BACKGROUND Family history is a significant risk factor for prostate cancer, although the molecular basis for this association is poorly understood. Linkage studies have implicated chromosome 17q21-22 as a possible location of a prostate-cancer susceptibility gene. METHODS We screened more than 200 genes in the 17q21-22 region by sequencing germline DNA from 94 unrelated patients with prostate cancer from families selected for linkage to the candidate region. We tested family members, additional case subjects, and control subjects to characterize the frequency of the identified mutations. RESULTS Probands from four families were discovered to have a rare but recurrent mutation (G84E) in HOXB13 (rs138213197), a homeobox transcription factor gene that is important in prostate development. All 18 men with prostate cancer and available DNA in these four families carried the mutation. The carrier rate of the G84E mutation was increased by a factor of approximately 20 in 5083 unrelated subjects of European descent who had prostate cancer, with the mutation found in 72 subjects (1.4%), as compared with 1 in 1401 control subjects (0.1%) (P = 8.5×10−7). The mutation was significantly more common in men with early-onset, familial prostate cancer (3.1%) than in those with late-onset, nonfamilial prostate cancer (0.6%) (P = 2.0×10−6). CONCLUSIONS The novel HOXB13 G84E variant is associated with a significantly increased risk of hereditary prostate cancer. Although the variant accounts for a small fraction of all prostate cancers, this finding has implications for prostate-cancer risk assessment and may provide new mechanistic insights into this common cancer. (Funded by the National Institutes of Health and others.)

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Although prostate cancer is the most common non-cutaneous malignancy diagnosed in men in the United States, little is known about inherited factors that influence its genetic predisposition. Here we report that germline mutations in the gene encoding 2'-5'-oligoadenylate(2-5A)-dependent RNase L (RNASEL) segregate in prostate cancer families that show linkage to the HPC1 (hereditary prostate cancer 1) region at 1q24-25 (ref. 9). We identified RNASEL by a positional cloning/candidate gene method, and show that a nonsense mutation and a mutation in an initiation codon of RNASEL segregate independently in two HPC1-linked families. Inactive RNASEL alleles are present at a low frequency in the general population. RNASEL regulates cell proliferation and apoptosis through the interferon-regulated 2-5A pathway and has been suggested to be a candidate tumor suppressor gene. We found that microdissected tumors with a germline mutation showed loss of heterozygosity and loss of RNase L protein, and that RNASEL activity was reduced in lymphoblasts from heterozyogous individuals compared with family members who were homozygous with respect to the wildtype allele. Thus, germline mutations in RNASEL may be of diagnostic value, and the 2-5A pathway might provide opportunities for developing therapies for those with prostate cancer.

Recent advances in understanding the molecular genetics of common adult tumors have indicated that multiple genetic alterations including the activation of oncogenes and the inactivation of tumor suppressor genes are important in the pathogenesis of these tumors. Loss of heterozygosity is a hallmark of tumor suppressor gene inactivation and has been used to identify chromosomal regions that contain these genes. We have examined allelic loss in the most common tumor in men, prostate cancer. Twenty-eight prostate cancer specimens have been examined for loss of heterozygosity at 11 different chromosomal arms including 3p, 7q, 9q, lOp, lOq, Ulp, 13q, 16p, 16q, 17p, and 18q. Fifty-four percent'(13/24) of clinically localized tumors and 4 of 4 metastatic tumors showed loss of heterozygosity on at least one chromosome. Chromosomes 16q and lOq exhibited the highest frequency of loss of heterozygosity with 30% of tumors showing loss at these chromosomes. These data demonstrate that allelic loss is a common event in prostate cancer and suggest that chromosomes 16q and lOq may contain the sites of tumor suppressor genes important in the pathogenesis of human prostate cancer.

Deletions on human chromosome 8p22-23 in prostate cancer cells and linkage studies in families affected with hereditary prostate cancer (HPC) have implicated this region in the development of prostate cancer. The macrophage scavenger receptor 1 gene (MSR1, also known as SR-A) is located at 8p22 and functions in several processes proposed to be relevant to prostate carcinogenesis. Here we report the results of genetic analyses that indicate that mutations in MSR1 may be associated with risk of prostate cancer. Among families affected with HPC, we identified six rare missense mutations and one nonsense mutation in MSR1. A family-based linkage and association test indicated that these mutations co-segregate with prostate cancer (P = 0.0007). In addition, among men of European descent, MSR1 mutations were detected in 4.4% of individuals affected with non-HPC as compared with 0.8% of unaffected men (P = 0.009). Among African American men, these values were 12.5% and 1.8%, respectively (P = 0.01). These results show that MSR1 may be important in susceptibility to prostate cancer in men of both African American and European descent.

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Understanding the molecular etiology of prostate cancer (CaP) progression is paramount for broadening current diagnostic and therapeutic modalities. Current interest in the role of wnt pathway signaling in prostate tumorigenesis was generated with the ®nding of b-catenin mutation and corresponding nuclear localization in primary lesions. The recent ®nding of b-catenin-induced enhancement of androgen receptor (AR) function potentially ties b-catenin to key regulatory steps of prostate cell growth, di erentiation, and transformation. By immunohistological analysis of metastatic tumors, we detected nuclear bcatenin in 20% of lethal CaP cases, suggesting a more common role for b-catenin in advanced disease than would be predicted by its mutation rate. Interestingly, bcatenin nuclear localization was found to occur concomitantly with androgen-induced regrowth of normal rat prostate. These in vivo observations likely implicate b-catenin involvement in both normal and neoplastic prostate physiology, thus prompting our interest in further characterizing modes of b-catenin signaling in prostate cells. Extending our previous ®ndings, we demonstrate that transient b-catenin over-expression stimulates T cell factor (TCF) signaling in most CaP cell lines. Further, this activity is not subject to crossregulation by phosphoinositide-3-kinase (PI3-K)/Akt signaling, a stimulatory pathway often upregulated in CaP upon PTEN inactivation. Consistent with a previous report, we observed that transient b-catenin overexpression enhances AR-mediated transcription o two natural target gene promoters. However, we were unable to recapitulate b-catenin-induced stimulation of ectopically expressed AR in AR-negative cells, suggesting that other AR-associated factors are required for this activity. Although LNCaP cells are capable of this mode of AR co-stimulation, stable expression of mutant b-catenin did not alter their proliferative response to androgen. In total, our characterization of b-catenin signaling in CaP reveals the complex nature of its activity in prostate tissue, indicating that b-catenin potentially contributes to multiple stimulatory inputs required for disease progression.

Background Germline mutations in BRCA1/2 and ATM have been associated with prostate cancer (PCa) risk. Objective To directly assess whether germline mutations in these three genes distinguish lethal from indolent PCa and whether they confer any effect on age at death. Design, setting, and participants A retrospective case-case study of 313 patients who died of PCa and 486 patients with low-risk localized PCa of European, African, and Chinese descent. Germline DNA of each of the 799 patients was sequenced for these three genes. Outcome measurements and statistical analysis Mutation carrier rates and their effect on lethal PCa were analyzed using the Fisher’s exact test and Cox regression analysis, respectively. Results and limitations The combined BRCA1/2 and ATM mutation carrier rate was significantly higher in lethal PCa patients (6.07%) than localized PCa patients (1.44%), p = 0.0007. The rate also differed significantly among lethal PCa patients as a function of age at death (10.00%, 9.08%, 8.33%, 4.94%, and 2.97% in patients who died ≤60 yr, 61–65 yr, 66–70 yr, 71–75 yr, and over 75 yr, respectively, p = 0.046) and time to death after diagnosis (12.26%, 4.76%, and 0.98% in patients who died ≤5 yr, 6–10 yr, and > 10 yr after a PCa diagnosis, respectively, p = 0.0006). Survival analysis in the entire cohort revealed mutation carriers remained an independent predictor of lethal PCa after adjusting for race and age, prostate-specific antigen, and Gleason score at the time of diagnosis (hazard ratio = 2.13, 95% confidence interval: 1.24–3.66, p = 0.004). A limitation of this study is that other DNA repair genes were not analyzed. Conclusions Mutation status of BRCA1/2 and ATM distinguishes risk for lethal and indolent PCa and is associated with earlier age at death and shorter survival time. Patient summary Prostate cancer patients with inherited mutations in BRCA1/2 and ATM are more likely to die of prostate cancer and do so at an earlier age.