone receptor status.