A systematic review of replication studies of prostate cancer susceptibility genetic variants in high-risk men originally identified from genome-wide association studies

The role of single-nucleotide polymorphisms of the 8q24 chromosome region in patients with concomitant bladder and prostate cancer

OBJECTIVE

To assess whether single-nucleotide polymorphisms (SNPs) of the 8q24 chromosome region are associated with recurrence-free survival (RFS) after radical cystoprostatectomy (RC) in patients with concomitant bladder (BC) and prostate cancer (PC).

MATERIALS AND METHODS

A cohort of thirty-six patients treated with RC and pelvic lymph node dissection and histologically exhibited invasive BC and incidental PC. Using Sanger sequencing, a total of seven SNPs in the androgen-responsive element of the promoter region of the following genes were assessed in tumor-free lymph nodes and correlated with oncological outcomes: PSCA (rs2294008, rs2978974, rs1045531, rs3736001), MYC (rs6983267), FXBO32 (rs7830622), and MIR151A (rs14974929). The median follow-up was 26 months (range: 4-68).

RESULTS

In a dominant model, patients exhibiting rs2978974 as a minor allelic variant of the PSCA gene had worse RFS (32 vs. 75%, p = 0.015). No associations were found for the other SNPs.

CONCLUSIONS

These data suggest that the rs2978974 of the PSCA gene correlates with inferior BC-specific RFS after RC and should be further evaluated in larger studies.

Genetic Factors Associated with Prostate Cancer Conversion from Active Surveillance to Treatment

Men diagnosed with low-risk prostate cancer (PC) are increasingly electing active surveillance (AS) as their initial management strategy. While this may reduce the side effects of treatment for prostate cancer, many men on AS eventually convert to active treatment. PC is one of the most heritable cancers, and genetic factors that predispose to aggressive tumors may help distinguish men who are more likely to discontinue AS. To investigate this, we undertook a multi-institutional genome-wide association study (GWAS) of 5,222 PC patients and 1,139 other patients from replication cohorts, all of whom initially elected AS and were followed over time for the potential outcome of conversion from AS to active treatment. In the GWAS we detected 18 variants associated with conversion, 15 of which were not previously associated with PC risk. With a transcriptome-wide association study (TWAS), we found two genes associated with conversion (MAST3, p = 6.9×10-7 and GAB2, p = 2.0×10-6). Moreover, increasing values of a previously validated 269-variant genetic risk score (GRS) for PC was positively associated with conversion (e.g., comparing the highest to the two middle deciles gave a hazard ratio [HR] = 1.13; 95% Confidence Interval [CI]= 0.94-1.36); whereas, decreasing values of a 36-variant GRS for prostate-specific antigen (PSA) levels were positively associated with conversion (e.g., comparing the lowest to the two middle deciles gave a HR = 1.25; 95% CI, 1.04-1.50). These results suggest that germline genetics may help inform and individualize the decision of AS-or the intensity of monitoring on AS-versus treatment for the initial management of patients with low-risk PC.

Association of long-chain non-coding RNA GAS5 gene polymorphisms with prostate cancer risk and prognosis in Chinese Han population

BACKGROUND

To investigate the correlation between growth arrest-specific transcript 5 (GAS5) gene polymorphism and the risk and prognosis of prostate cancer in Chinese Han population.

METHODS

Sanger sequencing was used to analyze genotypes at the rs17359906 and rs1951625 loci of the GAS5 gene in 218 prostate cancer patients and 220 healthy controls. The follow-up period was from August 2016 to August 2019, and the relationships between GAS5 gene polymorphisms at the rs17359906 and rs1951625 loci and the recurrence-free survival rate of prostate cancer patients were analyzed.

RESULTS

GAS5 A-allele carriers at the rs17359906 locus were 3.44 times more likely to develop prostate cancer than G-allele carriers (95% confidence interval (CI): 2.38-4.96, P < .001). Carriers of the GAS5 A allele at the rs1951625 locus had a 1.40-fold higher risk of prostate cancer than carriers of the G allele (95% CI: 1.05-1.86, P = .027). Plasma prostate-specific antigen (PSA), body mass index (BMI), and rs17359906 and rs1951625 loci were independent risk factors for prostate cancer. GAS5 AA genotype and A-allele carriers (GA + AA) at the rs1951625 locus were significantly correlated with Gleason scores ≤7 (P < .05). GAS5 genes rs17359906 G > A and rs1951625 G > A were associated with high plasma PSA levels. The recurrence-free survival rate of patients with prostate cancer with AA genotype at the rs17359906 locus of GAS5 (66.67%) was significantly lower than that of the GA genotype (76.47%), whereas the GG genotype was the highest (91.96%), and the difference was statistically significant (P = .002). The recurrence-free survival rate of patients with prostate cancer with the AA genotype at the rs1951625 locus of GAS5 (75.00%) was significantly lower than that of the GA genotype (81.82%), whereas the GG genotype was the highest (87.76%) with a statistically significant difference (P = .025).

CONCLUSION

GAS5 rs17359906 G > A and rs1951625 G > A are significantly associated with an increased risk of prostate cancer and a reduction in three-year relapse-free survival.

Data-driven translational prostate cancer research: from biomarker discovery to clinical decision

Prostate cancer (PCa) is a common malignant tumor with increasing incidence and high heterogeneity among males worldwide. In the era of big data and artificial intelligence, the paradigm of biomarker discovery is shifting from traditional experimental and small data-based identification toward big data-driven and systems-level screening. Complex interactions between genetic factors and environmental effects provide opportunities for systems modeling of PCa genesis and evolution. We hereby review the current research frontiers in informatics for PCa clinical translation. First, the heterogeneity and complexity in PCa development and clinical theranostics are introduced to raise the concern for PCa systems biology studies. Then biomarkers and risk factors ranging from molecular alternations to clinical phenotype and lifestyle changes are explicated for PCa personalized management. Methodologies and applications for multi-dimensional data integration and computational modeling are discussed. The future perspectives and challenges for PCa systems medicine and holistic healthcare are finally provided.

HIF1α promotes prostate cancer progression by increasing ATG5 expression

Prostate cancer (PCa) is the most frequently diagnosed cancer among men. However, the major modifiable risk factors for PCa are poorly known and its specific mechanism of progression remains unclear. Here we reported that, in prostate cancer cells, the autophagy level was elevated under hypoxic condition, as well as the mRNA and protein level of ATG5, which is an important gene related to autophagy. Furthermore, we found HIF1α could directly bind to the promoter of ATG5 and promote the expression of ATG5 on transcriptional level by luciferase assay and ChIP assay. Intriguingly, overexpression of HIF1α by HIF1α-M could increase tumor size and the effect could be abolished by knockdown ATG5 by si-ATG5 in BALB/cA-nu/nu nude mice. Importantly, HIF1α could also promote the metastasis of PC-3 cells by upregulating the ATG5 and autophagy level and knockdown ATG5 and inhibition autophagy both could abolish the effect of overexpression of HIF1α on the migration of PC-3 cells. Taken together, our results, for the first time, proved that HIF1α could promote the proliferation and migration of PC-3 cells by direct upregulating ATG5 and autophagy level in PC-3 prostate cancer cells. Our findings not only provide new perspective for the relationship between hypoxia and autophagy, but also add new potential therapeutic regimens for the treatment of prostate cancers.

Statin use linked with a decrease in the conversion from high-grade prostatic intraepithelial neoplasia (HGPIN) to prostate cancer

The roles of obesity, metabolic dysregulation and systemic inflammation to advance prostate carcinogenesis are unclear. This study investigates metabolic and inflammatory factors in the transition from high-grade prostatic intraepithelial neoplasia (HGPIN) to prostate cancer (PC). We prospectively followed 160 men diagnosed with HGPIN at biopsy and therefore at high-risk and clinically monitored for PC. Analyses investigated body mass index (BMI), waist circumference, waist-hip ratio (WHR), height, fat mass, lean mass percent body fat, NSAIDs, statins, metformin, diabetes, hypertension, hypercholesterolemia representing metabolic dysregulation on the risk of a PC diagnosis during follow-up. Systemic inflammation was estimated through measurement of 13 plasma cytokine levels. Statin use was significantly linked with overall PC at follow-up [odds ratio (OR) = 0.45, (0.23, 0.91), P = 0.03], with a somewhat stronger link with high-grade [OR = 0.39, (0.15, 1.04), P = 0.06] PC compared with low-grade PC [OR = 0.50, (0.23, 1.12), P = 0.09]. Non-statin cholesterol-lowering medications, BMI, WHR, diabetes, hypertension and percent body fat were not significantly associated with PC. Although blood IL-12p70, IL-2 and IL-1β levels were significantly lower among statin users, inflammatory markers were not significantly linked with PC and did not explain the observed relationship between statins and lower PC risk. In summary, this prospective study of HGPIN patients at high risk for PC finds that statin use was significantly associated with reduced risk of PC detection at follow-up. Systemic markers of inflammation did not mediate this association, suggesting that statins affect PC progression through alternative pathways.

Genetic associations of T cell cancer immune response with tumor aggressiveness in localized prostate cancer patients and disease reclassification in an active surveillance cohort

Determining prostate cancer (PCa) aggressiveness and reclassification are critical events during the treatment of localized disease and for patients undergoing active surveillance (AS). Since T cells play major roles in cancer surveillance and elimination, we aimed to identify genetic biomarkers related to T cell cancer immune response which are predictive of aggressiveness and reclassification risks in localized PCa. The genotypes of 3,586 single nucleotide polymorphisms (SNPs) from T cell cancer immune response pathways were analyzed in 1762 patients with localized disease and 393 who elected AS. The aggressiveness of PCa was defined according to pathological Gleason score (GS) and D'Amico criteria. PCa reclassification was defined according to changes in GS or tumor characteristics during subsequent surveillance biopsies. Functional characterization and analysis of immune phenotypes were also performed. In the localized PCa cohort, seven SNPs were significantly associated with the risk of aggressive disease. In the AS cohort, another eight SNPs were identified as predictors for aggressiveness and reclassification. Rs1687016 of PSMB8 was the most significant predictor of reclassification. Cumulative analysis showed that a genetic score based on the identified SNPs could significantly predict risk of D'Amico high risk disease (P-trend = 2.4E-09), GS4 + 3 disease (P-trend = 1.3E-04), biochemical recurrence (P-trend = 0.01) and reclassification (P-trend = 0.01). In addition, the rs34309 variant was associated with functional somatic mutations in the PI3K/PTEN/AKT/MTOR pathway and tumor lymphocyte infiltration. Our study provides plausible evidence that genetic variations in T cell cancer immune response can influence risks of aggressiveness and reclassification in localized PCa, which may lead to additional biological insight into these outcomes. Abbreviations: PCa, prostate cancer; AS, active surveillance; GS, Gleason score; PSA, prostate specific antigen; TCGA, The Cancer Genome Atlas; SNP, single nucleotide polymorphisms; UFG, unfavorable genotype.

Success and failure in replication of genotype-phenotype associations: How does replication help in understanding the genetic basis of phenotypic variation in outbred populations?

Recent developments in sequencing technologies have facilitated genomewide mapping of phenotypic variation in natural populations. Such mapping efforts face a number of challenges potentially leading to low reproducibility. However, reproducible research forms the basis of scientific progress. We here discuss the options for replication and the reasons for potential nonreproducibility. We then review the evidence for reproducible quantitative trait loci (QTL) with a focus on natural animal populations. Existing case studies of replication fall into three categories: (i) traits that have been mapped to major effect loci (including chromosomal inversion and supergenes) by independent research teams; (ii) QTL fine-mapped in discovery populations; and (iii) attempts to replicate QTL across multiple populations. Major effect loci, in particular those associated with inversions, have been successfully replicated in several cases within and across populations. Beyond such major effect variants, replication has been more successful within than across populations, suggesting that QTL discovered in natural populations may often be population-specific. This suggests that biological causes (differences in linkage patterns, allele frequencies or context-dependencies of QTL) contribute to nonreproducibility. Evidence from other fields, notably animal breeding and QTL mapping in humans, suggests that a significant fraction of QTL is indeed reproducible in direction and magnitude at least within populations. However, there is also a large number of QTL that cannot be easily reproduced. We put forward that more studies should explicitly address the causes and context-dependencies of QTL signals, in particular to disentangle linkage differences, allele frequency differences and gene-by-environment interactions as biological causes of nonreproducibility of QTL, especially between populations.

PSCA rs1045531 Polymorphism and the Risk of Prostate Cancer in a Chinese Population Undergoing Prostate Biopsy

Background and Purpose:

This study explored the association between a single-nucleotide polymorphism of prostate stem cell antigen and prostate cancer in Chinese patients undergoing prostate biopsy.

Materials and Methods:

DNA from 416 patients undergoing prostate biopsy was typed for the prostate stem cell antigen rs1045531 single-nucleotide polymorphism. The frequency of the rs1045531 polymorphism in patients with prostate cancer and in patients with benign prostatic hyperplasia was compared. Associations between the polymorphism and the risk of prostate cancer, prostate special antigen, Gleason score, and clinical stage were analyzed.

Results:

Statistically significant differences in the distribution of the rs1045531 genotypes and alleles were found between prostate cancer and benign prostatic hyperplasia in patients undergoing prostate biopsy (P = .035 and .046, respectively). We found that the rs1045531 AC genotype was significantly associated with a high risk of prostate cancer in the heterozygote model (AC vs CC; odds ratio = 2.383, 95% confidence interval: 1.198-4.741, χ² = 6.229, P = .013) and the dominant model (AA/AC vs CC; odds ratio = 2.169, 95% confidence interval: 1.112-4.229, χ² = 5.228, P = .022). However, susceptibility of prostate cancer was decreased in the homozygote model (AA vs CC; odds ratio = 0.828, 95% confidence interval: 0.143-4.805, P = .601). When considering clinical factors, the rs1045531 showed an association with prostate special antigen of 10 ng/mL or greater, a Gleason score of 7 or greater, and a size of T2 or greater.

Conclusion:

Men with the rs1045531 AC genotype of prostate stem cell antigen were at higher risk of prostate cancer in Chinese patients undergoing prostate biopsy.

Rethinking ovarian cancer genomics: where genome-wide association studies stand?

Genome-wide association studies (GWAS) allow the finding of genetic variants associated with several traits. Regarding ovarian cancer (OC), 15 GWAS have been conducted since 2009, with the discovery of 49 SNPs associated with disease susceptibility and 46 with impact in the clinical outcome of patients (p < 5.00 × 10-2). Among them, 14 variants reached the genome-wide significance (p < 5.00 × 10−8). Despite the results obtained, they should be validated in independent sets. So far, five validation studies have been conducted which could confirm the association of 12 OC susceptibility SNPs. Consequently, post-GWAS studies are crucial unravel the biological plausibility of GWAS’ findings and the allelic spectrum of OC.

A Single Nucleotide Polymorphism in HPGD Gene Is Associated with Prostate Cancer Risk

Introduction: The HPGD gene was associated with some cancers, such as colorectal, breast, prostate, and bladder. However, detailed role of 15-hydroxyprostaglandin dehydrogenase (HPGD) gene remain unclear in prostate cancer. The study was to investigate the correlation between rs8752 that located in the 3'untranslated region (UTR) of the 15-hydroxyprostaglandin dehydrogenase (HPGD) gene and prostate cancer (PCa) risk.

Materials and Methods: 109 patients from the First Affiliate Hospital of Soochow University were recruited. According to the results of pathologic diagnosis, all patients were divided into two groups (prostate cancer and benign prostatic hyperplasia). The single-nucleotide polymorphism (SNP) rs8752 was genotyped in all samples by direct sequencing.

Results: 54 prostate cancer and 55 BPH patients were included with a median age of 70.41 and 67.62 years, respectively. No statistically significant difference between two groups in patient criteria. The frequency of the GG homozygote and AG+GG genotype were 37.74% and 62.26% in 54 prostate cancer samples, while in 55BPH patients, values were 62.50% and 37.50%. Compared with the GG genotype, the combined GA+AA genotypes had a significantly higher risk of prostate cancer (OR = 2.750; 95% CI: 1.266-5.971, p = 0.011). Furthermore, the risk effect was obtained in subgroups of PCa patient group, the AA+AG genotypes significantly associated with the higher Gleason score samples (AA+AG vs GG: OR = 3.50, 95%CI = 1.106-11.072, p = 0.033) and the risk of pathological stage (AA+AG vs GG: OR = 4.00, 95%CI = 1.253-12.767, p = 0.019).

Conclusions: rs8752 in the 3'untranslated region (UTR) of the 15-hydroxyprostaglandin dehydrogenase (HPGD) gene was found to be responsible for the susceptibility to prostate cancer in Chinese individuals.

Codon-level co-occurrences of germline variants and somatic mutations in cancer are rare but often lead to incorrect variant annotation and underestimated impact prediction

Cancer cells explore a broad mutational landscape, bringing the possibility that tumor-specific somatic mutations could fall in the same codons as germline SNVs and leverage their presence to produce substitutions with a larger impact on protein function. While multiple, temporally consecutive mutations to the same codon have in the past been detected in the germline, this phenomenon has not yet been explored in the context of germline-somatic variant co-occurrences during cancer development. We examined germline context at somatic mutation sites for 1395 patients across four cancer cohorts (breast, skin, colon, and head and neck) and found 392 codon-level co-occurrences between germline and somatic variants, including over a dozen in well-known cancer genes. We found that for the majority of these co-occurrence events, traditional somatic calling led to an inaccurate representation of the protein site and a significantly lower predicted impact on protein fitness. We conclude that these events often lead to imprecise annotation of somatic variants but do not appear to be a frequent source of driver events during cancer development.

Prostate Cancer Genetics: Variation by Race, Ethnicity, and Geography

Prostate cancer rates vary substantially by race, ethnicity, and geography. These disparities can be explained by variation in access to screening and treatment, variation in exposure to prostate cancer risk factors, and variation in the underlying biology of prostate carcinogenesis (including genomic propensity of some groups to develop biologically aggressive disease). It is clear that access to screening and access to treatment are critical influencing factors of prostate cancer rates; yet, even among geographically diverse populations with similar access to care (eg, low- and medium-income countries), African descent men have higher prostate cancer rates and poorer prognosis. To date, the proportion of prostate cancer that can be explained by environmental exposures is small, and the effect of these factors across different racial, ethnic, or geographical populations is poorly understood. In contrast, prostate cancer has one of the highest heritabilities of all major cancers. Numerous genetic susceptibility markers have been identified from family-based studies, candidate gene association studies, and genome-wide association studies. Some prostate cancer loci, including the risk loci found at chromosome 8q24, have consistent effects in all groups studied to date. However, replication of many susceptibility loci across race, ethnicity, and geography remains limited, and additional studies in certain populations (particularly in men of African descent) are needed to better understand the underlying genetic basis of prostate cancer.

Rare Paravertebral and Skull Base Metastases in Prostate Cancer

Prostate cancer is the most commonly diagnosed visceral cancer in the United States. A majority of cases exhibit an insidious course and nonaggressive tumor behavior. Prostate cancer can manifest as lesions which remain localized, regionally invading or metastasize to lymph nodes, bones, and lungs. Here, we report a unique case of metastatic prostate cancer to the right upper mediastinum, presenting as a paravertebral mass within 2 years of initial tissue diagnosis. Paravertebral spread has not been described for prostate cancer, and herein, we discuss the clinical presentation, diagnostic workup, and possible therapeutic options available in light of the literature.

Polymorphisms in HLA Class II Genes Are Associated With Susceptibility to Staphylococcus aureus Infection in a White Population

BACKGROUND

Staphylococcus aureus can cause life-threatening infections. Human susceptibility to S. aureus infection may be influenced by host genetic variation.

METHODS

A genome-wide association study (GWAS) in a large health plan-based cohort included biologic specimens from 4701 culture-confirmed S. aureus cases and 45 344 matched controls; 584 535 single-nucleotide polymorphisms (SNPs) were genotyped on an array specific to individuals of European ancestry. Coverage was increased by imputation of >25 million common SNPs, using the 1000 Genomes Reference panel. In addition, human leukocyte antigen (HLA) serotypes were also imputed.

RESULTS

Logistic regression analysis, performed under the assumption of an additive genetic model, revealed several imputed SNPs (eg, rs115231074: odds ratio [OR], 1.22 [P = 1.3 × 10(-10)]; rs35079132: OR, 1.24 [P = 3.8 × 10(-8)]) achieving genome-wide significance on chromosome 6 in the HLA class II region. One adjacent genotyped SNP was nearly genome-wide significant (rs4321864: OR, 1.13; P = 8.8 × 10(-8)). These polymorphisms are located near the genes encoding HLA-DRA and HLA-DRB1. Results of further logistic regression analysis, in which the most significant GWAS SNPs were conditioned on HLA-DRB1*04 serotype, showed additional support for the strength of association between HLA class II genetic variants and S. aureus infection.

CONCLUSIONS

Our study results are the first reported evidence of human genetic susceptibility to S. aureus infection.

Cancer Genomics: Diversity and Disparity Across Ethnicity and Geography

Ethnic and geographic differences in cancer incidence, prognosis, and treatment outcomes can be attributed to diversity in the inherited (germline) and somatic genome. Although international large-scale sequencing efforts are beginning to unravel the genomic underpinnings of cancer traits, much remains to be known about the underlying mechanisms and determinants of genomic diversity. Carcinogenesis is a dynamic, complex phenomenon representing the interplay between genetic and environmental factors that results in divergent phenotypes across ethnicities and geography. For example, compared with whites, there is a higher incidence of prostate cancer among Africans and African Americans, and the disease is generally more aggressive and fatal. Genome-wide association studies have identified germline susceptibility loci that may account for differences between the African and non-African patients, but the lack of availability of appropriate cohorts for replication studies and the incomplete understanding of genomic architecture across populations pose major limitations. We further discuss the transformative potential of routine diagnostic evaluation for actionable somatic alterations, using lung cancer as an example, highlighting implications of population disparities, current hurdles in implementation, and the far-reaching potential of clinical genomics in enhancing cancer prevention, diagnosis, and treatment. As we enter the era of precision cancer medicine, a concerted multinational effort is key to addressing population and genomic diversity as well as overcoming barriers and geographical disparities in research and health care delivery.

Associations Between iCOGS Single Nucleotide Polymorphisms and Upgrading in Both Surgical and Active Surveillance Cohorts of Men with Prostate Cancer

BACKGROUND

Associations have been documented recently between some of the 23 single nucleotide polymorphisms newly discovered with the Collaborative Oncological Gene-environment Study iCOGS array that indicate prostate cancer (PCa) risk and aspects of disease aggressiveness. The utility of these iCOGS SNPs remains to be determined in active surveillance (AS).

OBJECTIVE

To determine associations between iCOGS SNPs and upgrading among men who underwent surgical treatment and AS for low-risk PCa.

DESIGN, SETTING, AND PARTICIPANTS

The genotypes of the 23 iCOGS SNPs were determined for all white subjects with biopsy Gleason score (GS) 6 including 950 men who underwent definitive treatment with surgery and 209 men who elected AS. The clinical and pathologic characteristics were documented for all subjects.

OUTCOME MEASURES AND STATISTICAL ANALYSIS

Men who underwent surgery were grouped according to their pathologic GS (upgraded was defined as GS ≥7; nonupgraded remained GS 6). Men who were enrolled in AS were also grouped according to their GS on subsequent surveillance biopsies. Statistical analyses were performed comparing the genotypes between the upgraded and nonupgraded groups.

RESULTS AND LIMITATIONS

Overall, 31% and 34% of men were upgraded in the surgery and AS cohorts, respectively. Three iCOGS SNPs were significantly associated with the risk of upgrading in the surgical cohort. After correction for multiple testing, only rs11568818 on chromosome 11q22 remained significantly associated with upgrading. Assessment of this allele in the AS cohort reveals that it was present at noteworthy higher frequencies in men with high-grade disease on surveillance biopsies compared with nonupgraded men (p=0.003). This study was primarily limited by the homogeneous patient population.

CONCLUSIONS

This is the first report of a SNP on chromosome 11q22 associated with higher grade disease in a surgical cohort that is also validated for eventual upgrading in a prospective AS cohort.

PATIENT SUMMARY

We examined the relationship between a group of genetic markers and prostate cancer (PCa) aggressiveness in a group of patients who underwent surgery for PCa and a group of patients who were enrolled in active surveillance. We found that these genetic markers helped predict which patients had more aggressive disease in both groups.

A genetic-based approach to personalized prostate cancer screening and treatment

PURPOSE OF REVIEW

Recent advances in sequencing technologies have allowed for the identification of genetic variants within germline DNA that can explain a significant portion of the genetic underpinnings of prostate cancer. Despite evidence suggesting that these genetic variants can be used for improved risk stratification, they have not yet been routinely incorporated into routine clinical practice. This review highlights their potential utility in prostate cancer screening.

RECENT FINDINGS

There are now almost 100 genetic variants, called single nucleotide polymorphisms (SNPs) that have been recently found to be associated with the risk of developing prostate cancer. In addition, some of these prostate cancer risk SNPs have also been found to influence prostate specific antigen (PSA) expression levels and potentially aggressive disease.

SUMMARY

Incorporation of panels of prostate cancer risk SNPs into clinical practice offers potential to provide improvements in patient selection for prostate cancer screening; PSA interpretation (e.g. by correcting for the presence of SNPs that influence PSA expression levels; decision for biopsy (using prostate cancer risk SNPs); and possibly the decision for treatment. A proposed clinical algorithm incorporating these prostate cancer risk SNPs is discussed.

Associations of prostate cancer risk variants with disease aggressiveness: results of the NCI-SPORE Genetics Working Group analysis of 18,343 cases

Genetic studies have identified single nucleotide polymorphisms (SNPs) associated with the risk of prostate cancer (PC). It remains unclear whether such genetic variants are associated with disease aggressiveness. The NCI-SPORE Genetics Working Group retrospectively collected clinicopathologic information and genotype data for 36 SNPs which at the time had been validated to be associated with PC risk from 25,674 cases with PC. Cases were grouped according to race, Gleason score (Gleason ≤ 6, 7, ≥ 8) and aggressiveness (non-aggressive, intermediate, and aggressive disease). Statistical analyses were used to compare the frequency of the SNPs between different disease cohorts. After adjusting for multiple testing, only PC-risk SNP rs2735839 (G) was significantly and inversely associated with aggressive (OR = 0.77; 95 % CI 0.69-0.87) and high-grade disease (OR = 0.77; 95 % CI 0.68-0.86) in European men. Similar associations with aggressive (OR = 0.72; 95 % CI 0.58-0.89) and high-grade disease (OR = 0.69; 95 % CI 0.54-0.87) were documented in African-American subjects. The G allele of rs2735839 was associated with disease aggressiveness even at low PSA levels (<4.0 ng/mL) in both European and African-American men. Our results provide further support that a PC-risk SNP rs2735839 near the KLK3 gene on chromosome 19q13 may be associated with aggressive and high-grade PC. Future prospectively designed, case-case GWAS are needed to identify additional SNPs associated with PC aggressiveness.

rs10505474 and rs7837328 at 8q24 cumulatively confer risk of prostate cancer in Northern Han Chinese

AIMS

Genome-wide association studies (GWAS) have identified several risk variants for prostate cancer (pCa) mainly in Europeans, which need to be further verified in other racial groups. We selected six previously identified variants as candidates and to define the association with PCa in Northern Han Chinese.

METHODS

749 subjects from Beijing and Tianjin in Northern China were included. Six variants (rs10505474, rs7837328, rs4242384, rs7813, rs486907 and rs1058205) were genotyped by high resolution melting (HRM) assays. The individual and cumulative contribution for of the risk of PCa and clinical covariates were analyzed.

RESULTS

Among the six candidate variants, only rs10505474, and rs7837328, both locating at 8q24 region, were associated with PCa in our population.rs10505474 (A) was associated with PCa (ORrecessive= 1.56, p=0.006); and rs7837328 (A) was associated with PCa (ORdominant= 1.38, p=0.042/ORrecessive=1.99, p=0.003). Moreover, we observed a cumulative effects between them (ptrend=2.58?10-5). The joint population attributable risk showed the two variants might account for 71.85% of PCa risk. In addition, we found the homozygotes of rs10505474 (A) and rs7837328 (A) were associated with PCa clinical covariants (age at onset, tumor stage, respectively) (page=0.046, Ptumorstage =0.048).

CONCLUSION

rs10505474 (A) and rs7387328 (A) at 8q24 are associated with PCa and cumulatively confer risk, suggesting the two variations could determine susceptibility to PCa in the Northern Chinese Han population.

Genetically adjusted prostate-specific antigen values may prevent delayed biopsies in African-American men

OBJECTIVE

To evaluate whether genetic correction using the genetic variants prostate-specific antigen (PSA)-single nucleotide polymorphisms (SNPs) could reduce potentially unnecessary and/or delayed biopsies in African-American men.

SUBJECTS AND METHODS

We compared the genotypes of four PSA-SNPs between 964 Caucasian and 363 African-American men without known prostate cancer (PCa). We adjusted the PSA values based on an individual's PSA-SNP carrier status, and calculated the percentage of men that would meet commonly used PSA thresholds for biopsy (≥ 2.5 or ≥ 4.0 ng/mL) before and after genetic correction. Potentially unnecessary and delayed biopsies were defined as those men who were below and above the biopsy threshold after genetic correction, respectively.

RESULTS

Overall, 349 (96.1%) and 354 (97.5%) African-American men had measured PSA levels <2.5 and <4.0 ng/mL. Genetic correction in African-American men did not avoid any potentially unnecessary biopsies, but resulted in a significant (P < 0.001) reduction in potentially delayed biopsies by 2.5% and 3.9%, based on the biopsy threshold level.

CONCLUSIONS

There are significant differences in the influence of the PSA-SNPs between African-American and Caucasian men without known PCa, as genetic correction resulted in an increased proportion of African-American men crossing the threshold for biopsy. These results raise the question of whether genetic differences in PSA might contribute to delayed PCa diagnosis in African-American men.

8q24 risk alleles and prostate cancer in African-Barbadian men

BACKGROUND

African American men (AA) exhibit a disproportionate share of prostate cancer (PRCA) incidence, morbidity, and mortality. Several genetic association studies have implicated select 8q24 loci in PRCA risk in AA. The objective of this investigation is to evaluate the association between previously reported 8q24 risk alleles and PRCA in African-Barbadian (AB) men known to have high rates of PRCA.

METHODS

Ten previously reported candidate tag SNPs were genotyped and/or imputed in the 8q24 region in 532 AB men with PRCA and 513 AB controls from the Prostate Cancer in a Black Population (PCBP) study.

RESULTS

Rs2124036 was significant in AB men, (OR = 2.7, 95% CI (1.3-5.3), P = 0.005, Empirical (max (T), corrected for multiple testing) P = 0.03) for the homozygous C/C genotype. Only a single SNP from this region remained statistically significant in our analysis of our AB population. These results may indicate the presence of a founder effect or due to the chosen SNPs not tagging an ancestral haplotype bearing the 8q24 risk allele(s) in this population or could reflect inadequate power to detect an association. We conducted a meta-analysis including our AB population along with two additional African Caribbean populations from Tobago and Jamaica for SNPs rs16901979 and rs1447295. Meta-analysis results were most significant for rs16901979 A allele (Z score 2.73; P = 0.006) with a summary OR = 1.31 (95% CI: 1.09-1.58).

CONCLUSIONS

Additional studies are needed to provide deeper genotype coverage to further interrogate the 8q24 region to understand its contribution to PRCA in this population.

A rare 8q24 single nucleotide polymorphism (SNP) predisposes North American men to prostate cancer and possibly more aggressive disease

OBJECTIVE

To assess the frequency of a novel prostate cancer-associated single nucleotide polymorphism (SNP), rs188140481, in a North American population and to evaluate the clinical significance of this variant including annotated prostatectomy pathology.

PATIENTS/SUBJECTS AND METHODS

We examined the frequency of the minor allele at rs188140481 in 4299 North American men including 1979 men with prostate cancer and 2320 healthy volunteers. We compared the clinicopathological features of prostate cancer between carriers and non-carriers of the SNP.

RESULTS

The rs188140481[A] SNP was present in 1.6% of the cohort; it was significantly more likely to be carried by men with prostate cancer than healthy controls (odds ratio 3.14; 95% confidence interval [CI] 1.85-5.35). After adjusting for age and PSA levels, carriers were found to be 6.73-fold (95% CI 1.69-26.76) more likely to develop prostate cancer than non-carriers. Age at diagnosis, frequency of a positive family history of prostate cancer, and biochemical recurrence rates were similar between SNP carriers and non-carriers. Patients with the SNP had a proportionately higher frequency of stage ≥T2c disease (29.5% vs 20.1%; P = 0.13), Gleason ≥8 tumours (13.3% vs 6.5%; P = 0.10), and extracapsular extension (28.9% vs 18.8%; P = 0.12) compared with non-carriers.

CONCLUSIONS

rs188140481[A] is a rare SNP that confers greater risk of prostate cancer compared with SNPs identified by genome-wide association studies. Because of its low frequency, larger studies are needed to validate the prognostic significance of this locus, and associations with adverse pathology.

FGF23: mediator of poor prognosis in a sizeable subgroup of patients with castration-resistant prostate cancer presenting with severe hypophosphatemia?

Castration-resistant prostate cancer (CRPC) is an advanced and incurable stage of the second most frequently diagnosed malignancy in men globally. Current treatment options improve survival modestly but eventually fail due to intrinsic or acquired therapeutic resistance. A hypothesis is presented wherein circulating levels of fibroblast growth factor 23 (FGF23), an endocrine member of the fibroblast growth factor family with phosphaturic properties, are proposed as a prognostic and predictive marker to identify CRPC patients with poor prognosis that are amenable to FGF23 antibody therapy (FGF23i) or treatment with fibroblast growth factor receptor inhibitors (FGFRi). With respect to the latter, FGF23 may also serve as a pharmacodynamic marker enabling individualized FGFRi dosing. We recently discovered that the development of severe and sustained hypophosphatemia in CRPC patients undergoing zoledronic acid therapy for bone metastases was associated with markedly worse prognosis compared to patients without or with only mild and transient hypophosphatemia. Severe hypophosphatemia is a typical manifestation of tumor-induced hypophosphatemic osteomalacia (TIO), a paraneoplastic condition mediated by FGF23 overexpression in most instances. While the postulated tumor-promoting role of FGF23 in CRPC or other malignancies has not yet been studied, several lines of evidence suggest that FGF23 may mediate both severe hypophosphatemia (via its endocrine properties) and aggressive CRPC behavior (via autocrine and paracrine activities): (i) FGF23 and the necessary signalling machinery (i.e. members of the fibroblast growth factor receptor [FGFR] family and the essential co-receptor α-KLOTHO [KL]) are highly expressed in a sizeable subgroup of CRPC patients; (ii) FGF/FGFR signalling plays important roles in prostate cancer; (iii) FGF23 can induce its own expression via a positive autocrine feedback loop involving FGFR1; and (iv) this positive feedback loop may be triggered by bone-targeted therapies frequently used for the treatment of CRPC-associated bone metastases. While there is a lack of personalized treatment strategies in the management of CRPC to date, FGF23 targeted therapy has the potential to fill this unmet clinical need in the not-so-distant future. In fact, FGFRi are currently in advanced clinical testing for a number of malignancies such as kidney and lung cancer, but there is a lack of conclusive data on FGFRi therapy in patients selected for FGF/FGFR pathway activation.

Increased association of the ERG oncoprotein expression in advanced stages of prostate cancer in Filipinos

BACKGROUND

Filipinos with prostate cancer (CaP) are at increased risk of harboring advanced stages and lower survival rates compared to other Asians. This study aims to investigate prevalence of ETS-related gene (ERG) oncoprotein overexpression in Filipinos as surrogate of TMPRSS2-ERG gene fusions, using a highly specific monoclonal antibody (ERG-MAb), and conduct the first attempt to study the role of genetic alterations in the aggressive tumor biologic behaviour of CaP among Filipinos.

METHODS

This case-matched, case-control retrospective study evaluated ERG expression in Filipino patients diagnosed with CaP and its effect on stage and Gleason grade of their disease. Men who underwent radical prostatectomy for organ-confined disease at the University of the Philippines-Philippine General Hospital (UP-PGH) comprised the organ-confined cohort. Age-matched adults who had trans-rectal ultrasound-guided prostate (TRUSP) biopsy or trans-urethral resection of the prostate (TURP) with bilateral orchiectomy for T4 or stage IV CaP composed the advanced disease cohort.

RESULTS

Overall ERG expression frequency of 23.08% (N = 104) was demonstrated, with a higher rate observed in the advanced disease cohort (32.69%) compared to the organ-confined group (13.46%). Furthermore, ERG overexpression was only detected among intermediate and high-risk tumors. A high-specificity (98.08%) of the ERG-MAb for malignant prostatic cells was likewise demonstrated.

CONCLUSIONS

In contrast to higher ERG frequency in Western countries, it is much lower in Filipino CaP, which is similar to lower rates noted from other Asian countries. The 98.08% specificity of ERG oncoprotein for prostate tumor cells combined with its increased association in advanced disease, suggests for prognostic potential of ERG that may aid clinicians in treatment decisions for Filipino CaP patients.

Prostate cancer risk alleles are associated with prostate cancer volume and prostate size

PURPOSE

Genome-wide association studies have identified an increasing number of single nucleotide polymorphisms associated with prostate cancer risk. Some of these genetic variants are also associated with serum prostate specific antigen levels and lower urinary tract symptoms, raising the question of whether they are truly prostate cancer biomarkers or simply lead to detection bias. Therefore, we determined whether single nucleotide polymorphisms associated with prostate cancer risk are more strongly associated with tumor or prostate volume.

MATERIALS AND METHODS

The genotypes of 38 validated prostate cancer risk single nucleotide polymorphisms were determined in 1,321 white men who underwent radical prostatectomy. Univariate and multivariate analyses were performed to compare the relationship of single nucleotide polymorphism frequency with total prostate and tumor volumes.

RESULTS

On multivariate analysis 2 single nucleotide polymorphisms on chromosome 8q24, rs16901979 (A) and rs6983267 (G), were significantly associated with increased tumor volume (p=0.01 and 0.02, respectively). In contrast, rs17632542 (T) near the PSA gene on 19q13 was associated with significantly lower tumor volume and rs10788160 (A) on 10q26 was associated with significantly larger prostate volume (p=0.02 and 0.01, respectively).

CONCLUSIONS

Analysis of 38 single nucleotide polymorphisms associated with prostate cancer risk revealed a significant association between several on chromosome 8q24 and increased tumor volume but not prostate volume. This suggests that they are bona fide markers of prostate cancer susceptibility and possibly more aggressive disease. Other prostate cancer risk alleles are associated with prostate specific antigen and increased prostate or decreased tumor volume, suggesting detection bias due to their phenotypic influence.

Validation of six genetic determinants of susceptibility to estrogen-induced mammary cancer in the rat and assessment of their relevance to breast cancer risk in humans

When treated with 17β-estradiol, female ACI rats (Rattus norvegicus) rapidly develop mammary cancers that share multiple phenotypes with luminal breast cancers. Seven distinct quantitative trait loci that harbor genetic determinants of susceptibility to 17β-estradiol−induced mammary cancer have been mapped in reciprocal intercrosses between susceptible ACI rats and resistant Brown Norway (BN) rats. A panel of unique congenic rat strains has now been generated and characterized to confirm the existence of these quantitative trait loci, designated Emca3 through Emca9, and to quantify their individual effects on susceptibility to 17β-estradiol−induced mammary cancer. Each congenic strain carries BN alleles spanning an individual Emca locus, introgressed onto the ACI genetic background. Data presented herein indicate that BN alleles at Emca3, Emca4, Emca5, Emca6, and Emca9 reduce susceptibility to 17β-estradiol−induced mammary cancer, whereas BN alleles at Emca7 increase susceptibility, thereby confirming the previous interval mapping data. All of these Emca loci are orthologous to regions of the human genome that have been demonstrated in genome-wide association studies to harbor genetic variants that influence breast cancer risk. Moreover, four of the Emca loci are orthologous to loci in humans that have been associated with mammographic breast density, a biomarker of breast cancer risk. This study further establishes the relevance of the ACI and derived congenic rat models of 17β-estradiol−induced mammary cancer for defining the genetic bases of breast cancer susceptibility and elucidating the mechanisms through which 17β-estradiol contributes to breast cancer development.

Prostate cancer genetic-susceptibility locus on chromosome 20q13 is amplified and coupled to androgen receptor-regulation in metastatic tumors

The 20q13 chromosomal region has been previously identified as the hereditary prostate cancer genetic-susceptibility locus on chromosome 20 (HPC20). In this study, the 20q13 region was shown to be frequently co-amplified with the androgen receptor (AR) in metastatic prostate cancer. Furthermore, the AR signaling axis, which plays an essential role in the pathogenesis of prostate cancer, was demonstrated to be central to the regulation of the 20q13 common amplified region (CAR). High-resolution mapping analyses revealed hot spots of AR recruitment to response elements in the vicinity of most genes located on the 20q13 CAR. Moreover, amplification of AR significantly co-occurred with CAR amplification on 20q13 and it was confirmed that the majority of AR-bound genes on the 20q13 CAR were indeed regulated by androgens. These data reveal that amplification of the AR is tightly linked to amplification of the AR-regulated CAR region on 20q13. These results suggest that the cross-talk between gene amplification and gene transcription is an important step in the development of castration-resistant metastatic disease.

IMPLICATIONS

These novel results are a noteworthy example of the cross-talk between gene amplification and gene transcription in the development of advanced prostate cancer.

Genetic variations of α -methylacyl-CoA racemase are associated with sporadic prostate cancer risk in ethnically homogenous Koreans

Background. To assess if the variants of (R)-alpha-methyl-CoA racemase (AMACR) gene would be associated with the risk of sporadic prostate cancer in ethnically homogenous Koreans. Materials and Methods. We enrolled 194 patients with prostate cancer and 169 healthy controls. A total of 17 single nucleotide polymorphisms of the AMACR gene were selected. The distribution of each genotype and haplotype was analyzed and their association with the incidence of prostate cancer was evaluated. Further, we detected AMACR expression in tumor with immunohistochemistry and analyzed its association with genotype regarding prostate cancer risk. Results. AG or GG genotype of rs2278008 (E277K) tended to lower prostate cancer risk. The minor G allele was found to be a significant allele that decreased the risk of prostate cancer (adjusted OR, 0.57; 95% CI, 0.35–0.93, P value = 0.025). In patients expression AMACR, AG or GG genotype was also significant genotype in terms of prostate cancer risk (adjusted OR, 0.47; 95% CI, 0.26–0.87, P value = 0.017). Further, [GGCGG] haplotype consisted of five coding SNPs of rs2278008, rs34677, rs2287939, rs10941112, and rs3195676 which decreased the risk of prostate cancer (P value = 0.047). Conclusions. Genetic variations of AMACR are associated with the risk of sporadic prostate cancer that underwent radical prostatectomy in Koreans.

Glyoxalase 1-419C>A variant is associated with oxidative stress: implications in prostate cancer progression

Glyoxalase 1 is a scavenging enzyme of potent precursors in reactive oxygen species formation and is involved in the occurrence and progression of human malignancies. Glyoxalase I A111E polymorphism has been suggested to influence its enzymatic activity. The present study was aimed at investigating the association of this polymorphism with oxidative stress and its implications in prostate cancer progression or survival. The polymorphism was genotyped in human differently aggressive and invasive prostate cancer cell lines, in 571 prostate cancer or 588 benign prostatic hyperplasia patients, and 580 healthy subjects by Polymerase Chain Reaction/Restriction Fragment Length Polymorphism. Glyoxalase 1 activity, the pro-oxidant Glyoxalase 1-related Argpyrimidine and oxidative stress biomarkers were evaluated by biochemical analyses. Glyoxalase 1 polymorphism was associated with an increase in Glyoxalase 1-related pro-oxidant Argpyrimidine and oxidative stress levels and cancer progression. The mutant A allele conferred a modest risk of prostate cancer, a marked risk of prostate cancer progression and a lower survival time, compared to the wild C allele. The results of our exploratory study point out a significant role for Glyoxalase 1 in prostate cancer progression, providing an additional candidate for risk assessment in prostate cancer patients and an independent prognostic factor for survival. Finally, we provided evidence of the biological plausibility of Glyoxalase 1 polymorphism, either alone or in combination with other ones, all related to oxidative stress control that represents a key event in PCa development and progression.

Genome-wide association studies on prostate cancer: the end or the beginning?

Prostate cancer (PCa) is the second most frequently diagnosed malignancy in men. Genome-wide association studies (GWAS) has been highly successful in discovering susceptibility loci for prostate cancer. Currently, more than twenty GWAS have identified more than fifty common variants associated with susceptibility with PCa. Yet with the increase in loci, voices from the scientific society are calling for more. In this review, we summarize current findings, discuss the common problems troubling current studies and shed light upon possible breakthroughs in the future. GWAS is the beginning of something wonderful. Although we are quite near the end of the beginning, post-GWAS studies are just taking off and future studies are needed extensively. It is believed that in the future GWAS information will be helpful to build a comprehensive system intergraded with PCa prevention, diagnosis, molecular classification, personalized therapy.

Personalized prostate specific antigen testing using genetic variants may reduce unnecessary prostate biopsies

PURPOSE

Recent studies have identified genetic variants associated with increased serum prostate specific antigen concentrations and prostate cancer risk, raising the possibility of diagnostic bias. By correcting for the effects of these variants on prostate specific antigen, it may be possible to create a personalized prostate specific antigen cutoff to more accurately identify individuals for whom biopsy is recommended. Therefore, we determined how many men would continue to meet common biopsy criteria after genetic correction of their measured prostate specific antigen concentrations.

MATERIALS AND METHODS

The genotypes of 4 single nucleotide polymorphisms previously associated with serum prostate specific antigen levels (rs2736098, rs10788160, rs11067228 and rs17632542) were determined in 964 healthy Caucasian volunteers without prostate cancer. Genetic correction of prostate specific antigen was performed by dividing an individual's prostate specific antigen value by his combined genetic risk. Analyses were used to compare the percentage of men who would meet commonly used biopsy thresholds (2.5 ng/ml or greater, or 4.0 ng/ml or greater) before and after genetic correction.

RESULTS

Genetic correction of serum prostate specific antigen results was associated with a significantly decreased percentage of men meeting biopsy thresholds. Genetic correction could lead to a 15% or 20% relative reduction in the total number of biopsies using a biopsy threshold of 2.5 ng/ml or greater, or 4.0 ng/ml or greater, respectively. In addition, genetic correction could result in an 18% to 22% reduction in the number of potentially unnecessary biopsies and a 3% decrease in potentially delayed diagnoses.

CONCLUSIONS

Our results suggest that 4 single nucleotide polymorphisms can be used to adjust a man's measured prostate specific antigen concentration and potentially delay or prevent unnecessary prostate biopsies in Caucasian men.

8q24 risk alleles in West African and Caribbean men

BACKGROUND

Multiple genetic studies have confirmed associations of 8q24 variants with susceptibility to prostate cancer (CaP). However, the magnitude of risk conferred in men living in West Africa is unknown.

METHODS

Here we determine the prevalence of 8q24 risk alleles and test for association with CaP risk alleles in West African (WA) descent populations from rural Nigeria, Cameroon, and the Caribbean island of Jamaica. Ten 8q24 SNPs were genotyped in histologically confirmed CaP cases (n = 308) and clinically evaluated controls (n = 469). In addition, unrelated individuals from Sierra Leone (n = 380) were genotyped for comparison of allele frequency comparisons.

RESULTS

SNPs rs6983561, rs7008482, and rs16901979 were significantly associated with CaP risk in WAs (P < 0.03). No associations with CaP were observed in our Caribbean samples. Risk alleles for rs6983267, rs7008482, and rs7000448 were highly prevalent (>84%) in West Africa. We also reveal that the A-risk allele for the 'African-specific' SNP bd11934905 was not observed in 1,886 chromosomes from three WA ethnic groups suggesting that this allele may not be common across West Africa, but is geographically restricted to specific ethnic group(s).

CONCLUSIONS

We provide evidence of association of 8q24 SNPs with prostate cancer risk in men from Nigeria and Cameroon. Our study is the first to reveal genetic risk due to 8q24 variants (in particular, region 2) with CaP within two WA countries. Most importantly, in light of the disparate burden of CaP in African-Americans, our findings support the need for larger genetic studies in WA descent populations to validate and discern function of susceptibility loci in the 8q24 region.

Identification of functionally active, low frequency copy number variants at 15q21.3 and 12q21.31 associated with prostate cancer risk

Copy number variants (CNVs) are a recently recognized class of human germ line polymorphisms and are associated with a variety of human diseases, including cancer. Because of the strong genetic influence on prostate cancer, we sought to identify functionally active CNVs associated with susceptibility of this cancer type. We queried low-frequency biallelic CNVs from 1,903 men of Caucasian origin enrolled in the Tyrol Prostate Specific Antigen Screening Cohort and discovered two CNVs strongly associated with prostate cancer risk. The first risk locus (P = 7.7 × 10(-4), odds ratio = 2.78) maps to 15q21.3 and overlaps a noncoding enhancer element that contains multiple activator protein 1 (AP-1) transcription factor binding sites. Chromosome conformation capture (Hi-C) data suggested direct cis-interactions with distant genes. The second risk locus (P = 2.6 × 10(-3), odds ratio = 4.8) maps to the α-1,3-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase C (MGAT4C) gene on 12q21.31. In vitro cell-line assays found this gene to significantly modulate cell proliferation and migration in both benign and cancer prostate cells. Furthermore, MGAT4C was significantly overexpressed in metastatic versus localized prostate cancer. These two risk associations were replicated in an independent PSA-screened cohort of 800 men (15q21.3, combined P = 0.006; 12q21.31, combined P = 0.026). These findings establish noncoding and coding germ line CNVs as significant risk factors for prostate cancer susceptibility and implicate their role in disease development and progression.

Biomarkers in prostate cancer epidemiology

Understanding the etiology of a disease such as prostate cancer may help in identifying populations at high risk, timely intervention of the disease, and proper treatment. Biomarkers, along with exposure history and clinical data, are useful tools to achieve these goals. Individual risk and population incidence of prostate cancer result from the intervention of genetic susceptibility and exposure. Biochemical, epigenetic, genetic, and imaging biomarkers are used to identify people at high risk for developing prostate cancer. In cancer epidemiology, epigenetic biomarkers offer advantages over other types of biomarkers because they are expressed against a person's genetic background and environmental exposure, and because abnormal events occur early in cancer development, which includes several epigenetic alterations in cancer cells. This article describes different biomarkers that have potential use in studying the epidemiology of prostate cancer. We also discuss the characteristics of an ideal biomarker for prostate cancer, and technologies utilized for biomarker assays. Among epigenetic biomarkers, most reports indicate GSTP1 hypermethylation as the diagnostic marker for prostate cancer; however, NKX2-5, CLSTN1, SPOCK2, SLC16A12, DPYS, and NSE1 also have been reported to be regulated by methylation mechanisms in prostate cancer. Current challenges in utilization of biomarkers in prostate cancer diagnosis and epidemiologic studies and potential solutions also are discussed.