Colorectal cancer chemoprevention by 2 β‐cyclodextrin inclusion compounds of auraptene and 4′‐geranyloxyferulic acid

The inhibitory effects of novel prodrugs, inclusion complexes of 3‐(4′‐geranyloxy‐3′‐methoxyphenyl)‐2‐trans propenoic acid (GOFA) and auraptene (AUR) with β‐cyclodextrin (CD), on colon carcinogenesis were investigated using an azoxymethane (AOM)/dextran sodium sulfate (DSS) model. Male CD‐1 (ICR) mice initiated with a single intraperitoneal injection of AOM (10 mg/kg body weight) were promoted by the addition of 1.5% (w/v) DSS to their drinking water for 7 days. They were then given a basal diet containing 2 dose levels (100 and 500 ppm) of GOFA/β‐CD or AUR/β‐CD for 15 weeks. At Week 18, the development of colonic adenocarcinoma was significantly inhibited by feeding with GOFA/β‐CD at dose levels of 100 ppm (63% reduction in multiplicity, p < 0.05) and 500 ppm (83% reduction in the multiplicity, p < 0.001), when compared with the AOM/DSS group (multiplicity: 3.36 ± 3.34). In addition, feeding with 100 and 500 ppm (p < 0.01) of AUR/β‐CD suppressed the development of colonic adenocarcinomas. The dietary administration with GOFA/β‐CD and AUR/β‐CD inhibited colonic inflammation and also modulated proliferation, apoptosis and the expression of several proinflammatory cytokines, such as nuclear factor‐kappaB, tumor necrosis factor‐α, Stat3, NF‐E2‐related factor 2, interleukin (IL)‐6 and IL‐1β, which were induced in the adenocarcinomas. Our findings indicate that GOFA/β‐CD and AUR/β‐CD, especially GOFA/β‐CD, are therefore able to inhibit colitis‐related colon carcinogenesis by modulating inflammation, proliferation and the expression of proinflammatory cytokines in mice.     

Crucial involvement of the CCL3‐CCR5 axis‐mediated fibroblast accumulation in colitis‐associated carcinogenesis in mice

Patients with inflammatory bowel diseases often develop colon carcinoma. Combined treatment of azoxymethane (AOM) and dextran sulfate sodium (DSS) recapitulates colitis‐associated cancer in mice. AOM/DSS‐induced tumor formation was reduced in CCL3‐ or its specific receptor, CCR5‐deficient mice despite the presence of a massive infiltration of inflammatory cells. However, AOM/DSS‐induced type I collagen‐positive fibroblast accumulation in the colon was reduced in CCL3‐ or CCR5‐deficient mice. This was associated with depressed expression of heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF), which is expressed mainly by fibroblasts. Moreover in vitro, CCL3 induced fibroblasts to proliferate and to enhance HB‐EGF expression. Furthermore, CCR5 blockade reduced tumor formation together with reduced fibroblast accumulation and HB‐EGF expression, even when administered after the development of multiple colon tumors. Thus, CCL3‐CCR5‐mediated fibroblast accumulation may be required, in addition to leukocyte infiltration, to induce full‐blown colitis‐associated carcinogenesis. Our studies shed light on a therapeutic potential of CCR5 antagonist for patients with colitis‐associated cancer.     

Dietary‐feeding of grape seed extract prevents azoxymethane‐induced colonic aberrant crypt foci formation in fischer 344 rats

Chemoprevention by dietary agents/supplements has emerged as a novel approach to control various malignancies, including colorectal cancer (CRC). This study assessed dietary grape seed extract (GSE) effectiveness in preventing azoxymethane (AOM)‐induced aberrant crypt foci (ACF) formation and associated mechanisms in Fischer 344 rats. Six‐week‐old rats were injected with AOM, and fed control diet or the one supplemented with 0.25% or 0.5% (w/w) GSE in pre‐ and post‐AOM or only post‐AOM experimental protocols. At 16 wk of age, rats were sacrificed and colons were evaluated for ACF formation followed by cell proliferation, apoptosis, and molecular analyses by immunohistochemistry. GSE‐feeding caused strong chemopreventive efficacy against AOM‐induced ACF formation in terms of up to 60% (P < 0.001) reduction in number of ACF and 66% (P < 0.001) reduction in crypt multiplicity. Mechanistic studies showed that GSE‐feeding inhibited AOM‐induced cell proliferation but enhanced apoptosis in colon including ACF, together with a strong decrease in cyclin D1, COX‐2, iNOS, and survivin levels. Additional studies showed that GSE‐feeding also decreased AOM‐caused increase in β‐catenin and NF‐κB levels in colon tissues. Compared to control animals, GSE alone treatment did not show any considerable change in these biological and molecular events in colon, and was nontoxic. Together, these findings show the chemopreventive efficacy of GSE against the early steps of colon carcinogenesis in rats via likely targeting of β‐catenin and NF‐κB signaling, and suggest its potential usefulness for the prevention of human CRC. © 2010 Wiley‐Liss, Inc.     

Eicosapentaenoic acid free fatty acid prevents and suppresses colonic neoplasia in colitis‐associated colorectal cancer acting on Notch signaling and gut microbiota

Inflammatory bowel diseases are associated with increased risk of developing colitis‐associated colorectal cancer (CAC). Epidemiological data show that the consumption of ω‐3 polyunsaturated fatty acids (ω‐3 PUFAs) decreases the risk of sporadic colorectal cancer (CRC). Importantly, recent data have shown that eicosapentaenoic acid‐free fatty acid (EPA‐FFA) reduces polyp formation and growth in models of familial adenomatous polyposis. However, the effects of dietary EPA‐FFA are unknown in CAC. We tested the effectiveness of substituting EPA‐FFA, for other dietary fats, in preventing inflammation and cancer in the AOM‐DSS model of CAC. The AOM‐DSS protocols were designed to evaluate the effect of EPA‐FFA on both initiation and promotion of carcinogenesis. We found that EPA‐FFA diet strongly decreased tumor multiplicity, incidence and maximum tumor size in the promotion and initiation arms. Moreover EPA–FFA, in particular in the initiation arm, led to reduced cell proliferation and nuclear β‐catenin expression, whilst it increased apoptosis. In both arms, EPA‐FFA treatment led to increased membrane switch from ω‐6 to ω‐3 PUFAs and a concomitant reduction in PGE₂ production. We observed no significant changes in intestinal inflammation between EPA‐FFA treated arms and AOM‐DSS controls. Importantly, we found that EPA‐FFA treatment restored the loss of Notch signaling found in the AOM‐DSS control and resulted in the enrichment of Lactobacillus species in the gut microbiota. Taken together, our data suggest that EPA‐FFA is an excellent candidate for CRC chemoprevention in CAC.     

3,3′‐diindolylmethane suppresses 12‐O‐tetradecanoylphorbol‐13‐acetate‐induced inflammation and tumor promotion in mouse skin via the downregulation of inflammatory mediators

3,3′‐Diindolylmethane (DIM) is a major acid‐condensation product of indole‐3‐carbinol and is present in cruciferous vegetables. In this study, we evaluated the effects of DIM on antiinflammatory and antitumor promotion activity in mouse skin and explored the relevant mechanisms. When 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) was applied topically to the mouse ear to induce inflammation, DIM pretreatment effectively inhibited TPA‐induced ear edema formation. To evaluate the mechanisms underlying DIM's antiinflammatory effects, DIM was topically treated to the shaved backs of mice 30 min before TPA treatment. DIM inhibited the TPA‐induced increases in the expression of cyclooxygenase (COX)‐2, inducible nitric oxide synthase (iNOS), chemokine (C‐X‐C motif) ligand (CXCL) 5, and interleukin (IL)‐6 in mouse skin. DIM also inhibited nuclear factor‐kappa B (NF‐κB)'s DNA binding activity, the nuclear translocation of p65, and the degradation of inhibitor of κB (IκB) α in TPA‐stimulated mouse skin. Furthermore, DIM reduced TPA‐induced increases in the activity of extracellular signal regulated protein kinase (ERK)‐1/2 and IκB kinase (IKK). When mouse skin papillomas were initiated via the topical application of 7,12‐dimethylbenz[α]anthracene (DMBA) and promoted with repeated topical applications of TPA, repeated topical applications of DIM prior to each TPA treatment significantly suppressed the incidence and multiplicity of the papillomas. DIM also reduced the expression of COX‐2 and iNOS, ERK phosphorylation, and the nuclear translocation of p65 in papillomas. Collectively, these results show that DIM exerts antiinflammatory and chemopreventive effects in mouse skin via the downregulation of COX‐2, iNOS, CXCL5, and IL‐6 expression, which may be mediated by reductions in NF‐κB activation. © 2010 Wiley‐Liss, Inc.     

Prediagnostic plasma IGFBP‐1, IGF‐1 and risk of prostate cancer

Insulin‐like growth factor (IGF)?1 is associated with a higher risk of prostate cancer. IGF‐binding protein (IGFBP)?1, a marker for insulin activity, also binds IGF‐1 and inhibits its action. Data on IGFBP‐1 and prostate cancer risk are sparse and whether the IGF and insulin axes interact to affect prostate cancer carcinogenesis is unknown. We evaluated the independent and joint influence of prediagnostic plasma levels of IGFBP‐1 (fasting) and IGF‐1 on risk of prostate cancer among 957 cases and 1,021 controls with fasting levels of IGFBP‐1 and 1,709 cases and 1,778 controls with IGF‐1 nested within the Health Professionals Follow‐up Study. Unconditional logistic regression adjusting for matching factors was used to estimate the odds ratio (OR) and 95% confidence interval (CI). Higher prediagnostic fasting IGFBP‐1 levels were associated with lower risk of prostate cancer (highest vs. lowest quartile OR = 0.67, 95% CI 0.52–0.86, p_trend = 0.003), which remained similar after adjusting for IGF‐1. Prediagnostic IGF‐1 was associated with increased risk of prostate cancer (highest vs. lowest quartile OR = 1.28, 95% CI = 1.05–1.56, p_trend = 0.01). The associations with each marker were primarily driven by lower‐grade and non‐advanced prostate cancer. Being low in IGFBP‐1 and high in IGF‐1 did not confer appreciable additional risk (p_interaction = 0.42). In summary, prediagnostic fasting IGFBP‐1 may influence prostate cancer carcinogenesis. Being low in IGFBP‐1 or high in IGF‐1 is sufficient to elevate the risk of prostate cancer.     

Mucin‐depleted foci show strong activation of inflammatory markers in 1,2‐dimethylhydrazine‐induced carcinogenesis and are promoted by the inflammatory agent sodium dextran sulfate

Mucin‐depleted foci (MDF), formed by dysplastic crypts devoid of mucins, have been identified in the colon of carcinogen‐treated rodents and in humans at high risk for colon cancer. The lack of the protective layer of mucus may cause inflammation which has been linked to colon carcinogenesis, therefore, the expression of markers such as cyclooxygenase‐2 (COX‐2), inducible nitric oxide synthase (i‐NOS) and macrophage infiltration was studied with immunohistochemistry (IH) in MDF harvested from F344 rats treated with the colon carcinogen 1,2‐dimethylhydrazine (DMH). The same determinations were performed in aberrant crypt foci (ACF) and, at a later time point, in tumours. A dramatic increase in COX‐2, i‐NOS and macrophage infiltration was observed in MDF but ACF showed a moderate increase compared with the paired normal mucosa. Tumours were positive for all the markers. RT‐PCR experiments demonstrated that i‐NOS RNA expression was increased in a set of MDF confirming the results obtained with immunohistochemistry. In an inflammation‐cancer experimental model [mice treated with azoxymethane (AOM) and dextran sodium sulphate (DSS)], we observed that DSS‐induced inflammation promoted MDF in a dose‐dependent manner, whereas ACF were not affected. In conclusion, we report here for the first time a strong activation of the inflammatory process in MDF, which may contribute to the further progression of MDF to tumours. © 2009 UICC     

Blockade of MK2 is protective in inflammation‐associated colorectal cancer development

Chronic inflammation is a risk factor for colorectal cancer. The MAPK‐activated protein kinase 2 (MK2) pathway controls multiple cellular processes including p38‐dependent inflammation. This is the first study to investigate the role of MK2 in development of colitis‐associated colon cancer (CAC). Herein, we demonstrate that MK2^?/? mice are highly resistant to neoplasm development when exposed to AOM/DSS, while wild type (WT) C57BL/6 develop multiple neoplasms with the same treatment. MK2‐specific cytokines IL‐1, IL‐6 and TNF‐α were substantially decreased in AOM/DSS treated MK2^?/? mouse colon tissues compared with WT mice, which coincided with a marked decrease in macrophage influx. Restoring MK2‐competent macrophages by injecting WT bone marrow derived macrophages into MK2^?/? mice led to partial restoration of inflammatory cytokine production with AOM/DSS treatment; however, macrophages were not sufficient to induce neoplasm development. These results indicate that MK2 functions as an inflammatory regulator to promote colonic neoplasm development and may be a potential target for CAC.     

Polymethoxyflavones prevent benzo[a]pyrene/dextran sodium sulfate‐induced colorectal carcinogenesis through modulating xenobiotic metabolism and ameliorate autophagic defect in ICR mice

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental carcinogenic pollutants and they have become an important issue in food contamination. Dietary intake of PAHs has been recognized as a major route of human exposure. However, the mechanisms behind dietary PAH‐induced colorectal cancer (CRC) remain unclear. Several studies have shown that polymethoxyflavones (PMFs) are effective in preventing carcinogen‐induced CRC or colitis. In this study, we investigated the preventive effect of PMFs on benzo[a]pyrene/dextran sulfate sodium (BaP/DSS)‐induced colorectal tumorigenesis in ICR mice. We found that PMFs significantly prevented BaP/DSS‐induced colorectal tumor formation. BaP mutagenic metabolite and DNA adducts were found to be reduced in colonic tissue in the PMFs‐treated groups through the modulation of BaP metabolism. At the molecular level, the results of RNA‐sequencing indicated that PMFs ameliorated BaP/DSS‐induced abnormal molecular mechanism change including activated inflammation, downregulated anti‐oxidation targets, and induced metastasis genes. The autophagic defect caused by BaP/DSS‐induced tumorigenesis was improved by pretreatment with PMFs. We found BaP/DSS‐induced CRC may be a Wnt/β‐catenin independent process. Additionally, consumption of PMFs extracts also altered the composition of gut microbiota and made it similar to that in the control group by increasing butyrate‐producing probiotics and decreasing CRC‐related bacteria. BaP in combination with DSS significantly induced colorectal tumorigenesis through induced DNA adduct formation, abnormal gene expression, and imbalanced gut microbiota composition. PMFs were a powerful preventive agent that suppressed BaP/DSS‐induced CRC via modulating multiple pathways as well as ameliorating autophagic defect. These results demonstrated for the first time the chemopreventive efficacy and comprehensive mechanisms of dietary PMFs for preventing BaP/DSS‐induced colorectal carcinogenesis.     

Suppressive effects of Moringa oleifera Lam pod against mouse colon carcinogenesis induced by azoxymethane and dextran sodium sulfate

Moringa oleifera Lam (horseradish tree; tender pod or fruits) is a major ingredient in Thai cuisine and has some medicinal properties. Previous studies have shown potentially antioxidant, antitumor promoter, anticlastogen and anticarcinogen activities both in vitro and in vivo. The present study was conducted to investigate chemopreventive effects on azoxymethane (AOM)-initiated and dextran sodium sulfate (DSS)-promoted colon carcinogenesis in mice. Male ICR mice were divided into 8 groups: Group 1 served as a negative control; Group 2 received AOM/DSS as a positive control; Groups 3-5 were fed boiled freeze-dried M. oleifera (bMO) at 1.5%, 3.0% and 6.0%, respectively supplemented in basal diets for 5 weeks; Groups 6-8 were fed with bMO diets at the designed doses above for 2 weeks prior to AOM, during and 1 week after DSS administration. At the end of the study, colon samples were processed for histopathological examination. PCNA indices, and iNOS and COX-2 expression were assessed by immunohistochemistry. The results demonstrated the incidences and multiplicities of tumors in Groups 6-8 to be decreased when compared to Group 2 in a dose dependent manner, but this was significant only in Group 8. The PCNA index was also significantly decreased in Group 8 whereas iNOS and COX-2 protein expression were significantly decreased in Groups 7 and 8. The findings suggest that M. oleifera Lam pod exerts suppressive effects in a colitis-related colon carcinogenesis model induced by AOM/DSS and could serve as a chemopreventive agent.     

A novel glycobiomarker,Wisteria floribunda agglutinin macrophage colony‐stimulating factor receptor,for predicting carcinogenesis of liver cirrhosis

Recently, we identified a novel liver fibrosis glycobiomarker, Wisteria floribunda agglutinin (WFA)‐reactive colony stimulating factor 1 receptor (WFA⁺‐CSF1R), using a glycoproteomics‐based strategy. The aim of this study was to assess the value of measuring WFA⁺‐CSF1R levels for the prognosis of carcinogenesis and outcome in liver cirrhosis (LC) patients with hepatitis C virus (HCV). WFA⁺‐CSF1R and Total‐CSF1R levels were measured in serum samples from 214 consecutive HCV‐infected patients to evaluate their impact on carcinogenesis and the survival of LC patients. Serum WFA⁺‐CSF1R levels were significantly higher in LC patients than chronic hepatitis (CH) patients (p < 0.001). The AUC of WFA⁺‐CSF1R for predicting overall survival, calculated by time‐dependent ROC analysis, was 0.691 and the HR (per 1‐SD increase) was 1.80 (95% CI, 1.23–2.62, p < 0.001). Furthermore, the survival rate of LC patients with high WFA⁺‐CSF1R levels (≥310 ng/ml) was significantly worse than those with lower levels (p < 0.01). The AUC of WFA⁺/total‐CSF1R percentage (WFA⁺‐CSF1R%) for predicting the cumulative carcinogenesis rate was 0.760, with an HR of 1.66 (95% CI 1.26–2.20, p < 0.001). In fact, the carcinogenesis rate was significantly higher in LC patients with a high WFA⁺‐CSF1R% (≥ 35%, p = 0.006). Assessing serum levels of WFA⁺‐CSF1R has diagnostic value for predicting carcinogenesis and the survival of LC patients.     

Atorvastatin inhibits pancreatic carcinogenesis and increases survival in LSL‐KrasG12D‐LSL‐Trp53R172H‐Pdx1‐Cre mice

There are several studies supporting the role of HMG‐CoA reductase inhibitors such as atorvastatin against carcinogenesis, in which inhibiting the generation of prenyl intermediates involved in protein prenylation plays the crucial role. Mutation of Kras gene is the most common genetic alteration in pancreatic cancer and the Ras protein requires prenylation for its membrane localization and activity. In the present study, the effectiveness of atorvastatin against pancreatic carcinogenesis and its effect on protein prenylation were determined using the LSL‐Kras^G12D‐LSL‐Trp53^R172H‐Pdx1‐Cre mouse model (called Pan^kras/p53 mice). Five‐week‐old Pan^kras/p53 mice were fed either an AIN93M diet or a diet supplemented with 100 ppm atorvastatin. Kaplan–Meier survival analysis with Log‐Rank test revealed a significant increase in survival in mice fed 100 ppm atorvastatin (171.9 ± 6.2 d) compared to the control mice (144.9 ± 8.4 d, P < 0.05). Histologic and immunohistochemical analysis showed that atorvastatin treatment resulted in a significant reduction in tumor volume and Ki‐67‐labeled cell proliferation. Mechanistic studies on primary pancreatic tumors and the cultured murine pancreatic carcinoma cells revealed that atorvastatin inhibited prenylation in several key proteins, including Kras protein and its activities, and similar effect was observed in pancreatic carcinoma cells treated with farnesyltransferase inhibitor R115777. Microarray assay on the global gene expression profile demonstrated that a total of 132 genes were significantly modulated by atorvastatin; and Waf1p21, cyp51A1, and soluble epoxide hydrolase were crucial atorvastatin‐targeted genes which involve in inflammation and carcinogenesis. This study indicates that atorvastatin has the potential to serve as a chemopreventive agent against pancreatic carcinogenesis. © 2012 Wiley Periodicals, Inc.     

Pitavastatin inhibits azoxymethane‐induced colonic preneoplastic lesions in C57BL/KsJ‐db/db obese mice

Obesity and related metabolic abnormalities are risk factors for colorectal cancer. A state of chronic inflammation and adipocytokine imbalance may play a role in colorectal carcinogenesis. Statins, which are commonly used for the treatment of hyperlipidemia, are known to possess anti‐inflammatory effects. Statins also exert chemopreventive properties against various cancers. The present study examined the effects of pitavastatin, a recently developed lipophilic statin, on the development of azoxymethane (AOM)‐initiated colonic premalignant lesions in C57BL/KsJ‐db/db (db/db) obese mice. Male db/db mice were administrated weekly subcutaneous injections of AOM (15 mg/kg body weight) for 4 weeks and then were subsequently fed a diet containing 1 ppm or 10 ppm pitavastatin for 8 weeks. Feeding with either dose of pitavastatin significantly reduced the number of colonic premalignant lesions, β‐catenin accumulated crypts, by inhibiting proliferation and the surrounding inflammation. Pitavastatin increased the serum levels of adiponectin while conversely decreasing the serum levels of total cholesterol, tumor necrosis factor‐α (TNF‐α), interleukin (IL)‐6, IL‐18, and leptin. Pitavastatin also caused a significant increase in the expression of phosphorylated form of the AMP‐activated kinase (AMPK) protein on the colonic mucosa of AOM‐treated mice. In addition, the expression levels of TNF‐α, IL‐6, IL‐18, and COX‐2 mRNAs on the colonic mucosa of AOM‐treated mice were decreased by treatment with this agent. These findings suggest that pitavastatin attenuates chronic inflammation and improves the imbalance of adipocytokines, both of which are caused by the presence of excess adipose tissues, thereby preventing the development of colonic premalignancies in an obesity‐related colon cancer model. Therefore, some types of statins, including pitavastatin, may be a useful chemoprevention modality for colon cancer in obese individuals. (Cancer Sci 2010)     

Troglitazone, a Ligand for Peroxisome Proliferator-activated Receptor γ Inhibits Chemically-induced Aberrant Crypt Foci in Rats

The biological roles of peroxisome proliferator-activated receptors (PPARs) in various diseases, including inflammation and cancer, have been highlighted recently. Although PPARγ ligand is suspected to play an important role in carcinogenesis, its effects on colon tumorigenesis remain undetermined. The present tune-course study was conducted to investigate possible modifying effects of a PPARγ ligand, troglitazone, on the development and growth of aberrant crypt foci (ACF), putative precursor lesions for colon carcinoma, induced by azoxymethane (AOM) or dextran sodium sulfate (DSS) in male F344 rats. Oral troglitazone (10 or 30 mg/kg body weight (b.w.)) significantly reduced AOM (two weekly subcutaneous injections, 20 mg/kg b.w.)-induced ACF. Treatment with troglitazone increased apoptosis and decreased polyamine content and ornithine decarboxylase (ODC) activity in the colonic mucosa of rats treated with AOM. Gastric gavage of troglitazone also inhibited colitis and ACF induced by DSS (1% in drinking water), in conjunction with increased apoptosis and reduced colonic mucosal polyamine level and ODC activity. Our results suggest that troglitazone, a synthetic PPARγ ligand, can inhibit the early stage of colon tumorigenesis with or without colitis.     

The PD‐1/PD‐L1 axis and human papilloma virus in patients with head and neck cancer after adjuvant chemoradiotherapy: A multicentre study of the German Cancer Consortium Radiation Oncology Group (DKTK‐ROG)

We examined the prognostic role of PD‐1+ and CD8+ tumor infiltrating lymphocytes (TILs), and PD‐L1+ cells in patients with squamous cell carcinoma of the head and neck (SCCHN) treated with surgery and postoperative chemoradiotherapy (CRT). FFPE samples from 161 patients were immunohistochemically stained for PD‐1, CD8 and PD‐L1. The immune marker expression was correlated with clinicopathologic characteristics, and overall survival (OS), local progression‐free survival (LPFS) and distant metastases free‐survival (DMFS), also in the context of HPV16 DNA/p16 status. The median follow‐up was 48 months (range: 4–100). The 2‐year‐OS was 84.1% for the entire cohort. High PD‐1 and PD‐L1 expression were more common in patients with positive HPV16 DNA (p < 0.001 and p = 0.008, respectively) and high infiltration by CD8+ TILs (p < 0.001 for both markers). High PD‐L1 expression correlated with superior OS (p = 0.025), LPFS (p = 0.047) and DMFS (p = 0.048) in multivariable analysis, whereas no significance could be demonstrated for PD‐1. Patients with CD8^high/PD‐L1^high expression had favorable outcome (p < 0.001 for all endpoints) compared to other groups. We validated the superior OS data on CD8^high/PD‐L1^high using the Cancer Genome Atlas TCGA dataset (n = 518; p = 0.032). High PD‐L1 expression was a favorable prognostic marker in HPV16‐negative but not HPV16‐positive patients. In conclusion, HPV‐positive tumors showed higher expression of immune markers. PD‐L1 expression constitutes an independent prognostic marker in SCCHN patients post‐adjuvant CRT. In conjunction with CD8 status, these data provide an important insight on the immune contexture of SCCHN and are directly relevant for future treatment stratification with PD‐1/PD‐L1 immune checkpoint inhibitors to complement CRT.     

Intratumoral forkhead box P3‐positive regulatory T cells predict poor survival in cyclooxygenase‐2–positive uveal melanoma

BACKGROUND:

Forkhead box P3 (FOXP3)‐positive regulatory T cells (Tregs) are key mediators of peripheral tolerance and suppress efficient antitumor responses. Prostaglandin E₂ (PGE₂) produced by inducible cyclooxygenase‐2 (COX‐2) can lead to Treg induction. COX‐2 expression has been linked to tumorigenesis and growth in various malignancies. The objective of the current study was to investigate whether Tregs infiltrate uveal melanomas (UMs) and whether their prevalence is linked to COX‐2 expression and the prediction of overall survival (OS).

METHODS:

One hundred patients who underwent enucleation after they were diagnosed with UM were included in the study. Immunohistochemical staining with monoclonal anti‐FOXP3, anti‐CD4, and anti‐COX‐2 antibodies was performed, and immunoreactivity was assessed. Correlations of COX‐2 expression with the presence of Tregs, established clinicopathologic parameters, and OS were evaluated in univariate and multivariate analyses.

RESULTS:

High expression of COX‐2 was predictive of shortened OS. FOXP3‐positive Tregs were detectable in 24% of UMs and were restricted to malignant tissue. The extent of COX‐2 expression was associated significantly with Treg prevalence (P = .004) and Treg intratumoral localization (P = .005). Intratumoral Tregs (but not the prevalence of Tregs) were independent marker for worse OS with a hazard ratio of 5.36 in patients with COX‐2–positive tumors.

CONCLUSIONS:

The current results demonstrated that high COX‐2 expression is associated with OS and Treg prevalence in UM. These findings are in line with the observations that COX‐2/PGE₂ induces Tregs and that Tregs may alter antitumor responses, resulting in a negative effect on the clinical disease course. Intratumoral Tregs are an independent prognostic marker for COX‐2–positive UM, and these results put COX‐2 inhibitors and Treg depletion into the spotlight of potential novel treatment modalities for patients with UM. Cancer 2010. © 2010 American Cancer Society.     

Plasma insulin‐like growth factor 1 is positively associated with low‐grade prostate cancer in the Health Professionals Follow‐up Study 1993–2004

The insulin‐like growth factor (IGF) axis plays a role in growth and progression of prostate cancer. High circulating IGF‐1 levels have been associated with an increased risk of prostate cancer. Results for IGF binding protein 3 (IGFBP‐3) are inconclusive. Some studies have indicated that the positive association with IGF‐1 is observed only for low‐grade prostate cancer (Gleason sum < 7). We previously reported in the Health Professionals Follow‐up Study (HPFS) a direct positive association between ELISA‐measured plasma IGF‐1 and IGFBP‐3 and risk of prostate cancer (462 cases diagnosed after providing a blood specimen (between 1993 and 1995), but before February 1998). With additional follow‐up through January 31st 2004, and 1,331 case–control pairs in total, we were now able to investigate low‐grade (Gleason sum < 7, n = 635) and high‐grade (Gleason sum ≥ 7, n = 515) prostate cancer separately. Matched odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. ORs of total prostate cancer comparing top to bottom quartiles were 1.41 (95% CI 1.12–1.78, p‐trend = 0.001) for IGF‐1 and 1.58 (95% CI 1.24–2.01, p‐trend = 0.003) for IGFBP‐3. IGF‐1 was more strongly associated with low‐grade (OR = 1.61 top versus bottom quartile, 95% CI 1.16–2.25, p‐trend = 0.01), than with high‐grade (OR = 1.29, 95% CI 0.89–1.88, p‐trend = 0.12) prostate cancer (p‐heterogeneity = 0.08). We hypothesize that these findings reflect that high‐grade prostate cancers are more autonomous, and, thus, less sensitive to the action of IGF‐1 than low‐grade cancers.     

Bevacizumab in combination with different platinum‐based doublets in the first‐line treatment for advanced nonsquamous non‐small‐cell lung cancer: A network meta‐analysis

Platinum‐based doublet chemotherapy with or without bevacizumab is the standard treatment for untreated advanced nonsquamous non‐small‐cell lung cancer (NS‐NSCLC). However, adding bevacizumab to chemotherapies other than paclitaxel–carboplatin is, though widely applied clinically, largely unjustified due to the lack of head‐to‐head data. We performed a Bayesian network meta‐analysis (NMA) to address this important issue. Data of 8,548 patients from 18 randomized controlled trials (RCTs) receiving six treatments, including taxane–platinum (Taxane–Pt), gemcitabine–platinum (Gem–Pt), pemetrexed–platinum (Pem–Pt), taxane–platinum + bevacizumab (Taxane–Pt + B), gemcitabine–platinum + bevacizumab (Gem–Pt + B) and pemetrexed–platinum + bevacizumab (Pem–Pt + B), were incorporated into the analyses. Direct and indirect evidence of overall survival (OS) and progression‐free survival (PFS) were synthesized at the hazard ratio (HR) scale and evidence of objective response rate (ORR) and serious adverse events (SAE) were synthesized at the odds ratio (OR) scale. Taxane–Pt + B showed significant advantages in OS (HR = 0.79, p < 0.001), PFS (HR = 0.54, p < 0.001) and ORR (OR = 2.7, p < 0.001) over Taxane–Pt with comparable tolerability (OR = 3.1, p = 0.08). Gem–Pt + B showed no OS benefit compared to any other treatment. No significant differences were detected between Pem–Pt + B and Pem–Pt in four outcomes. In terms of the benefit‐risk ratio, Pem–Pt and Taxane–Pt + B were ranked the first and second, respectively. In conclusion, in the first‐line treatment for advanced NS‐NSCLC, Taxane–Pt and Gem–Pt are the most and least preferable regimens to be used with bevacizumab, respectively. Adding bevacizumab to Pem–Pt remains unjustified because it fails to improve efficacy or tolerability. In terms of the benefit‐risk ratio, Pem–Pt and Taxane–Pt + B are the best and second‐best treatment for this population.     

Circulating 25‐hydroxyvitamin D,vitamin D‐binding protein and risk of prostate cancer

We recently reported a significant positive association between 25‐hydroxyvitamin D [25(OH)D], the accepted biomarker of vitamin D status, and prostate cancer risk. To further elucidate this association, we examined the influence of vitamin D‐binding protein (DBP), the primary transporter of vitamin D compounds in the circulation. Prediagnostic serum concentrations of DBP were assayed for 950 cases and 964 matched controls with existing 25(OH)D measurements within the Alpha‐Tocopherol, Beta‐Carotene Cancer Prevention Study of Finnish men. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), and statistical tests were two sided. Serum DBP modified the association between serum 25(OH)D and prostate cancer, with higher risk for elevated 25(OH)D levels observed primarily among men having DBP concentrations above the median (OR = 1.81, 95% CI: 1.18–2.79 for highest vs. lowest quintile, p‐trend = 0.001) compared to those with DBP below the median (OR = 1.22, 95% CI: 0.81–1.84, p‐trend 0.97; p‐interaction = 0.04). Serum DBP was not associated with prostate cancer risk overall (OR = 0.96, 95% CI: 0.70–1.33 for highest vs. lowest quintile); however, high serum DBP was associated with significantly decreased risk of prostate cancer in men with lower (<median) 25(OH)D concentrations (OR = 0.59, 95% CI: 0.38–0.90 for highest vs. lowest quintile, p‐trend = 0.003) and increased risk in men with higher 25(OH)D concentrations (OR = 1.47, 95% CI: 0.98–2.20, p‐trend 0.10, p‐interaction = 0.02). Our data suggest that the primary vitamin D carrier protein, DBP, modulates the impact of vitamin D status on prostate cancer.