Germline mutations in HOXB13 and prostate-cancer risk

Familial prostate cancer: the damage done and lessons learnt

BACKGROUND

A 51-year-old French Canadian man presented to his family physician owing to an extensive family history of prostate cancer in five brothers, his father and two paternal uncles. His serum PSA level was 4.9 ng/ml and a six-core biopsy revealed the presence of a prostate adenocarcinoma with a Gleason score of 7 (3+4). He was treated with radical prostatectomy. Repeat PSA tests revealed a gradual rise in PSA levels despite androgen deprivation therapy with bicalutamide and goserelin over the course of 3 years. Genetic evaluation was undertaken in view of his personal and family history. The proband died at the age of 58 years of widespread metastasis.

INVESTIGATIONS

PSA testing, six-core biopsy, genetic counselling and mutation analysis for French Canadian founder mutations in the BRCA1 and BRCA2 genes, histopathological review of tumour tissue from family members, examination of loss of heterozygosity at the BRCA2 gene locus, immunohistochemistry to determine the expression of the ERG nuclear oncoprotein in prostate tumours, genotyping with eight selected risk-associated single nucleotide polymorphisms, Doppler ultrasonography of the leg, CT of the abdomen and pelvis with intravenous and oral contrast, chest CT with intravenous contrast for the assessment of metastatic prostate cancer, genetic testing for the G84E variant in the HOXB13 gene.

DIAGNOSIS

Early-onset and aggressive prostate cancer associated with a nonsense French Canadian BRCA2 founder mutation, c.5857G>T (p.Glu1953(*)).

MANAGEMENT

Radical prostatectomy, hormone therapy with bicalutamide and goserelin, palliative chemotherapy initially with docetaxel plus prednisone then with mitoxantrone plus prednisone, as well as genetic counselling and testing for the proband and his family members.

HOXB13 G84E mutation in Finland: population-based analysis of prostate, breast, and colorectal cancer risk

BACKGROUND

A recently identified germline mutation G84E in HOXB13 was shown to increase the risk of prostate cancer. In a family-based analysis by The International Consortium for Prostate Cancer Genetics (ICPCG), the G84E mutation was most prevalent in families from the Nordic countries of Finland (22.4%) and Sweden (8.2%).

METHODS

To further investigate the importance of G84E in the Finns, we determined its frequency in more than 4,000 prostate cancer cases and 5,000 controls. In addition, 986 breast cancer and 442 colorectal cancer (CRC) cases were studied. Genotyping was conducted using TaqMan, MassARRAY iPLEX, and sequencing. Statistical analyses were conducted using Fisher exact test, and overall survival was analyzed using Cox modeling.

RESULTS

The frequency of the G84E mutation was significantly higher among patients with prostate cancer and highest among patients with a family history of the disease, hereditary prostate cancer [8.4% vs. 1.0% in controls; OR 8.8; 95% confidence interval (CI), 4.9-15.7]. The mutation contributed significantly to younger age (≤55 years) at onset and high prostate-specific antigen (PSA; ≥20 ng/mL) at diagnosis. An association with increased prostate cancer risk in patients with prior benign prostate hyperplasia (BPH) diagnosis was also revealed. No statistically significant evidence for a contribution in CRC risk was detected, but a suggestive role for the mutation was observed in familial BRCA1/2-negative breast cancer.

CONCLUSIONS

These findings confirm an increased cancer risk associated with the G84E mutation in the Finnish population, particularly for early-onset prostate cancer and cases with substantially elevated PSA.

IMPACT

This study confirms the overall importance of the HOXB13 G84E mutation in prostate cancer susceptibility.

β-catenin is required for prostate development and cooperates with Pten loss to drive invasive carcinoma

Prostate cancer is a major cause of male death in the Western world, but few frequent genetic alterations that drive prostate cancer initiation and progression have been identified. β-Catenin is essential for many developmental processes and has been implicated in tumorigenesis in many tissues, including prostate cancer. However, expression studies on human prostate cancer samples are unclear on the role this protein plays in this disease. We have used in vivo genetic studies in the embryo and adult to extend our understanding of the role of β-Catenin in the normal and neoplastic prostate. Our gene deletion analysis revealed that prostate epithelial β-Catenin is required for embryonic prostate growth and branching but is dispensable in the normal adult organ. During development, β-Catenin controls the number of progenitors in the epithelial buds and regulates a discrete network of genes, including c-Myc and Nkx3.1. Deletion of β-Catenin in a Pten deleted model of castration-resistant prostate cancer demonstrated it is dispensable for disease progression in this setting. Complementary overexpression experiments, through in vivo protein stabilization, showed that β-Catenin promotes the formation of squamous epithelia during prostate development, even in the absence of androgens. β-Catenin overexpression in combination with Pten loss was able to drive progression to invasive carcinoma together with squamous metaplasia. These studies demonstrate that β-Catenin is essential for prostate development and that an inherent property of high levels of this protein in prostate epithelia is to drive squamous fate differentiation. In addition, they show that β-Catenin overexpression can promote invasive prostate cancer in a clinically relevant model of this disease. These data provide novel information on cancer progression pathways that give rise to lethal prostate disease in humans.

Prostate cancer is a major cause of male death in the Western world, but few genes involved in this disease have been identified. We have undertaken an in-depth in vivo analysis in the prostate of the β-Catenin protein, which has been shown to be important in many processes during embryogenesis and has been implicated in tumorigenesis. Our studies demonstrate that β-Catenin is essential for prostate development but is dispensable in the normal adult organ. Analysis of a mouse model of a frequently mutated human prostate tumour suppressor, Pten loss, revealed that β-Catenin is not required for neoplastic formation in this model, even in castrated conditions. However, increased β-Catenin levels can cooperate with Pten loss to promote the progression of aggressive invasive prostate cancer together with squamous metaplasia. These data uncover the role of β-Catenin in the prostate and provide new insights on how pathways interact to drive human prostate cancer.

A novel germline mutation in HOXB13 is associated with prostate cancer risk in Chinese men

BACKGROUND

A rare mutation G84E in HOXB13 was recently identified to be associated with prostate cancer (PCa) in Caucasians. The goal of this study is to test association between HOXB13 genetic variants and PCa risk in Chinese men.

METHODS

All study subjects were part of the Chinese Consortium for Prostate Cancer Genetics (ChinaPCa). In the first stage, we screened for mutations by sequencing the HOXB13 coding region in 96 unrelated PCa patients. In stage 2, G84E and novel mutations found in stage 1 were genotyped in 671 PCa patients and 1,536 controls. In stage 3, mutation status in 751 additional PCa patients was imputed via haplotype.

RESULTS

The G84E mutation was not detected in this study. However, a novel mutation, G135E, was identified among 96 patients in stage 1. It was also observed twice in 575 additional PCa patients but not in 1,536 control subjects of stage 2. The frequency of G135E was significantly different between cases and controls, with a P-value of 0.027, based on Fisher's exact test. Haplotype estimation showed that G135E mutation carriers shared a unique haplotype that was not observed in other subjects. In stage 3, two more PCa patients were predicted to carry the G135E mutation.

CONCLUSIONS

We identified a novel rare mutation in the HOXB13 gene, G135E, which appears to be a founder mutation. This mutation is associated with increased PCa risk in Chinese men. Consistent with a previous report, our findings provide further evidence that rare mutations in HOXB13 contribute to PCa risk.

HOXB13 is a susceptibility gene for prostate cancer: results from the International Consortium for Prostate Cancer Genetics (ICPCG)

Prostate cancer has a strong familial component but uncovering the molecular basis for inherited susceptibility for this disease has been challenging. Recently, a rare, recurrent mutation (G84E) in HOXB13 was reported to be associated with prostate cancer risk. Confirmation and characterization of this finding is necessary to potentially translate this information to the clinic. To examine this finding in a large international sample of prostate cancer families, we genotyped this mutation and 14 other SNPs in or flanking HOXB13 in 2,443 prostate cancer families recruited by the International Consortium for Prostate Cancer Genetics (ICPCG). At least one mutation carrier was found in 112 prostate cancer families (4.6 %), all of European descent. Within carrier families, the G84E mutation was more common in men with a diagnosis of prostate cancer (194 of 382, 51 %) than those without (42 of 137, 30 %), P = 9.9 × 10(-8) [odds ratio 4.42 (95 % confidence interval 2.56-7.64)]. A family-based association test found G84E to be significantly over-transmitted from parents to affected offspring (P = 6.5 × 10(-6)). Analysis of markers flanking the G84E mutation indicates that it resides in the same haplotype in 95 % of carriers, consistent with a founder effect. Clinical characteristics of cancers in mutation carriers included features of high-risk disease. These findings demonstrate that the HOXB13 G84E mutation is present in ~5 % of prostate cancer families, predominantly of European descent, and confirm its association with prostate cancer risk. While future studies are needed to more fully define the clinical utility of this observation, this allele and others like it could form the basis for early, targeted screening of men at elevated risk for this common, clinically heterogeneous cancer.

Risk stratification in prostate cancer screening

Screening for prostate cancer is a controversial topic within the field of urology. The US Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial did not demonstrate any difference in prostate-cancer-related mortality rates between men screened annually rather than on an 'opportunistic' basis. However, in the world's largest trial to date--the European Randomised Study of Screening for Prostate Cancer--screening every 2-4 years was associated with a 21% reduction in prostate-cancer-related mortality rate after 11 years. Citing the uncertain ratio between potential harm and potential benefit, the US Preventive Services Task Force recently recommended against serum PSA screening. Although this ratio has yet to be elucidated, PSA testing--and early tumour detection--is undoubtedly beneficial for some individuals. Instead of adopting a 'one size fits all' approach, physicians are likely to perform personalized risk assessment to minimize the risk of negative consequences, such as anxiety, unnecessary testing and biopsies, overdiagnosis, and overtreatment. The PSA test needs to be combined with other predictive factors or be used in a more thoughtful way to identify men at risk of symptomatic or life-threatening cancer, without overdiagnosing indolent disease. A risk-adapted approach is needed, whereby PSA testing is tailored to individual risk.

An inherited NBN mutation is associated with poor prognosis prostate cancer

BACKGROUND

To establish the contribution of eight founder alleles in three DNA damage repair genes (BRCA1, CHEK2 and NBS1) to prostate cancer in Poland, and to measure the impact of these variants on survival among patients.

METHODS

Three thousand seven hundred fifty men with prostate cancer and 3956 cancer-free controls were genotyped for three founder alleles in BRCA1 (5382insC, 4153delA, C61G), four alleles in CHEK2 (1100delC, IVS2+1G>A, del5395, I157T), and one allele in NBS1 (657del5).

RESULTS

The NBS1 mutation was detected in 53 of 3750 unselected cases compared with 23 of 3956 (0.6%) controls (odds ratio (OR)=2.5; P=0.0003). A CHEK2 mutation was seen in 383 (10.2%) unselected cases and in 228 (5.8%) controls (OR=1.9; P<0.0001). Mutation of BRCA1 (three mutations combined) was not associated with the risk of prostate cancer (OR=0.9; P=0.8). In a subgroup analysis, the 4153delA mutation was associated with early-onset (age ≤ 60 years) prostate cancer (OR=20.3, P=0.004). The mean follow-up was 54 months. Mortality was significantly worse for carriers of a NBS1 mutation than for non-carriers (HR=1.85; P=0.008). The 5-year survival for men with an NBS1 mutation was 49%, compared with 72% for mutation-negative cases.

CONCLUSION

A mutation in NBS1 predisposes to aggressive prostate cancer. These data are relevant to the prospect of adapting personalised medicine to prostate cancer prevention and treatment.

A study based on whole-genome sequencing yields a rare variant at 8q24 associated with prostate cancer

In Western countries, prostate cancer is the most prevalent cancer of men and one of the leading causes of cancer-related death in men. Several genome-wide association studies have yielded numerous common variants conferring risk of prostate cancer. Here, we analyzed 32.5 million variants discovered by whole-genome sequencing 1,795 Icelanders. We identified a new low-frequency variant at 8q24 associated with prostate cancer in European populations, rs188140481[A] (odds ratio (OR) = 2.90; P(combined) = 6.2 × 10(-34)), with an average risk allele frequency in controls of 0.54%. This variant is only very weakly correlated (r(2) ≤ 0.06) with previously reported risk variants at 8q24, and its association remains significant after adjustment for all known risk-associated variants. Carriers of rs188140481[A] were diagnosed with prostate cancer 1.26 years younger than non-carriers (P = 0.0059). We also report results for a previously described HOXB13 variant (rs138213197[T]), confirming it as a prostate cancer risk variant in populations from across Europe.

The HOXB13 p.Gly84Glu mutation is not associated with the risk of breast cancer

Recently, the HOXB13 gene has been shown to be a susceptibility gene for prostate cancer. HOXB13 is overexpressed in breast cancer tissues and HOXB13 expression in combination with low expression of IL17BR is predictive for a tamoxifen response in ER-positive breast cancers. Based on observations, we hypothesized that the HOXB13 p.Gly84Glu mutation might be associated with breast cancer risk. We genotyped this mutation in the germline DNA of 4,037 women with breast cancer (including 1,082 familial cases) and in 2,762 controls from Canada and Poland. Seven heterozygous carriers of the HOXB13 p.Gly84Glu mutation were found in the cases (0.17 %) compared to four carriers among the controls (0.14 %; OR = 1.2, 95 % CI = 0.34–4.1, p = 1.0). Only one of the seven carriers had a family history of breast cancer. This study does not support the hypothesis that women who carry the HOXB13 Gly84Glu mutation are at increased risk of breast cancer.

Androgens, diabetes and prostate cancer

Metabolic disorders such as diabetes, obesity and the metabolic syndrome have been shown to modulate prostate cancer (PCa) risk and aggressiveness in population-based and experimental studies. While associations between these conditions are modest and complex, two consistent findings have emerged. First, there is observational evidence that obesity and associated insulin excess are linked to increased PCa aggressiveness and worse outcomes. Secondly and somewhat paradoxically, long-standing diabetes may be protective against PCa development. This apparent paradox may be due to the fact that long-standing diabetes is associated with insulin depletion and decreased IGF1 signalling. Men with obesity or diabetes have moderate reductions in their androgen levels. The interconnectedness of metabolic and androgen status complicates the dissection of the individual roles of these factors in PCa development and progression. Metabolic factors and androgens may promote prostate carcinogenesis via multiple mechanisms including inflammation, adipokine action, fatty acid metabolism and IGF signalling. Moreover, androgen deprivation, given to men with PCa, has adverse metabolic consequences that need to be taken into account when estimating the risk benefit ratio of this therapy. In this review, we will discuss the current epidemiological and mechanistic evidence regarding the interactions between metabolic conditions, sex steroids and PCa risk and management.

Beyond PSA: the next generation of prostate cancer biomarkers

Since the introduction of serum prostate-specific antigen (PSA) screening 25 years ago, prostate cancer diagnosis and management have been guided by this biomarker. Yet, PSA has proven controversial as a screening assay owing to several inherent limitations. The next wave of prostate cancer biomarkers has emerged, introducing new assays in serum and urine that may supplement or, in time, replace PSA because of their higher cancer specificity. This expanding universe of biomarkers has been facilitated, in large part, by new genomic technologies that have enabled an unbiased look at cancer biology. Such efforts have produced several notable success stories that involve rapidly moving biomarkers from the bench to the clinic. However, biomarker research has centered on disease diagnostics, rather than prognosis and prediction, which would address disease management. The development of biomarkers to stratify risk of prostate cancer aggressiveness at the time of screening remains the greatest unmet clinical need in prostate cancer. We review the current state of prostate cancer biomarker research, including the PSA revolution, its impact on early cancer detection, the recent advances in biomarker discovery, and the future efforts that promise to improve clinical management of this disease.

Prostate cancer: germline prediction for a commonly variable malignancy

What's known on the subject? and What does the study add? Prostate cancer is a heterogeneous disease and biomarkers to predict its incidence and subsequent clinical behaviour are needed to tailor screening, prevention and therapeutic strategies. Rare mutations in genes such as BRCA1, BRCA2 and HOXB13 can affect prostate cancer incidence and/or clinical behaviour. Genome wide association studies (GWAS) have identified more common genetic variations that explain an estimated 20% of familial prostate cancer risk. In this review, we focus on the potential of germline genetic variation to provide biomarkers for prostate cancer screening, prevention and management. We discuss how germline genetics may have a role in treatment selection if reliable pharmacogenetic predictors of efficacy and toxicity can be identified. We have outlined possible mechanisms for including germline investigation in future prostate cancer clinical trials.

OBJECTIVES

• Prostate cancer is a heterogeneous disease and biomarkers to predict its incidence and subsequent clinical behaviour are needed to tailor screening, prevention and therapeutic strategies. • In this review we focus on the potential of germline genetic variation to provide these biomarkers.

METHODS

• We review the published literature on germline genetics in prostate cancer and examine the possibility of including germline genetic biomarkers in future prostate cancer clinical trials.

RESULTS

• Rare mutations in genes such as BRCA1, BRCA2 and HOXB13 can affect prostate cancer incidence and/or clinical behaviour. • Genome-wide association studies (GWAS) have identified more common genetic variations that explain an estimated 20% of familial prostate cancer risk. • Germline genetics may have a role in treatment selection, if reliable pharmacogenetic predictors of efficacy and toxicity can be identified.

CONCLUSION

• This rapidly emerging area of prostate cancer research may provide answers to current clinical conundrums in the prostate cancer treatment paradigm. We have outlined possible mechanisms for including germline investigation in future prostate cancer clinical trial design.

Genetic heterogeneity in Finnish hereditary prostate cancer using ordered subset analysis

Prostate cancer (PrCa) is the most common male cancer in developed countries and the second most common cause of cancer death after lung cancer. We recently reported a genome-wide linkage scan in 69 Finnish hereditary PrCa (HPC) families, which replicated the HPC9 locus on 17q21-q22 and identified a locus on 2q37. The aim of this study was to identify and to detect other loci linked to HPC. Here we used ordered subset analysis (OSA), conditioned on nonparametric linkage to these loci to detect other loci linked to HPC in subsets of families, but not the overall sample. We analyzed the families based on their evidence for linkage to chromosome 2, chromosome 17 and a maximum score using the strongest evidence of linkage from either of the two loci. Significant linkage to a 5-cM linkage interval with a peak OSA nonparametric allele-sharing LOD score of 4.876 on Xq26.3-q27 (ΔLOD=3.193, empirical P=0.009) was observed in a subset of 41 families weakly linked to 2q37, overlapping the HPCX1 locus. Two peaks that were novel to the analysis combining linkage evidence from both primary loci were identified; 18q12.1-q12.2 (OSA LOD=2.541, ΔLOD=1.651, P=0.03) and 22q11.1-q11.21 (OSA LOD=2.395, ΔLOD=2.36, P=0.006), which is close to HPC6. Using OSA allows us to find additional loci linked to HPC in subsets of families, and underlines the complex genetic heterogeneity of HPC even in highly aggregated families.

The tip of the iceberg: a countercurrents series

In February 2012, Ambry Genetics, a testing company based in Aliso Viejo, California, began to offer the BreastNext genetic test to women with earlyonset or familial breast cancer [...]

Deregulation of a Hox protein regulatory network spanning prostate cancer initiation and progression

PURPOSE

The aberrant activity of developmental pathways in prostate cancer may provide significant insight into predicting tumor initiation and progression, as well as identifying novel therapeutic targets. To this end, despite shared androgen-dependence and functional similarities to the prostate gland, seminal vesicle cancer is exceptionally rare.

EXPERIMENTAL DESIGN

We conducted genomic pathway analyses comparing patient-matched normal prostate and seminal vesicle epithelial cells to identify novel pathways for tumor initiation and progression. Derived gene expression profiles were grouped into cancer biomodules using a protein-protein network algorithm to analyze their relationship to known oncogenes. Each resultant biomodule was assayed for its prognostic ability against publically available prostate cancer patient gene array datasets.

RESULTS

Analyses show that the embryonic developmental biomodule containing four homeobox gene family members (Meis1, Meis2, Pbx1, and HoxA9) detects a survival difference in a set of watchful-waiting patients (n = 172, P = 0.05), identify men who are more likely to recur biochemically postprostatectomy (n = 78, P = 0.02), correlate with Gleason score (r = 0.98, P = 0.02), and distinguish between normal prostate, primary tumor, and metastatic disease. In contrast to other cancer types, Meis1, Meis2, and Pbx1 expression is decreased in poor-prognosis tumors, implying that they function as tumor suppressor genes for prostate cancer. Immunohistochemical staining documents nuclear basal-epithelial and stromal Meis2 staining, with loss of Meis2 expression in prostate tumors.

CONCLUSION

These data implicate deregulation of the Hox protein cofactors Meis1, Meis2, and Pbx1 as serving a critical function to suppress prostate cancer initiation and progression.

Emerging putative biomarkers: the role of alpha 2 and 6 integrins in susceptibility, treatment, and prognosis

The genetic architecture underpinning prostate cancer is complex, polygenic and despite recent significant advances many questions remain. Advances in genetic technologies have greatly improved our ability to identify genetic variants associated with complex disease including prostate cancer. Genome-wide association studies (GWASs) and microarray gene expression studies have identified genetic associations with prostate cancer susceptibility and tumour development. The integrins feature prominently in both studies examining the underlying genetic susceptibility and mechanisms driving prostate tumour development. Integrins are cell adhesion molecules involved in extracellular and intracellular signalling and are imperative for tumour development, migration, and angiogenesis. Although several integrins have been implicated in tumour development, the roles of integrin α(2) and integrin α(6) are the focus of this paper as evidence is now emerging that these integrins are implicit in prostate cancer susceptibility, cancer stem cell biology, angiogenesis, cell migration, and metastases to bone and represent potential biomarkers and therapeutic targets. There currently exists an urgent need to develop tools that differentiate indolent from aggressive prostate cancers and predict how patients will respond to treatment. This paper outlines the evidence supporting the use of α(2) and α(6) integrins in clinical applications for tailored patient treatment.

A population-based assessment of germline HOXB13 G84E mutation and prostate cancer risk

BACKGROUND

A rare but recurrent missense mutation (G84E, rs138213197) in the gene homeobox B13 (HOXB13) was recently reported to be associated with hereditary prostate cancer.

OBJECTIVE

To explore the prevalence and penetrance of HOXB13 G84E in a general population.

DESIGN, SETTING, AND PARTICIPANTS

G84E and 14 additional HOXB13 polymorphisms were genotyped in two population-based, Swedish, case-control samples (Cancer of the Prostate in Sweden [CAPS] and Stockholm-1) comprising 4693 controls and 5003 prostate cancer cases. CAPS collected data on patients and population controls nationally between 2001 and 2003. Stockholm-1 collected data on biopsy-positive patients and biopsy-negative controls in the Stockholm area between 2005 and 2007.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The outcome was pathologically verified prostate cancer. Relative and absolute risks among HOXB13 G84E mutation carriers were explored, as was the combined impact on disease risk of G84E and a polygenic score based on 33 established, common, low-risk variants.

RESULTS AND LIMITATIONS

HOXB13 G84E was observed in 1.3% of population controls and was strongly associated with prostate cancer risk (CAPS: odds ratio [OR]: 3.4; 95% confidence interval [CI], 2.2-5.4; Stockholm-1: OR: 3.5; 95% CI, 2.4-5.2). The strongest association was observed for young-onset (OR: 8.6; 95% CI, 5.1-14.0) and hereditary (OR: 6.6; 95% CI, 3.3-12.0) prostate cancer. Haplotype analyses supported that G84E is a founder mutation. G84E carriers have an estimated 33% (95% CI, 23-46) cumulative risk to age 80 yr of prostate cancer, compared to 12% (95% CI, 11-13) among noncarriers. For G84E carriers within the top quartile of a polygenic score of established susceptibility variants, the cumulative risk was estimated at 48% (95% CI, 36-64).

CONCLUSIONS

HOXB13 G84E is prevalent in >1% of the Swedish population and is associated with a 3.5-fold increased risk of prostate cancer. One-third of G84E carriers will be diagnosed with prostate cancer, which has implications for surveillance in mutation carriers.

Confirmation of the HOXB13 G84E germline mutation in familial prostate cancer

BACKGROUND

A recent study of familial and early onset prostate cancer reported a recurrent rare germline mutation of HOXB13 among men of European descent. The gene resides within the 17q21 hereditary prostate cancer linkage interval.

METHODS

We evaluated the G84E germline mutation (rs138213197) of HOXB13 in a case-control study of familial prostate cancer at Vanderbilt University (Nashville, TN) to independently evaluate the association of the mutation with familial prostate cancer. We genotyped 928 familial prostate cancer probands and 930 control probands without a personal or family history of prostate cancer.

RESULTS

Our study confirmed the association between the G84E mutation of HOXB13 and risk of prostate cancer among subjects of European descent. We observed the mutation in 16 familial cases and in two controls, each as heterozygotes. The odds ratio (OR) for prostate cancer was 7.9 [95% confidence interval, (CI) 1.8-34.5, P = 0.0062] among carriers of the mutation. The carrier rate was 1.9% among all familial case probands and 2.7% among probands of pedigrees with ≥3 affected. In a separate case series of 268 probands of European descent with no additional family history of prostate cancer, the carrier rate was 1.5%.

CONCLUSIONS

The germline mutation G84E of HOXB13 is a rare but recurrent mutation associated with elevated risk of prostate cancer in men of European descent, with an effect size that is greater than observed for previously validated risk variants of genome wide association studies.

IMPACT

This study independently confirms the association of a germline HOXB13 mutation with familial prostate cancer.

The role of genetic markers in the management of prostate cancer

CONTEXT

Despite widespread screening for prostate cancer (PCa) and major advances in the treatment of metastatic disease, PCa remains the second most common cause of cancer death for men in the Western world. In addition, the use of prostate-specific antigen testing has led to the diagnosis of many potentially indolent cancers, and aggressive treatment of these cancers has caused significant morbidity without clinical benefit in many cases. The recent discoveries of inherited and acquired genetic markers associated with PCa initiation and progression provide an opportunity to apply these findings to guide clinical decision making.

OBJECTIVE

In this review, we discuss the potential use of genetic markers to better define groups of men at high risk of developing PCa, to improve screening techniques, to discriminate indolent versus aggressive disease, and to improve therapeutic strategies in patients with advanced disease.

EVIDENCE ACQUISITION

PubMed-based literature searches and abstracts through January 2012 provided the basis for this literature review. We also examined secondary sources from reference lists of retrieved articles and data presented at recent congresses. Cited review articles are only from the years 2007-2012, favoring more recent discussions because of the rapidly changing field. Original research articles were curated based on favoring large sample sizes, independent validation, frequent citations, and basic science directly related to potentially clinically relevant prognostic or predictive markers. In addition, all authors on the manuscript evaluated and interpreted the data acquired.

EVIDENCE SYNTHESIS

We address the use of inherited genetic variants to assess risk of PCa development, risk of advanced disease, and duration of response to hormonal therapies. The potential for using urine measurements such as prostate cancer antigen 3 (PCA3) RNA and the transmembrane protease, serine 2 v-ets erythroblastosis virus E26 oncogene homolog (avian) (TMPRSS2-ERG) gene fusion to aid screening is discussed. Multiple groups have developed gene expression signatures from primary prostate tumors correlating with poor prognosis, and attempts to improve and standardize these signatures as diagnostic tests are presented. Massive sequencing efforts are underway to define important somatic genetic alterations (amplifications, deletions, point mutations, translocations) in PCa, and these alterations hold great promise as prognostic markers and for predicting response to therapy. We provide a rationale for assessing genetic markers in metastatic disease for guiding choice of therapy and for stratifying patients in clinical trials, and discuss challenges in clinical trial design incorporating the use of these markers.

CONCLUSIONS

The use of genetic markers has the potential to aid disease screening, improve prognostic discrimination, and prediction of response to treatment. However, most markers have not been prospectively validated for providing useful prognostic or predictive information or improvement upon clinicopathologic parameters already in use. Significant efforts are underway to develop these research findings into clinically useful diagnostic tests in order to improve clinical decision making.

Inherited susceptibility for aggressive prostate cancer

Whether or not there is inherited basis for prostate cancer aggressiveness is not clear, but advances in DNA analysis should provide an answer to this question in the very near future.