Background Chronic inflammation is hypothesized to influence prostate cancer development, although a definitive link has not been established. Methods Prostate cancer cases (N=191) detected on a for-cause (clinically indicated) or end-of-study (protocol directed) biopsy, and frequency-matched controls (N=209), defined as negative for cancer on an end-of-study biopsy, were sampled from the placebo arm of the Prostate Cancer Prevention Trial. Inflammation prevalence and extent in benign areas of biopsy cores were visually assessed using digital images of H&E stained sections. Logistic regression was used to estimate associations. Results 86.2% of cases and 78.2% of controls had at least one biopsy core (of 3 assessed) with inflammation in benign areas, most of which was chronic. Men who had at least one biopsy core with inflammation had 1.78 (95% CI 1.04–3.06) times the odds of prostate cancer compared with men who had zero cores with inflammation. The association was stronger for high-grade disease (Gleason sum 7–10, N=94; odds ratio [OR]=2.24, 95% CI 1.06–4.71). These patterns were present when restricting to cases and controls in whom intraprostatic inflammation was the least likely to have influenced biopsy recommendation because their PSA was low (<2 ng/mL at biopsy). Conclusion Inflammation, most of which was chronic, was common in benign prostate tissue, and was positively associated with prostate cancer, especially high-grade. The association did not appear to be due to detection bias. Impact This study supports an etiologic link between inflammation and prostate carcinogenesis, and suggests an avenue for prevention by mitigating intraprostatic inflammation.

Prostate cancer continues to be a major health threat, especially among African American men. The Selenium and Vitamin E Cancer Prevention Trial (SELECT), which opened on July 25, 2001, was planned to study possible agents for the prevention of prostate cancer in a population of 32,400 men in the United States, including Puerto Rico, and Canada. SELECT is a phase III randomized, placebo-controlled trial of selenium (200 microg/day from L-selenomethionine) and/or vitamin E (400 IU/day of all rac alpha-tocopheryl acetate) supplementation for a minimum of 7 years (maximum of 12 years) in non-African American men at least 55 years of age and African American men at least 50 years of age. SELECT is a large, simple trial that conforms as closely as possible with community standards of care. This commentary discusses the design problems the SELECT investigators had to resolve in developing the trial, including the role of prostate cancer screening, the best forms and doses of the study agents, and estimation of the event (prostate cancer) rate of men on the placebo arm.

Statins are a class of low molecular weight drugs that inhibit the rate-limiting enzyme of the mevalonate pathway 3-hydroxy-3-methylglutaryl-CoA reductase. Statins have been approved and effectively used to control hypercholesterolemia in clinical setting. Recent study showed statin's antitumor activity and suggested a potential role for prevention of human cancers. In this study, we did cell viability, DNA fragmentation, and terminal deoxynucleotidyl transferase -mediated dUTP nick-end labeling assays to evaluate the action of statins on prostate cancer cells and used Western blotting and RhoA activation assay to investigate the underlying molecular mechanism of action. Our data showed that lovastatin and simvastatin effectively decreased cell viability in three prostate cancer cell lines (PC3, DU145, and LnCap) by inducing apoptosis and cell growth arrest at G 1 phase. Both lovastatin and simvastatin induced activation of caspase-8, caspase-3, and, to a lesser extent, caspase-9. Both statins suppressed expression of Rb, phosphorylated Rb, cyclin D1, cyclin D3, CDK4, and CDK6, but induced p21 and p27 expression in prostate cancer cells. Furthermore, lovastatin and simvastatin suppressed RhoA activation and c-JUN expression, but not cyclooxygenase-2 expression. Our data showed that the antitumor activity of statins is due to induction of apoptosis and cell growth arrest. The underlying molecular mechanism of statin's action is mediated through inactivation of RhoA, which in turn induces caspase enzymatic activity and/or G 1 cell cycle. Future studies should focus on examining statins and other apoptosisinducing drugs (e.g., cyclooxygenase-2 inhibitors or curcumin) together to assess their efficacy in prevention of prostate cancer. (Cancer Epidemiol Biomarkers Prev 2008;17(1):88 -94)

Altered microRNA (miRNA) expression has been found to promote carcinogenesis, but little is known about the role of miRNAs in esophageal cancer. In this study, we selected 10 miRNAs and analyzed their expression in 10 esophageal cancer cell lines and 158 tissue specimens using Northern blotting and in situ hybridization, respectively. We found that Let-7g, miR-21 and miR-195p were expressed in all 10 cell lines, miR-9 and miR-20a were not expressed in any of the cell lines, and miR-16-2, miR-30e, miR-34a, miR-126 and miR-200a were expressed in some of the cell lines but not others. In addition, transient transfection of miR-34a inhibited c-Met and cyclin D1 expression and esophageal cancer cell proliferation, whereas miR-16-2 suppressed RAR-b 2 expression and increased tumor cell proliferation. Furthermore, we found that miR-126 expression was associated with tumor cell dedifferentiation and lymph node metastasis, miR-16-2 was associated with lymph node metastasis, and miR-195p was associated with higher pathologic disease stages in patients with esophageal adenocarcinoma. Kaplan-Meier analysis showed that miR-16-2 expression and miR-30e expression were associated with shorter overall and disease-free survival in all esophageal cancer patients. In addition, miR-16-2, miR-30e and miR-200a expression were associated with shorter overall and disease-free survival in patients with esophageal adenocarcinoma; however, miR-16-2, miR-30e and miR-200a expression were not associated with overall or disease-free survival in squamous cell carcinoma patients. Our data indicate that further evaluation of miR-30e and miR-16-2 as prognostic biomarkers is warranted in patients with esophageal adenocarcinoma. In addition, the role of miR-34a in esophageal cancer also warrants further study.

Arachidonic acid (AA) is the major precursor of several classes of signal molecules and the alteration of its metabolism is involved in human carcinogenesis. For instance, 5-lipoxygenase (5-LOX) converts AA to hydroxyeicosatetraenoic acids or leukotrienes (LTs), which are able to enhance proliferation, increase survival and suppress the apoptosis of human cells. To determine the potential use of 5-LOX inhibitors in the prevention of esophageal cancer, we first analyzed the 5-LOX expression in esophageal tissue samples using immunohistochemistry and then examined the effect of the 5-LOX inhibitors AA861 and REV5901 on cell viability and apoptosis in esophageal cancer cell lines. 5-LOX expression was present in 79% (127/161) of esophageal cancer but in only 13% (4/32) of normal esophageal mucosa. 5-LOX was also expressed in all the eight esophageal cancer cell lines. Moreover, 5-LOX inhibitors caused a dose- and time-dependent reduction of cell viability, which was due to the induction of apoptosis and associated with LTB4 suppression. Our data also showed that both LTB4, a product of 5-LOX and LTB4 receptor antagonist U-75302 were able to prevent AA861 and REV5901 on induction of apoptosis. The present study demonstrated that 5-LOX protein expression is increased in esophageal cancer and that 5-LOX inhibitors can induce esophageal cancer cells to undergo apoptosis, suggesting that 5-LOX may be an effective target in the prevention of esophageal cancer.

15-Lipoxygenase-2 (15-LOX-2) synthesizes 15-S-hydroxyeicosatetraenoic acid (15-S-HETE), an endogenous ligand for the nuclear receptor, peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Several studies have described an inverse relationship between 15-LOX-2 and PPAR-gamma expression in normal versus tumor samples. To systematically determine if this is a ubiquitous phenomenon, we used a variety of epithelial and nonepithelial cells and some tissues to further evaluate the extent of this inverse relationship. The levels of mRNA or protein were measured by reverse transcriptase polymerase chain reaction or Western gray level intensity, whereas distribution was determined by in situ hybridization or immunofluorescence. 15-S-HETE was measured by liquid chromatography/tandem mass spectrometry. Normal epithelial cells/samples generally expressed high levels of 15-LOX-2 along with the enzyme product 15-S-HETE, but both levels were reduced in cancer cells/samples. In contrast, most cancer cells expressed high levels of PPAR-gamma mRNA and protein, which were absent from normal epithelial cells. Overall, the inverse relationship between these two genes was primarily restricted to epithelial samples. Forced expression of PPAR-gamma reduced 15-LOX-2 protein levels in normal cells, whereas forced expression of 15-LOX-2 in tumor cells suppressed PPAR-gamma protein levels. These results suggest that feedback mechanisms may contribute to the loss of 15-LOX-2 pathway components, which coincide with an increase in PPAR-gamma in many epithelial cancers.

The creation of single-nucleotide polymorphism (SNP) databases (such as NCBI dbSNP) has facilitated scientific research in many fields. SNP discovery and detection has improved to the extent that there are over 17 million human reference (rs) SNPs reported to date (Build 129 of dbSNP). SNP databases are unfortunately not always complete and/or accurate. In fact, half of the reported SNPs are still only candidate SNPs and are not validated in a population. We describe the identification of SNDs (Single Nucleotide Differences) in humans, that may contaminate the dbSNP database. These SNDs, reported as real SNPs in the database, do not exist as such, but are merely artifacts due to the presence of a paralogue (highly similar duplicated) sequence in the genome. Using sequencing we showed how SNDs could originate in two paralogous genes and evaluated samples from a population of 100 individuals for the presence/absence of SNPs. Moreover using bioinformatics, we predicted as many as 8.32% of the biallelic, coding SNPs in the dbSNP database to be SNDs. Our identification of SNDs in the database will allow researchers to not only select truly informative SNPs for association studies, but also aid in determining accurate SNP genotypes and haplotypes.

BACKGROUND Gastroesophageal reflux is a risk factor for esophageal adenocarcinoma and bile acid and its farnesoid X receptor (FXR) have been implicated in esophageal tumorigenesis. We investigated the role of FXR expression and activity in esophageal cancer initiation and growth. METHODS FXR expression in esophageal adenocarcinoma tissues was assessed by immunohistochemistry. Knockdown of FXR expression in esophageal cancer cells in vitro and in nude mice xenografts was suppressed by FXR shRNA and guggulsterone (a natural FXR inhibitor). Esophageal cancer cells were treated with bile acids to show their effects on growth-promoting genes. RESULTS FXR was expressed in 48 of 59 esophageal adenocarcinoma tissues (81.3%), and this overexpression was associated with higher tumor grade, greater tumor size, and lymph node metastasis, but was inversely associated with RAR-β2 expression. Knockdown of FXR expression suppressed tumor cell growth in vitro and in nude mouse xenografts. Guggulsterone reduced viability of esophageal cancer cells in a time- and dose-dependent manner, whereas this effect was diminished after knockdown of FXR expression. Guggulsterone induced apoptosis through activation of caspases-8, -9, and -3 in tumor cells. FXR mediated bile acid–induced alterations of gene expression, e.g., RAR-β2 and COX-2. CONCLUSION Inhibition of FXR by FXR shRNA or guggulsterone suppressed tumor cell viability and induced apoptosis in vitro and reduced tumor formation and growth in nude mouse xenografts. FXR mediated bile acid–induced alterations of cell growth-related genes in esophageal cancer cells.