Polymorphisms inside microRNAs and microRNA target sites predict clinical outcomes in prostate cancer patients receiving androgen-deprivation therapy

Single Nucleotide Polymorphisms Associated with Prostate Cancer Progression: A Systematic Review

BACKGROUND

New biomarkers of progression in patients with prostate cancer (PCa) are needed to improve their classification and clinical management. This systematic review investigated the relationship between single nucleotide polymorphisms (SNPs) and PCa progression.

METHODS

A keyword search was performed in Pubmed, EMBASE, Scopus, Web of Science, and Cochrane for publications between 2007 and 2022. We included articles with adjusted and significant associations, a median follow-up greater than or equal to 24 months, patients taken to radical prostatectomy (RP) as a first therapeutic option, and results presented based on biochemical recurrence (BCR).

RESULTS

In the 27 articles selected, 73 SNPs were identified in 39 genes, organized in seven functional groups. Of these, 50 and 23 SNPs were significantly associated with a higher and lower risk of PCa progression, respectively. Likewise, four haplotypes were found to have a significant association with PCa progression.

CONCLUSION

This article highlights the importance of SNPs as potential markers of PCa progression and their possible functional relationship with some genes relevant to its development and progression. However, most variants were identified only in cohorts from two countries; no additional studies reproduce these findings.

Analysis of genetic biomarkers, polymorphisms in ADME-related genes and their impact on pharmacotherapy for prostate cancer

Prostate cancer (PCa) is a non-cutaneous malignancy in males with wide variation in incidence rates across the globe. It is the second most reported cause of cancer death. Its etiology may have been linked to genetic polymorphisms, which are not only dominating cause of malignancy casualties but also exerts significant effects on pharmacotherapy outcomes. Although many therapeutic options are available, but suitable candidates identified by useful biomarkers can exhibit maximum therapeutic efficacy. The single-nucleotide polymorphisms (SNPs) reported in androgen receptor signaling genes influence the effectiveness of androgen receptor pathway inhibitors and androgen deprivation therapy. Furthermore, SNPs located in genes involved in transport, drug metabolism, and efflux pumps also influence the efficacy of pharmacotherapy. Hence, SNPs biomarkers provide the basis for individualized pharmacotherapy. The pharmacotherapeutic options for PCa include hormonal therapy, chemotherapy (Docetaxel, Mitoxantrone, Cabazitaxel, and Estramustine, etc.), and radiotherapy. Here, we overview the impact of SNPs reported in various genes on the pharmacotherapy for PCa and evaluate current genetic biomarkers with an emphasis on early diagnosis and individualized treatment strategy in PCa.

ATP8B1: A prognostic prostate cancer biomarker identified via genetic analysis

BACKGROUND

Controlling the asymmetric distribution of phospholipids across biological membranes plays a pivotal role in the life cycle of cells; one of the most important contributors that maintain this lipid asymmetry are phospholipid-transporting adenosine triphosphatases (ATPases). Although sufficient information regarding their association with cancer exists, there is limited evidence linking the genetic variants of phospholipid-transporting ATPase family genes to prostate cancer in humans.

METHODS

In this study, we investigated the association of 222 haplotype-tagging single-nucleotide polymorphisms (SNPs) in eight phospholipid-transporting ATPase genes with cancer-specific survival (CSS) and overall survival (OS) of 630 patients treated with androgen-deprivation therapy (ADT) for prostate cancer.

RESULTS

After multivariate Cox regression analysis and multiple testing correction, we found that ATP8B1 rs7239484 was remarkably associated with CSS and OS after ADT. A pooled analysis of multiple independent gene-expression datasets demonstrated that ATP8B1 was under-expressed in tumor tissues and that a higher ATP8B1 expression was associated with a better patient prognosis. Moreover, we established highly invasive sublines using two human prostate cancer cell lines to mimic cancer progression traits in vitro. The expression of ATP8B1 was consistently downregulated in both highly invasive sublines.

CONCLUSION

Our study indicates that rs7239484 is a prognostic factor for patients treated with ADT and that ATP8B1 can potentially attenuate prostate cancer progression.

The Cytidine N-Acetyltransferase NAT10 Participates in Peripheral Nerve Injury-Induced Neuropathic Pain by Stabilizing SYT9 Expression in Primary Sensory Neurons

RNA N4-acetylcytidine (ac4C) modification is increasingly recognized as an important layer of gene regulation; however, the involvement of ac4C in pain regulation has not been studied. Here, we report that N-acetyltransferase 10 protein (NAT10; the only known ac4C "writer") contributes to the induction and development of neuropathic pain in an ac4C-dependent manner. Peripheral nerve injury increases the levels of NAT10 expression and overall ac4C in injured dorsal root ganglia (DRGs). This upregulation is triggered by the activation of upstream transcription factor 1 (USF1), a transcription factor that binds to the Nat10 promoter. Knock-down or genetic deletion of NAT10 in the DRG abolishes the gain of ac4C sites in Syt9 mRNA and the augmentation of SYT9 protein, resulting in a marked antinociceptive effect in nerve-injured male mice. Conversely, mimicking NAT10 upregulation in the absence of injury evokes the elevation of Syt9 ac4C and SYT9 protein and induces the genesis of neuropathic-pain-like behaviors. These findings demonstrate that USF1-governed NAT10 regulates neuropathic pain by targeting Syt9 ac4C in peripheral nociceptive sensory neurons. Our findings establish NAT10 as a critical endogenous initiator of nociceptive behavior and a promising new target for treating neuropathic pain.SIGNIFICANCE STATEMENT The cytidine N4-acetylcytidine (ac4C), a new epigenetic RNA modification, is crucial for the translation and stability of mRNA, but its role for chronic pain remains unclear. Here, we demonstrate that N-acetyltransferase 10 (NAT10) acts as ac4C N-acetyltransferase and plays an important role in the development and maintenance of neuropathic pain. NAT10 was upregulated via the activation of the transcription factor upstream transcription factor 1 (USF1) in the injured dorsal root ganglion (DRG) after peripheral nerve injury. Since pharmacological or genetic deleting NAT10 in the DRG attenuated the nerve injury-induced nociceptive hypersensitivities partially through suppressing Syt9 mRNA ac4C and stabilizing SYT9 protein level, NAT10 may serve as an effective and novel therapeutic target for neuropathic pain.

A novel lysosome-related gene signature coupled with gleason score for prognosis prediction in prostate cancer

Background: Prostate cancer (PCa) is highly heterogeneous, which makes it difficult to precisely distinguish the clinical stages and histological grades of tumor lesions, thereby leading to large amounts of under- and over-treatment. Thus, we expect the development of novel prediction approaches for the prevention of inadequate therapies. The emerging evidence demonstrates the pivotal role of lysosome-related mechanisms in the prognosis of PCa. In this study, we aimed to identify a lysosome-related prognostic predictor in PCa for future therapies.

Methods: The PCa samples involved in this study were gathered from The Cancer Genome Atlas database (TCGA) (n = 552) and cBioPortal database (n = 82). During screening, we categorized PCa patients into two immune groups based on median ssGSEA scores. Then, the Gleason score and lysosome-related genes were included and screened out by using a univariate Cox regression analysis and the least absolute shrinkage and selection operation (LASSO) analysis. Following further analysis, the probability of progression free interval (PFI) was modeled by using unadjusted Kaplan–Meier estimation curves and a multivariable Cox regression analysis. A receiver operating characteristic (ROC) curve, nomogram and calibration curve were used to examine the predictive value of this model in discriminating progression events from non-events. The model was trained and repeatedly validated by creating a training set (n = 400), an internal validation set (n = 100) and an external validation (n = 82) from the cohort.

Results: Following grouping by ssGSEA score, the Gleason score and two LRGs—neutrophil cytosolic factor 1 (NCF1) and gamma-interferon-inducible lysosomal thiol reductase (IFI30)—were screened out to differentiate patients with or without progression (1-year AUC = 0.787; 3-year AUC = 0.798; 5-year AUC = 0.772; 10-year AUC = 0.832). Patients with a higher risk showed poorer outcomes (p < 0.0001) and a higher cumulative hazard (p < 0.0001). Besides this, our risk model combined LRGs with the Gleason score and presented a more accurate prediction of PCa prognosis than the Gleason score alone. In three validation sets, our model still achieved high prediction rates.

Conclusion: In conclusion, this novel lysosome-related gene signature, coupled with the Gleason score, works well in PCa for prognosis prediction.

Genome-Wide 3'-UTR Single Nucleotide Polymorphism Association Study Identifies Significant Prostate Cancer Risk-Associated Functional Loci at 8p21.2 in Chinese Population

MicroRNAs (miRNAs) are involved in the regulation of gene expression via incomplete base pairing to sequence motifs at the three prime untranslated regions (3'-UTRs) of mRNAs and play critical roles in the etiology of cancers. Single nucleotide polymorphisms (SNPs) in the 3'-UTR miRNA-binding regions may influence the miRNA affinity. However, this biological mechanism in prostate cancer (PCa) remains unclear. Here, a three-stage genome-wide association study of 3'-UTR SNPs (n=33 117) is performed in 5515 Chinese men. Three genome-wide significant variants are discovered at 8p21.2 (rs1567669, rs4872176, and rs4872177), which are all located in a linkage disequilibrium region of the NKX3-1 gene. Phenome-wide association analysis using the FinnGen data reveals a specific association of rs1567669 with PCa over 2,264 disease endpoints. Expression quantitative trait locus analyses based on both Chinese PCa cohort and the GTEx database show that risk alleles of these SNPs are significantly associated with low expression of NKX3-1. Based on the MirSNP database, dual-luciferase reporter assays show that risk alleles of these SNPs downregulate the expression of NKX3-1 via increased miRNA binding. These results indicate that the SNPs at the 3'-UTR of NKX3-1 significantly downregulate NKX3-1 expression by influencing the affinity of miRNA and increase the PCa risk.

The neonatal PROC gene rs1799809 polymorphism modifies the association between prenatal air pollutants exposure and PROC promoter methylation

Prenatal air pollution, protein C (PROC) gene abnormal methylation, and genetic mutation can cause a series of neonatal diseases, but the complex relationship between them remains unclear. Here, we recruited 552 mothers and their own babies during January 2010-January 2012 in Zhengzhou to explore such association. The air pollutant data was obtained from the Environmental Monitoring Stations. The rs1799809 genotype and the methylation levels at the promoter region of PROC in genomic DNA samples were detected respectively by TaqMan probe and quantitative methylation specific PCR using real-time PCR system. The results show that the levels of neonatal PROC methylation were negatively associated with concentrations of NO₂ during the entire pregnancy, particularly during the third trimester. Of particular significance, only in newborns carrying rs1799809 AA genotype, negatively significant associations between PROC methylation levels and exposure concentrations of air pollutants were observed. Further, we observed a significant interactive effect between neonatal rs1799809 genotype and SO₂ exposure during the entire pregnancy on neonatal PROC methylation levels. Prenatal exposure to ambient air pollutants specifically was associated with the neonatal PROC promoter methylation level of newborns carrying the rs1799809 AA genotype. Taken together, these findings suggest that neonatal PROC methylation levels are associated with prenatal exposure to ambient air pollutants, and this association can be modified by rs1799809 genotype.

Genetic Analysis Reveals the Prognostic Significance of the DNA Mismatch Repair Gene MSH2 in Advanced Prostate Cancer

Simple Summary

Androgen deprivation therapy is the most effective and widely used treatment for advanced prostate cancer, but its efficacy is highly variable among patients. Therefore, the identification of potent prognostic biomarkers is needed to determine patients at risk. We demonstrated that MSH2 rs1400633 was notably associated with patient survival during androgen deprivation therapy even after adjustment for clinical predictors and false discovery rate correction. Furthermore, our meta-analyses demonstrated that the MSH2 gene is highly expressed in prostate cancer and correlates positively with poor prognosis for this disease.

Abstract

DNA damage repair is frequently dysregulated in advanced prostate cancer and has been linked to cancer susceptibility and survival outcomes. The aim of this study is to assess the influence of genetic variants in DNA damage repair pathways on the prognosis of prostate cancer. Specifically, 167 single nucleotide polymorphisms (SNPs) in 18 DNA damage repair pathway genes were assessed for association with cancer-specific survival (CSS), overall survival (OS), and progression-free survival (PFS) in a cohort of 630 patients with advanced prostate cancer receiving androgen deprivation therapy. Univariate analysis identified four SNPs associated with CSS, four with OS, and two with PFS. However, only MSH2 rs1400633 C > G showed a significant association upon multivariate analysis and multiple testing adjustments (hazard ratio = 0.75, 95% confidence interval = 0.63–0.90, p = 0.002). Furthermore, rs1400633 risk allele C increased MSH2 expression in the prostate and other tissues, which correlated with more aggressive prostate cancer characteristics. A meta-analysis of 31 gene expression datasets revealed significantly higher MSH2 expression in prostate cancer than in normal tissues (p < 0.001), and this high expression was associated with a poor prognosis of prostate cancer (p = 0.002). In summary, we identified MSH2 rs1400633 as an independent prognostic biomarker for prostate cancer survival, and the association of MSH2 with cancer progression lends relevance to our findings.

MicroRNAs in Genetic Etiology of Human Diseases

Since their first discovery more than 20 years ago, miRNAs have been subject to deliberate research and analysis for revealing their physiological or pathological involvement. Regulatory roles of miRNAs in signal transduction, gene expression, and cellular processes in development, differentiation, proliferation, apoptosis, and homeostasis also imply their critical role in disease pathogenesis. Their roles in cancer, neurodegenerative diseases, and other systemic diseases have been studied broadly. In these regulatory pathways, their mutations and target sequence variations play critical roles to determine their functional repertoire. In this chapter, we summarize studies that investigated the role of mutations, polymorphisms, and other variations of miRNAs in respect to pathological processes.

IFI30 as a prognostic biomarker and correlation with immune infiltrates in glioma

Background

Increased evidence indicates that the tumour microenvironment (TME) plays an essential role in the development, treatment and prognosis of glioma. High expression of interferon-gamma-inducible protein 30 (IFI30) is associated with the malignant phenotype, but the effect of IFI30 on the tumour immune microenvironment and its potential role in the carcinogenesis of glioma remain unknown.

Methods

The RNA sequencing (RNA-seq) data of 33 types of human cancer were obtained from The Cancer Genome Atlas (TCGA) Genomic Data Commons (GDC). R software was used to perform analyses, such as the expression of IFI30 in pan-cancer, evaluation of IFI30 as a prognostic biomarker in glioma, the relationship between IFI30 expression and clinical characteristics, and immune checkpoint. TIMER was used to analyse the correlation of IFI30 expression level with immune cell infiltration, and also to conduct survival analysis for immune cells and IFI30 in low grade glioma (LGG). DAVID was used for Gene Ontology (GO) functional annotations and Kyoto Encyclopedia of Genes and Genomes (KEGG) for pathway analysis of the genes similar to IFI30 in glioma. The differentially expressed genes (DEGs) between the high- and low-IFI30 expression groups were determined by DESeq2. Gene set enrichment analysis (GSEA) was then conducted to identify IFI30-related functional significance based on the hallmark gene set.

Results

Dysregulated expression of IFI30 was associated with human cancers. High IFI30 expression was associated with poor overall survival (OS), disease-specific survival (DSS) and progression-free interval (PFI). Univariate and multivariate analyses identified IFI30 as an independent predictor for glioma. Meanwhile, IFI30 overexpression significantly correlated with high-grade tumours, poor OS, and immune infiltration. In addition, IFI30-associated genes significantly enriched the hallmark tumour progression-related clusters and cancer pathways.

Conclusions

IFI30 is a prognostic biomarker correlated with immune infiltrates and acts as an oncogene in glioma.

NRG1 Genetic Variant Influences the Efficacy of Androgen-Deprivation Therapy in Men with Prostate Cancer

Neuregulins (NRGs) activate receptor tyrosine kinases of the ErbB family, and play essential roles in the proliferation, survival, and differentiation of normal and malignant tissue cells. We hypothesized that genetic variants of NRG signalling pathway genes may influence treatment outcomes in prostate cancer. To test this hypothesis, we performed a comprehensive analysis to evaluate the associations of 459 single-nucleotide polymorphisms in 19 NRG pathway genes with cancer-specific survival (CSS), overall survival (OS), and progression-free survival (PFS) in 630 patients with prostate cancer receiving androgen-deprivation therapy (ADT). After multivariate Cox regression and multiple testing correction, we found that NRG1 rs144160282 C > T is significantly associated with worsening CSS, OS, and PFS during ADT. Further analysis showed that low expression of NRG1 is closely related to prostate cancer, as indicated by a high Gleason score, an advanced stage, and a shorter PFS rate. Meta-analysis of 16 gene expression datasets of 1,081 prostate cancer samples and 294 adjacent normal samples indicate lower NRG1 expression in the former compared with the latter (p < 0.001). These results suggest that NRG1 rs144160282 might be a prognostic predictor of the efficacy of ADT. Further studies are required to confirm the significance of NRG1 as a biomarker and therapeutic target for prostate cancer.

PTBP1 Genetic Variants Affect the Clinical Response to Androgen-deprivation Therapy in Patients With Prostate Cancer

BACKGROUND/AIM

Heterogeneous nuclear ribonucleoproteins (hnRNPs) contribute to multiple cellular functions including RNA splicing, stabilization, transcriptional and translational regulation, and signal transduction. However, the prognostic importance of genetic variants of hnRNP genes in clinical outcomes of prostate cancer remains to be elucidated.

PATIENTS AND METHODS

We studied the association of 78 germline single-nucleotide polymorphisms (SNPs) in 23 hnRNP genes with the overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS) in 630 patients with prostate cancer receiving androgen-deprivation therapy (ADT).

RESULTS

PTBP1 rs10420407 was the most significant SNP (false discovery rate q=0.003) and carriers of the A allele exhibited poor OS, CSS, and PFS. Multivariate Cox analysis confirmed PTBP1 rs10420407 A allele was an independent negative prognostic factor for OS and PFS. Expression quantitative trait loci analysis showed that the rs10420407 A allele had a trend towards increased PTBP1 mRNA expression, and higher expression was correlated with prostate cancer aggressiveness and poor patient prognosis. Meta-analysis of 16 independent studies further indicated a tumorigenic effect of PTBP1, with a higher expression in prostate cancers than in adjacent normal tissues (p<0.001).

CONCLUSION

Our data suggest that PTBP1 rs10420407 may influence patient response to ADT, and PTBP1 may be involved in the pathogenesis of prostate cancer progression.

Genetic Polymorphisms and Pharmacotherapy for Prostate Cancer

The therapeutic landscape of pharmacotherapy for prostate cancer has dramatically evolved, and multiple therapeutic options have become available for prostate cancer patients. Therefore, useful biomarkers to identify suitable candidates for treatment are required to maximize the efficacy of pharmacotherapy. Genetic polymorphisms such as single-nucleotide polymorphisms (SNPs) and tandem repeats have been shown to influence the therapeutic effects of pharmacotherapy for prostate cancer patients. For example, genetic polymorphisms in the genes involved in androgen receptor signaling are reported to be associated with the therapeutic outcome of androgen-deprivation therapy as well as androgen receptor-pathway inhibitors. In addition, SNPs in genes involved in drug metabolism and efflux pumps are associated with therapeutic effects of taxane chemotherapy. Thus, genetic polymorphisms such as SNPs are promising biomarkers to realize personalized medicine. Here, we overview the current findings on the influence of genetic polymorphisms on the outcome of pharmacotherapy for prostate cancer and discuss current issues as well as future visions in this field.

IFI30 expression predicts patient prognosis in breast cancer and dictates breast cancer cells proliferation via regulating autophagy

Introduction: Incidence and mortality rates of breast cancer are increasing in women worldwide. Immunotherapy is a relatively popular treatment modality for all malignant tumors including breast cancer in recent years. Interferon γ-inducible protein 30 (IFI30) could catalyze the reduction of disulfide bonds and enhance major histocompatibility complex (MHC) class II-restricted antigen processing. Recent studies showed that IFI30 played an important role in the immune response of malignant tumors. Methods: The Cancer Genome Atlas (TCGA) database and clinical proteomic tumor Analysis consortium (CPTAC) database were applied to predict the role of IFI30 in breast cancer and the relationship between IFI30 and prognosis of breast cancer patients. Then we detected the expression of IFI30 in clinical samples of breast cancer patients, and analyzed the relationship between IFI30 and the prognosis of breast cancer patients. We used lentivirus infection method to construct a stable IFI30 knockdown cell line, and detected the effect of IFI30 in breast cancer cells. Nude mice tumor bearing experiment was performed to investigate the effect of IFI30 on breast cancer cells in vivo. Western blot was used to verify the regulation of autophagy related protein LC3 and p62 by IFI30. Results: We found that IFI30 was highly expressed in breast cancer tissues and was associated with poor outcome of patients. The knockdown of IFI30 could inhibit the proliferation, migration and invasion of breast cancer cells and significantly inhibit tumor growth in vivo. Increased accumulation of LC3-II and p62 suggested impaired autophagy in IFI30 knockdown cells. Discussion: As a result, we suggested that IFI30 might play a key role in the initiation and progression of human breast cancer and might be a new therapeutic target in breast cancer.

A Phase I/II Trial of MEC (Mitoxantrone, Etoposide, Cytarabine) in Combination with Ixazomib for Relapsed Refractory Acute Myeloid Leukemia

PURPOSE

The prognosis of patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) remains poor, and novel therapies are needed. The proteasome pathway represents a potential therapeutic target. A phase I trial of the second-generation proteasome inhibitor ixazomib in combination with MEC (mitoxantrone, etoposide, and cytarabine) was conducted in patients with R/R AML.

PATIENTS AND METHODS

Dose escalation of ixazomib was performed using a standard 3 × 3 design. Gene-expression profiling was performed on pretreatment and posttreatment bone marrow or blood samples.

RESULTS

The maximum tolerated dose of ixazomib in combination with MEC was 1.0 mg. The dose limiting toxicity was thrombocytopenia. Despite a poor risk population, the response rate [complete remission (CR)/CR with incomplete count recovery (CRi)] was encouraging at 53%. Gene-expression analysis identified two genes, IFI30 (γ-interferon inducible lysosomal thiol reductase) and RORα (retinoic orphan receptor A), which were significantly differentially expressed between responding and resistant patients and could classify CR.

CONCLUSIONS

These results are encouraging, but a randomized trial is needed to address whether the addition of ixazomib to MEC improves outcome. Gene-expression profiling also helped us identify predictors of response and potentially novel therapeutic targets.

Genetic variants in the circadian rhythm pathway as indicators of prostate cancer progression

Background

To determine the association between circadian pathway genetic variants and the risk of prostate cancer progression.

Methods

We systematically evaluated 79 germline variants in nine circadian pathway genes in a cohort of 458 patients with localized prostate cancer as the discovery phase. We then replicated the significant findings in another cohort of 324 men with more advanced disease. The association of each variant with prostate cancer progression was evaluated by a log-rank test and Cox regression.

Results

A single nucleotide polymorphism of the neuronal PAS domain protein 2 (NPAS2) gene (rs6542993 A>T) was found to be associated with a significantly higher risk of disease progression in both localized (P = 0.001) and advanced (P = 0.039) prostate cancer cases. In silico analysis revealed decreased expression levels of NPAS2 in carriers of the T allele of rs6542993 compared with those carrying the A allele. Consistently, downregulation of NPAS2 expression was associated with more aggressive prostate cancer and poor progression-free survival (log-rank P = 0.002).

Conclusions

The NPAS2 rs6542993 polymorphism may be a promising biomarker, and may shed light on the pathways that govern prostate cancer progression.

Functional microRNA binding site variants

Germline single nucleotide polymorphisms are one of the most common genetic variations. Polymorphisms that cause nonsynonymous mutations in gene coding regions are known to cause serious deleterious downstream effects. However, even polymorphisms in noncoding regions can have profound functional consequences by disrupting essential regulatory sites. Specifically, polymorphisms that alter microRNA binding sites can disrupt the regulation of hallmark biological pathways implicated in tumorigenesis and tumor progression. Many of these microRNA-associated polymorphisms (miR-SNPs) have recently been shown to be important biomarkers of cancer risk, prognosis, and treatment outcomes. This review will summarize the functional impact of key miR-SNPs and define a subset of miR-SNPs that may be clinically useful prognostic or predictive biomarkers.

Post-GWAS in prostate cancer: from genetic association to biological contribution

Genome-wide association studies (GWAS) have been successful in deciphering the genetic component of predisposition to many human complex diseases including prostate cancer. Germline variants identified by GWAS progressively unravelled the substantial knowledge gap concerning prostate cancer heritability. With the beginning of the post-GWAS era, more and more studies reveal that, in addition to their value as risk markers, germline variants can exert active roles in prostate oncogenesis. Consequently, current research efforts focus on exploring the biological mechanisms underlying specific susceptibility loci known as causal variants by applying novel and precise analytical methods to available GWAS data. Results obtained from these post-GWAS analyses have highlighted the potential of exploiting prostate cancer risk-associated germline variants to identify new gene networks and signalling pathways involved in prostate tumorigenesis. In this Review, we describe the molecular basis of several important prostate cancer-causal variants with an emphasis on using post-GWAS analysis to gain insight into cancer aetiology. In addition to discussing the current status of post-GWAS studies, we also summarize the main molecular mechanisms of potential causal variants at prostate cancer risk loci and explore the major challenges in moving from association to functional studies and their implication in clinical translation.

Identification of miR-200c and miR141-Mediated lncRNA-mRNA Crosstalks in Muscle-Invasive Bladder Cancer Subtypes

Basal and luminal subtypes of muscle-invasive bladder cancer (MIBC) have distinct molecular profiles and heterogeneous clinical behaviors. The interactions between mRNAs and lncRNAs, which might be regulated by miRNAs, have crucial roles in many cancers. However, the miRNA-dependent crosstalk between lncRNA and mRNA in specific MIBC subtypes still remains unclear. In this study, we first classified MIBC into two conservative subtypes using miRNA, mRNA and lncRNA expression data derived from The Cancer Genome Atlas. Then we investigated subtype-related biological pathways and evaluated the subtype classification performance using Decision Trees, Random Forest and eXtreme Gradient Boosting (XGBoost). At last, we explored potential miRNA-mediated lncRNA-mRNA crosstalks based on co-expression analysis. Our results show that: (1) the luminal subtype is primarily characterized by upregulation of metabolism-related pathways while the basal subtype is predominantly characterized by upregulation of epithelial-mesenchymal transition, metastasis, and immune system process-related pathways; (2) the XGBoost prediction model is consistently robust for classification of the molecular subtypes of MIBC across four datasets (The area under the ROC curve > 0.9); (3) the expression levels of the molecules in the miR-200c and miR141-mediated lncRNA-mRNA crosstalks differ considerably between the two subtypes and have close relationships with the prognosis of MIBC. The miR-200c and miR-141-dependent mRNA-lncRNA crosstalks might be of great significance in tumorigenesis and tumor progression and may serve as the novel prognostic predictors and classification markers of MIBC subtypes.

A common regulatory variant in SLC35B4 influences the recurrence and survival of prostate cancer

Single nucleotide polymorphisms (SNPs) within the regulatory elements of a gene can alter gene expression, making these SNPs of prime importance for candidate gene association studies. We aimed to determine whether such regulatory variants are associated with clinical outcomes in three cohorts of patients with prostate cancer. We used RegulomeDB to identify potential regulatory variants based on in silico predictions and reviewed genome‐wide experimental findings. Overall, 131 putative regulatory SNPs with the highest confidence score on predicted functionality were investigated in two independent localized prostate cancer cohorts totalling 458 patients who underwent radical prostatectomy. The statistically significant SNPs identified in these two cohorts were then tested in an additional cohort of 504 patients with advanced prostate cancer. We identified one regulatory SNPs, rs1646724, that are consistently associated with increased risk of recurrence in localized disease (P = .003) and mortality in patients with advanced prostate cancer (P = .032) after adjusting for known clinicopathological factors. Further investigation revealed that rs1646724 may affect expression of SLC35B4, which encodes a glycosyltransferase, and that down‐regulation of SLC35B4 by transfecting short hairpin RNA in DU145 human prostate cancer cell suppressed proliferation, migration and invasion. Furthermore, we found increased SLC35B4 expression correlated with more aggressive forms of prostate cancer and poor patient prognosis. Our study provides robust evidence that regulatory genetic variants can affect clinical outcomes.

Vitamin D receptor-binding site variants affect prostate cancer progression

Vitamin D is an important modulator of cellular proliferation through the vitamin D receptor (VDR) that binds to DNA in the regulatory sequences of target genes. We hypothesized that single nucleotide polymorphisms (SNPs) in VDR-binding sites might affect target gene expression and influence the progression of prostate cancer. Using a genome-wide prediction database, 62 SNPs in VDR-binding sites were selected for genotyping in 515 prostate cancer patients and the findings were replicated in an independent cohort of 411 patients. Prognostic significance on prostate cancer progression was assessed by Kaplan-Meier analysis and the Cox regression model. According to multivariate analyses adjusted for known predictors, HFE rs9393682 was found to be associated with disease progression for localized prostate cancer, and TUSC3 rs1378033 was associated with progression for advanced prostate cancer in both cohorts. Vitamin D treatment inhibited HFE mRNA expression, and down-regulation of HFE by transfecting small interfering RNA suppressed PC-3 human prostate cancer cell proliferation and wound healing ability. In contrast, vitamin D treatment induced TUSC3 expression, and silencing TUSC3 promoted prostate cancer cell growth and migration. Further analysis of an independent microarray dataset confirmed that low TUSC3 expression correlated with poor patient prognosis. Our results warrant further studies using larger cohorts. This study identifies common variants in VDR-binding sites as prognostic markers of prostate cancer progression and HFE and TUSC3 as plausible susceptibility genes.

Identification of a New Single-nucleotide Polymorphism within the Apolipoprotein A5 Gene, Which is Associated with Metabolic Syndrome

Background:

Metabolic syndrome (MetS) is a common disorder which is a constellation of clinical features including abdominal obesity, increased level of serum triglycerides (TGs) and decrease of serum high-density lipoprotein-cholesterol (HDL-C), elevated blood pressure, and glucose intolerance. The apolipoprotein A5 (APOA5) is involved in lipid metabolism, influencing the level of plasma TG and HDL-C. In the present study, we aimed to investigate the associations between four INDEL variants of APOA5 gene and the MetS risk.

Materials and Methods:

In this case–control study, we genotyped 116 Iranian children and adolescents with/without MetS by using Sanger sequencing method for these INDELs. Then, we explored the association of INDELs with MetS risk and their clinical components by logistic regression and one-way analysis of variance analyses.

Results:

We identified a novel insertion polymorphism, c. *282–283 insAG/c. *282–283 insG variant, which appears among case and control groups. rs72525532 showed a significant difference for TG levels between various genotype groups. In addition, there were significant associations between newly identified single-nucleotide polymorphism (SNP) and rs72525532 with MetS risk.

Conclusions:

These results show that rs72525532 and the newly identified SNP may influence the susceptibility of the individuals to MetS.

Inherited Variants in Wnt Pathway Genes Influence Outcomes of Prostate Cancer Patients Receiving Androgen Deprivation Therapy

Aberrant Wnt signaling has been associated with many types of cancer. However, the association of inherited Wnt pathway variants with clinical outcomes in prostate cancer patients receiving androgen deprivation therapy (ADT) has not been determined. Here, we comprehensively studied the contribution of common single nucleotide polymorphisms (SNPs) in Wnt pathway genes to the clinical outcomes of 465 advanced prostate cancer patients treated with ADT. Two SNPs, adenomatous polyposis coli (APC) rs2707765 and rs497844, were significantly (p ≤ 0.009 and q ≤ 0.043) associated with both prostate cancer progression and all-cause mortality, even after multivariate analyses and multiple testing correction. Patients with a greater number of favorable alleles had a longer time to disease progression and better overall survival during ADT (p for trend ≤ 0.003). Additional, cDNA array and in silico analyses of prostate cancer tissue suggested that rs2707765 affects APC expression, which in turn is correlated with tumor aggressiveness and patient prognosis. This study identifies the influence of inherited variants in the Wnt pathway on the efficacy of ADT and highlights a preclinical rationale for using APC as a prognostic marker in advanced prostate cancer.

MiRNAs and miRNA Polymorphisms Modify Drug Response

Differences in expression of drug response-related genes contribute to inter-individual variation in drugs’ biological effects. MicroRNAs (miRNAs) are small noncoding RNAs emerging as new players in epigenetic regulation of gene expression at post-transcriptional level. MiRNAs regulate the expression of genes involved in drug metabolism, drug transportation, drug targets and downstream signal molecules directly or indirectly. MiRNA polymorphisms, the genetic variations affecting miRNA expression and/or miRNA-mRNA interaction, provide a new insight into the understanding of inter-individual difference in drug response. Here, we provide an overview of the recent progress in miRNAs mediated regulation of biotransformation enzymes, drug transporters, and nuclear receptors. We also describe the implications of miRNA polymorphisms in cancer chemotherapy response.

miRNA-dependent target regulation: functional characterization of single-nucleotide polymorphisms identified in genome-wide association studies of Alzheimer's disease

Background

A growing body of evidence suggests that microRNAs (miRNAs) are involved in Alzheimer’s disease (AD) and that some disease-associated genetic variants are located within miRNA binding sites. In the present study, we sought to characterize functional polymorphisms in miRNA target sites within the loci defined in earlier genome-wide association studies (GWAS). The main objectives of this study were to (1) facilitate the identification of the gene or genes responsible for the GWAS signal within a locus of interest and (2) determine how functional polymorphisms might be involved in the AD process (e.g., by affecting miRNA-mediated variations in gene expression).

Methods

Stringent in silico analyses were developed to select potential polymorphisms susceptible to impairment of miRNA-mediated repression, and subsequent functional assays were performed in HeLa and HEK293 cells.

Results

Two polymorphisms were identified and further analyzed in vitro. The AD-associated rs7143400-T allele (located in 3′ untranslated region [3′-UTR] of FERMT2) cotransfected with miR-4504 resulted in lower protein levels relative to the rs7143400-G allele cotransfected with the same miRNA. The AD-associated rs9909-C allele in the 3′-UTR of NUP160 abolished the miR-1185-1-3p-regulated expression observed for the rs9909-G allele.

Conclusions

When considered in conjunction with the findings of previous association studies, our results suggest that decreased expression of FERMT2 might be a risk factor in the etiopathology of AD, whereas increased expression of NUP160 might protect against the disease. Our data therefore provide new insights into AD by highlighting two new proteins putatively involved in the disease process.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-016-0186-x) contains supplementary material, which is available to authorized users.

Genetic variants in ultraconserved regions associate with prostate cancer recurrence and survival

Ultraconserved regions (UCRs) are DNA segments of longer than 200 bp in length that are completely conserved between human, rat, and mouse genomes. Recent studies have shown that UCRs are frequently located at fragile sites involved in cancers, and their levels of transcription can be altered during human tumorigenesis. We systematically evaluated 14 common single-nucleotide polymorphisms (SNPs) within UCRs in three cohorts of prostate cancer patients, to test the hypothesis that these UCR SNPs might influence clinical outcomes. Examination using multivariate analysis adjusted for known clinicopathologic factors found association between rs8004379 and recurrence in localized disease [hazard ratio (HR) 0.61, 95% confidence interval (CI) 0.41–0.91, P = 0.015], which was confirmed in the replication set (HR 0.70, 95% CI 0.51–0.96, P = 0.027). Remarkably, a consistent association of rs8004379 with a decreased risk for prostate cancer-specific mortality was also observed in the advanced prostate cancer patient group (HR 0.48, 95% CI 0.32–0.70, P < 0.001). Additional in silico analysis suggests that rs8004379 tends to affect NPAS3 expression, which in turn was found to be correlated with patient prognosis. In conclusion, our findings suggest that SNPs within UCRs may be valuable prognostic biomarkers for assessing prostate cancer treatment response and survival.

Genetic variants of the autophagy pathway as prognostic indicators for prostate cancer

Autophagy is a complex process of autodigestion in conditions of cellular stress, and it might play an important role in the pathophysiology during carcinogenesis. We hypothesize that genetic variants of the autophagy pathway may influence clinical outcomes in prostate cancer patients. We genotyped 40 tagging single-nucleotide polymorphisms (SNPs) from 7 core autophagy pathway genes in 458 localized prostate cancer patients. Multivariate Cox regression was performed to evaluate the independent association of each SNP with disease progression. Positive findings were then replicated in an independent cohort of 504 advanced prostate cancer patients. After adjusting for known clinicopathologic factors, the association between ATG16L1 rs78835907 and recurrence in localized disease [hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.54–0.90, P = 0.006] was replicated in more advanced disease (HR 0.78, 95% CI 0.64–0.95, P = 0.014). Additional integrated in silico analysis suggests that rs78835907 tends to affect ATG16L1 expression, which in turn is correlated with tumor aggressiveness and patient prognosis. In conclusion, genetic variants of the autophagy pathway contribute to the variable outcomes in prostate cancer, and discovery of these novel biomarkers might help stratify patients according to their risk of disease progression.

A Large-Scale Analysis of Genetic Variants within Putative miRNA Binding Sites in Prostate Cancer

Prostate cancer is the second most common malignancy among men worldwide. Genome-wide association studies have identified 100 risk variants for prostate cancer, which can explain approximately 33% of the familial risk of the disease. We hypothesized that a comprehensive analysis of genetic variations found within the 3' untranslated region of genes predicted to affect miRNA binding (miRSNP) can identify additional prostate cancer risk variants. We investigated the association between 2,169 miRSNPs and prostate cancer risk in a large-scale analysis of 22,301 cases and 22,320 controls of European ancestry from 23 participating studies. Twenty-two miRSNPs were associated (P<2.3×10(-5)) with risk of prostate cancer, 10 of which were within 7 genes previously not mapped by GWAS studies. Further, using miRNA mimics and reporter gene assays, we showed that miR-3162-5p has specific affinity for the KLK3 rs1058205 miRSNP T-allele, whereas miR-370 has greater affinity for the VAMP8 rs1010 miRSNP A-allele, validating their functional role.

SIGNIFICANCE

Findings from this large association study suggest that a focus on miRSNPs, including functional evaluation, can identify candidate risk loci below currently accepted statistical levels of genome-wide significance. Studies of miRNAs and their interactions with SNPs could provide further insights into the mechanisms of prostate cancer risk.

Genetic analysis and preliminary function study of miR-423 in breast cancer

Common genetic variants (single nucleotide polymorphisms SNPs) in microRNA (miRNA) genes may alter their maturation or expression and play a role in the formation of human cancer. Recently, the association between the SNP rs6505162 in pre-miR-423 and cancer risk has been frequently evaluated in diverse populations and in a range of cancers. In this study, we determined the genotypes of SNP rs6505162 in 5 matched cell lines (breast cancer cell lines and their corresponding peripheral blood cell lines) and 114 matched clinical specimens (clinical breast carcinoma specimens and their corresponding normal tissues), compared the processing efficiency of pri-miRNA to mature forms between pre-miR-423-12C (wild-type) and pre-miR-423-12A (mutant-type) expression vectors, and evaluated the function of miR-423 on cell proliferation. Our data showed that two out of five breast cancer cell lines and 8.77 % (10/114) of tumors underwent somatic mutations of the rs6505162 SNP, and somatic mutation state was significantly correlated with the expression of clinicopathologic variables, proliferating cell nuclear antigen (PCNA) and mutant p53. The pre-miR-423-12C SNP blocked the endogenous processing of pri-miR-423 to its two mature miRNAs. Interestingly, selected pre-miR-423-12C stable cell population had lower proliferation ability than pre-miR-423-12A stable cell population. Moreover, miR-423 promoted cell proliferation in breast cancer cell lines through its miR-423-3p strand, not miR-423-5p. Taken together, these results suggest that the SNP rs6505162 in pre-miR-423 affects the mature miR expression, and miR-423 plays a potentially oncogenic role in breast tumorigenesis.

Genetic variation: effect on prostate cancer

The crucial role of androgens in the development of prostate cancer is well established. The aim of this review is to examine the role of constitutional (germline) and tumor-specific (somatic) polymorphisms within important regulatory genes of prostate cancer. These include genes encoding enzymes of the androgen biosynthetic pathway, the androgen receptor gene, genes that encode proteins of the signal transduction pathways that may have a role in disease progression and survival, and genes involved in prostate cancer angiogenesis. Characterization of deregulated pathways critical to cancer cell growth have lead to the development of new treatments, including the CYP17 inhibitor abiraterone and clinical trials using novel drugs that are ongoing or recently completed [1]. The pharmacogenetics of the drugs used to treat prostate cancer will also be addressed. This review will define how germline polymorphisms are known affect a multitude of pathways, and therefore phenotypes, in prostate cancer etiology, progression, and treatment.

Regulation by miR181 family of the dependence receptor CDON tumor suppressive activity in neuroblastoma

BACKGROUND

The Sonic Hedgehog (SHH) signaling pathway plays an important role in neural crest cell fate during embryonic development and has been implicated in the progression of multiple cancers that include neuroblastoma, a neural crest cell-derived disease. While most of the SHH signaling is mediated by the well-described canonical pathway leading to the activation of Smoothened and Gli, it has recently been shown that cell-adhesion molecule-related/downregulated by oncogenes (CDON) serves as a receptor for SHH and contributes to SHH-induced signaling. CDON has also been recently described as a dependence receptor, triggering apoptosis in the absence of SHH. This CDON proapoptotic activity has been suggested to constrain tumor progression.

METHODS

CDON expression was analyzed by quantitative-reverse transcription-polymerase chain reaction in a panel of 226 neuroblastoma patients and associated with stages, overall survival, and expression of miR181 family members using Kaplan Meier and Pearson correlation methods. Cell death assays were performed in neuroblastoma cell lines and tumor growth was investigated in the chick chorioallantoic model. All statistical tests were two-sided.

RESULTS

CDON expression was inversely associated with neuroblastoma aggressiveness (P < .001). Moreover, re-expression of CDON in neuroblastoma cell lines was associated with apoptosis in vitro and tumor growth inhibition in vivo. We show that CDON expression is regulated by the miR181 miRNA family, whose expression is directly associated with neuroblastoma aggressiveness (survival: high miR181-b 73.2% vs low miR181-b 54.6%; P = .03).

CONCLUSIONS

Together, these data support the view that CDON acts as a tumor suppressor in neuroblastomas, and that CDON is tightly regulated by miRNAs.

Genetic variants in microRNAs and microRNA target sites predict biochemical recurrence after radical prostatectomy in localized prostate cancer

Recent evidence indicates that microRNAs might participate in prostate cancer initiation, progression and treatment response. Germline variations in microRNAs might alter target gene expression and modify the efficacy of prostate cancer therapy. To determine whether genetic variants in microRNAs and microRNA target sites are associated with the risk of biochemical recurrence (BCR) after radical prostatectomy (RP). We retrospectively studied two independent cohorts composed of 320 Asian and 526 Caucasian men with pathologically organ-confined prostate cancer who had a median follow-up of 54.7 and 88.8 months after RP, respectively. Patients were systematically genotyped for 64 single-nucleotide polymorphisms (SNPs) in microRNAs and microRNA target sites, and their prognostic significance on BCR was assessed by Kaplan-Meier analysis and Cox regression model. After adjusting for known clinicopathologic risk factors, two SNPs (MIR605 rs2043556 and CDON rs3737336) remained associated with BCR. The numbers of risk alleles showed a cumulative effect on BCR [perallele hazard ratio (HR) 1.60, 95% confidence interval (CI) 1.16-2.21, p for trend = 0.005] in Asian cohort, and the risk was replicated in Caucasian cohort (HR 1.55, 95% CI 1.15-2.08, p for trend = 0.004) and in combined analysis (HR 1.57, 95% CI 1.26-1.96, p for trend <0.001). Results warrant replication in larger cohorts. This is the first study demonstrating that SNPs in microRNAs and microRNA target sites can be predictive biomarkers for BCR after RP.

The role of single nucleotide polymorphisms in predicting prostate cancer risk and therapeutic decision making

Prostate cancer (PCa) is a major health care problem because of its high prevalence, health-related costs, and mortality. Epidemiological studies have suggested an important role of genetics in PCa development. Because of this, an increasing number of single nucleotide polymorphisms (SNPs) had been suggested to be implicated in the development and progression of PCa. While individual SNPs are only moderately associated with PCa risk, in combination, they have a stronger, dose-dependent association, currently explaining 30% of PCa familial risk. This review aims to give a brief overview of studies in which the possible role of genetic variants was investigated in clinical settings. We will highlight the major research questions in the translation of SNP identification into clinical practice.

Genetic variations in TP53 binding sites are predictors of clinical outcomes in prostate cancer patients

Since the tumor protein p53 (TP53), a transcription factor, plays a crucial role in prostate cancer development and progression, we hypothesized that sequence variants in TP53 binding sites might affect clinical outcomes in patients with prostate cancer. We systematically evaluated 41 single nucleotide polymorphisms (SNPs) within genome-wide predicted TP53 binding sites in a cohort of 1,024 prostate cancer patients. The associations of these SNPs with prostate cancer characteristics and clinical outcomes after radical prostatectomy for localized disease and after androgen-deprivation therapy (ADT) for advanced disease were assessed by Kaplan-Meier analysis and Cox regression model. ARAP2 rs1444377 and TRPS1 rs722740 were associated with advanced stage prostate cancer. FRK rs171866 remained as a significant predictor for disease progression; DAB2 rs268091 and EXOC4 rs1149558 remained as significant predictors for prostate cancer-specific mortality (PCSM); and EXOC4 rs1149558 remained as a significant predictor for all-cause mortality after ADT in multivariate models that included clinicopathologic predictors. In addition, the numbers of protective genotypes at DAB2 rs268091 and EXOC4 rs1149558 showed a cumulative effect on PCSM (P for trend = 0.002). Our results suggested that SNPs within TP53 binding sites might be valuable biomarkers for prostate cancer outcome prediction.

Germline genetic variants associated with prostate cancer and potential relevance to clinical practice

The inherited link of prostate cancer predisposition has been supported using data from early epidemiological studies, as well as from familial and twin studies. Early linkage analyses and candidate gene approaches to identify these variants yielded mixed results. Since then, multiple genetic variants associated with prostate cancer susceptibility have now been found from genome-wide association studies (GWAS). Their clinical utility, however, remains unknown. It is recognised that collaborative efforts are needed to ensure adequate sample sizes are available to definitively investigate the genetic-clinical interactions. These could have important implications for public health as well as individualised prostate cancer management strategies. With the costs of genotyping decreasing and direct-to-consumer testing already offered for these common variants, it is envisaged that a lot of attention will be focussed in this area. These results will enable more refined risk stratification which will be important for targeting screening and prevention to higher risk groups. Ascertaining their clinical role remains an important goal for the GWAS community with international consortia now established, pooling efforts and resources to move this field forward.

Impact of interleukin-10 gene polymorphisms on survival in patients with colorectal cancer

Chronic inflammation is thought to be the leading cause of colorectal cancer, and interleukin-10 (IL10) has been identified as a potent immunomodulatory cytokine that regulates inflammatory responses in the gastrointestinal tract. Although several single nucleotide polymorphisms (SNPs) in IL10 have been associated with the risk of colorectal cancer, their prognostic significance has not been determined. Two hundred and eighty-two colorectal cancer patients were genotyped for two candidate cancer-associated SNPs in IL10. The associations of these SNPs with distant metastasis-free survival and overall survival were evaluated by Kaplan-Meier analysis and Cox regression model. The minor homozygote GG genotype of IL10 rs3021094 was significantly associated with a 3.30-fold higher risk of death compared with the TT+TG genotypes (P=0.011). The patients with IL10 rs3021094 GG genotype also had a poorer overall survival in Kaplan-Meier analysis (log-rank P=0.007) and in multivariate Cox regression model (P=0.044) adjusting for age, gender, carcinoembryonic antigen levels, tumor differentiation, stage, lymphovascular invasion, and perineural invasion. In conclusion, our results suggest that IL10 rs3021094 might be a valuable prognostic biomarker for colorectal cancer patients.

Clinical implications of microRNAs in cancer

MicroRNAs (miRNAs) are endogenously produced non-coding RNAs that serve as micromanagers by negatively regulating gene expression. MiRNAs are implicated in several biological pathways including development of neoplasia. Because altered miRNA expression is implicated in the pathobiology of various cancers, these molecules serve as potential therapeutic targets. Using miRNA mimics to restore levels of aberrantly down-regulated miRNAs or miRNA inhibitors to inactivate over-expressed miRNAs shows promise as the next generation of therapeutic strategies. Manipulation of miRNAs offers an alternative therapeutic approach for chemo- and radiation-resistant tumors. Similarly, miRNA expression patterns can be used for diagnosis and to predict prognosis and efficacy of therapy. We present here an overview of how miRNAs affect cancers, how they may be used as biomarkers, and the clinical implications of miRNAs in cancer.

Molecular markers in sex hormone pathway genes associated with the efficacy of androgen-deprivation therapy for prostate cancer

Although most advanced prostate cancer patients respond to androgen-deprivation therapy (ADT), the efficacy is widely variable. We investigated whether the host genetic variations in sex hormone pathway genes are associated with the efficacy of ADT. A cohort of 645 patients with advanced prostate cancer treated with ADT was genotyped for 18 polymorphisms across 12 key genes involved in androgen and estrogen metabolism. We found that after adjusting for known risk factors in multivariate Cox regression models, AKR1C3 rs12529 and AR-CAG repeat length remained significantly associated with prostate cancer-specific mortality (PCSM) after ADT (P ≤ 0.041). Furthermore, individuals carrying two unfavorable genotypes at these loci presented a 13.7-fold increased risk of PCSM compared with individuals carrying zero (P<0.001). Our results identify two candidate molecular markers in key genes of androgen and estrogen pathways associated with PCSM after ADT, establishing the role of pharmacogenomics in this therapy.

Genetic polymorphisms of matrix metalloproteinases and clinical outcomes in colorectal cancer patients

BACKGROUND

Colorectal cancer metastasis is a multistep process involving degradation of extracellular matrix components by proteolytic enzymes. Among them, matrix metalloproteinases (MMPs) are the principal degrading enzymes and their expressions/activities are also correlated with survival. Much research has showed the associations between genetic polymorphisms in MMPs and risk of colorectal cancer; however, their prognostic significance has not been well determined.

METHODS

We selected and genotyped 4 cancer-associated single nucleotide polymorphisms (SNPs) in a cohort of 282 colorectal cancer patients. The associations of these SNPs with distant metastasis-free survival and overall survival were evaluated by Kaplan-Meier analysis, Cox regression model, and survival tree analysis.

RESULTS

The relative risks of developing distant metastasis after curative surgery were higher in individuals with minor homozygote AA genotype than in those with GG/GA genotypes at MMP2 rs243866 (P = 0.012). Survival tree analysis also identified a higher-order genetic interaction profile consisting of MMP2 rs243866 and MMP2 rs2285053 that was significantly associated with distant metastasis-free survival (P trend = 0.016). After adjusting for possible confounders, the genetic interaction profile remained significant (P trend = 0.050).

CONCLUSIONS

These results suggest that genetic variations in the MMP2 might be potential predictors of distant metastasis-free survival after curative surgery.

MicroRNAs and prostate cancer: from preclinical research to translational oncology

The management of prostate cancer patients is rapidly changing. The extended survival seen in randomized phase III trials with new molecules has significantly enriched the therapeutic armamentarium, and ongoing clinical trials are assessing whether the integration of these active drugs within established therapeutic regimens results in a further benefit for patients. This complex scenario is raising the need for the identification and validation of biomarkers able to drive the decision-making process during the course of the disease. Compelling evidence has documented the role of microRNAs in cancer biology, and their multifaceted biological activity makes them an attractive candidate as diagnostic, prognostic, and predictive biomarkers. This review summarizes the current knowledge about microRNA deregulation in prostate cancer, how these molecules have been investigated in the clinical setting, and strategies investigators should consider for sharpening their potential.

[Prostate cancer: promising biomarkers related to aggressive disease]

BACKGROUND

Although a rapidly growing number of candidate biological markers of prognosis and/or response to specific treatments in prostate cancer, none have to date showed ability to completely prognosticate prostate cancer on evidence based urology.

OBJECTIVE

To review the pertinent literature on the issue.

ACQUISITION OF EVIDENCE

A comprehensive review of the current literature was done focusing on promising biomarkers related to aggressive prostate cancer.

SUMMARY OF EVIDENCE

Combined with the heterogeneous nature of the disease, mixed case series are the most common study design, impeding robust results and the development of an effective therapeutic strategy. Improvement in prostate cancer patient survival requires not only the identification of new therapeutic target based on detailed understanding of the biological mechanisms involved in metastatic dissemination and tumor growth but strong clinical studies as well.

CONCLUSION

Better study design involving potential markers and including well-classified and staged patients with robust methodology and adequate outcomes (mainly survival) are necessary to the field evolution.

Genetic variants in CASP3, BMP5, and IRS2 genes may influence survival in prostate cancer patients receiving androgen-deprivation therapy

Several genome-wide association studies (GWAS) have been conducted to identify the common single nucleotide polymorphisms (SNPs) that influence the risk of prostate cancer. It was hypothesized that some prostate cancer-associated SNPs might relate to the clinical outcomes in patients treated for prostate cancer using androgen-deprivation therapy (ADT). A cohort of 601 patients who have received ADT for prostate cancer was genotyped for 29 SNPs that have been associated with prostate cancer in Cancer Genetic Markers of Susceptibility GWAS, and within the genes that have been implicated in cancer. Prognostic significance of these SNPs on the disease progression, prostate cancer-specific mortality (PCSM) and all-cause mortality (ACM) after ADT were assessed by Kaplan-Meier analysis and Cox regression model. Three SNPs, namely CASP3 rs4862396, BMP5 rs3734444 and IRS2 rs7986346, were found to be closely associated with the ACM (P≤0.042), and BMP5 rs3734444 and IRS2 rs7986346 were also noted to be significantly related to the PCSM (P≤0.032) after adjusting for the known clinicopathologic predictors. Moreover, patients carrying a greater number of unfavorable genotypes at the loci of interest had a shorter time to ACM and PCSM during ADT (P for trend <0.001). Our results suggest that CASP3 rs4862396, BMP5 rs3734444 and IRS2 rs7986346 may affect the survival in patients after ADT for prostate cancer, and the analysis of these SNPs can help identify patients at higher risk of poor outcome.

Does primary androgen-deprivation therapy delay the receipt of secondary cancer therapy for localized prostate cancer?

BACKGROUND

Despite evidence that shows no survival advantage, many older patients receive primary androgen-deprivation therapy (PADT) shortly after the diagnosis of localized prostate cancer (PCa).

OBJECTIVE

This study evaluates whether the early use of PADT affects the subsequent receipt of additional palliative cancer treatments such as chemotherapy, palliative radiation therapy, or intervention for spinal cord compression or bladder outlet obstruction.

DESIGN, SETTING, AND PARTICIPANTS

This longitudinal population-based cohort study consists of Medicare patients aged ≥ 66 yr diagnosed with localized PCa from 1992 to 2006 in areas covered by the Surveillance Epidemiology and End Results (SEER) program. SEER-Medicare linked data through 2009 were used to identify the use of PADT and palliative cancer therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Instrumental variable analysis methods were used to minimize confounding effects. Confidence intervals were derived from the bootstrap estimates.

RESULTS AND LIMITATIONS

This study includes 29 775 men who did not receive local therapy for T1-T2 PCa within the first year of cancer diagnosis. Among low-risk patients (Gleason score 2-7 in 1992-2002 and Gleason score 2-6 in 2003-2006) with a median age of 78 yr and a median follow-up of 10.3 yr, PADT was associated with a 25% higher use of chemotherapy (hazard ratio [HR]: 1.25; 95% confidence interval [CI], 1.08-1.44) and a borderline higher use of any palliative cancer treatment (HR: 1.07; 95% CI, 0.97-1.19) within 10 yr of diagnosis in regions with high PADT use compared with regions with low PADT use. Because this study was limited to men >65 yr, the results may not be applicable to younger patients.

CONCLUSIONS

Early treatment of low-risk, localized PCa with PADT does not delay the receipt of subsequent palliative therapies and is associated with an increased use of chemotherapy.