Confirmation of prostate cancer susceptibility genes using high-risk families

Canine Cancer Genomics: Lessons for Canine and Human Health

Dogs are second only to humans in medical surveillance and preventative health care, leading to a recent perception of increased cancer incidence. Scientific priorities in veterinary oncology have thus shifted, with a demand for cancer genetic screens, better diagnostics, and more effective therapies. Most dog breeds came into existence within the last 300 years, and many are derived from small numbers of founders. Each has undergone strong artificial selection, in which dog fanciers selected for many traits, including body size, fur type, color, skull shape, and behavior, to create novel breeds. The adoption of the breed barrier rule-no dog may become a registered member of a breed unless both its dam and its sire are registered members-ensures a relatively closed genetic pool within each breed. As a result, there is strong phenotypic homogeneity within breeds but extraordinary phenotypic variation between breeds. One consequence of this is the high level of breed-associated genetic disease. We and others have taken advantage of this to identify genes for a large number of canine maladies for which mouse models do not exist, particularly with regard to cancer.

Admixture Mapping Links RACGAP1 Regulation to Prostate Cancer in African Americans

BACKGROUND/AIM

Prostate cancer is the most common malignancy in US males. African American men have higher incidence and mortality rates than European Americans. Five single nucleotide polymorphisms are associated with PCa. We hypothesized haplotypes inferred from these SNPs are also associated with PCa.

PATIENTS AND METHODS

We genotyped SNPs in a case-control admixture mapping study. SNP haplotypes inferred for 157 PCa cases and 150 controls were used in the regression analysis.

RESULTS

We found an association between "GTCCC", "ATTCT", and "ACCCC" haplotypes and PCa after ancestry adjustment (OR=3.62, 95%CI=1.42-9.21, p=0.0070; OR=7.89, 95%CI=2.36-26.31, p=0.0008; OR=4.34, 95%CI=1.75-10.78, p=0.0016). The rs615382 variant disrupts the recombination signal binding protein with immunoglobulin kappa J binding site in Rac GTPase activating protein 1 (RACGAP1).

CONCLUSION

Disruption of notch 1 mediated-repression of RACGAP1 may contribute to PCa in African Americans.

A personal journey of discovery: developing technology and changing biology

This autobiographical article describes my experiences in developing chemically based, biological technologies for deciphering biological information: DNA, RNA, proteins, interactions, and networks. The instruments developed include protein and DNA sequencers and synthesizers, as well as ink-jet technology for synthesizing DNA chips. Diverse new strategies for doing biology also arose from novel applications of these instruments. The functioning of these instruments can be integrated to generate powerful new approaches to cloning and characterizing genes from a small amount of protein sequence or to using gene sequences to synthesize peptide fragments so as to characterize various properties of the proteins. I also discuss the five paradigm changes in which I have participated: the development and integration of biological instrumentation; the human genome project; cross-disciplinary biology; systems biology; and predictive, personalized, preventive, and participatory (P4) medicine. Finally, I discuss the origins, the philosophy, some accomplishments, and the future trajectories of the Institute for Systems Biology.

Genomic scan of 254 hereditary prostate cancer families

Hereditary prostate cancer (HPC) is a genetically heterogeneous disease, complicating efforts to map and clone susceptibility loci. We have used stratification of a large dataset of 254 HPC families in an effort to improve power to detect HPC loci and to understand what types of family features may improve locus identification. The strongest result is that of a dominant locus at 6p22.3 (heterogeneity LOD (HLOD) = 2.51), the evidence for which is increased by consideration of the age of PC onset (HLOD = 3.43 in 214 families with median age-of-onset 56-72 years) and co-occurrence of primary brain cancer (HLOD = 2.34 in 21 families) in the families. Additional regions for which we observe modest evidence for linkage include chromosome 7q and 17p. Only weak evidence of several previously implicated HPC regions is detected. These analyses support the existence of multiple HPC loci, whose presence may be best identified by analyses of large, including pooled, datasets which consider locus heterogeneity.

Oligogenic segregation analysis of hereditary prostate cancer pedigrees: evidence for multiple loci affecting age at onset

Previous studies have suggested strong evidence for a hereditary component to prostate cancer (PC) susceptibility. Here, we analyze 3,796 individuals in 263 PC families recruited as part of the ongoing Prostate Cancer Genetic Research Study (PROGRESS). We use Markov chain Monte Carlo (MCMC) oligogenic segregation analysis to estimate the number of quantitative trait loci (QTLs) and their contribution to the variance in age at onset of hereditary PC (HPC). We estimate 2 covariate effects: diagnosis of PC before and after prostate-specific antigen (PSA) test availability, and presence/absence of at least 1 blood relative with primary neuroepithelial brain cancer (BC). We find evidence that 2 to 3 QTLs contribute to the variance in age at onset of HPC. The 2 QTLs with the largest contribution to the total variance are both effectively dominant loci. We find that the covariate for diagnosis before and after PSA test availability is important. Our findings for the number of QTLs contributing to HPC and the variance contribution of these QTLs will be instructive in mapping and identifying these genes.

Molecular genetics of prostate cancer

The molecular mechanisms underlying the development and progression of prostate cancer are poorly understood. Epidemiological studies have suggested that 5-10% of all prostate cancers are familial, and numerous chromosomal loci have been associated with prostate cancer in multicentre linkage studies. However, no putative susceptibility genes harboured in these chromosomal regions have thus far been identified. Several recurrent chromosomal alterations in prostate cancer have been detected in comparative genomic hybridization (CGH) and loss of heterozygosity (LOH) analysis. The target genes for many of these aberrations are still not known. It seems that the androgen receptor (AR) signalling pathway plays a crucial role in both early development as well as in late progression of the disease. Both germ-line and somatic genetic alterations in the AR gene have been demonstrated in prostate cancer patients. The intention of this review is to summarize the current knowledge of molecular mechanisms in the development of prostate cancer.