New Genetic Variants Linked with Risk of Prostate Cancer

21 September 2009 Filed under Cancer research, Genes, Prostate Cancer Posted by » Comments Off

Scientists have identified seven new genetic variants that appear to be linked with increase risk of prostate cancer. Among these are four new “single-letter” genetic variants on one particular chromosome, called 8q24.

This chromosomal region has previously been associated with breast, colon, and bladder cancer. The discoveries identifying the four new genetic locations associated with prostate cancer on chromosome 8q24 were made by teams of independent scientists around the world. Three separate research papers on the discoveries are published in the online issue of Nature Genetics.

In one of the papers, Rosalind Eeles, from the London, UK Institute of Cancer Research laboratory (ICR) and colleagues in the Genetic Epidemiology Unit, University of Cambridge, report on the discovery of seven new prostate cancer susceptibility loci. In this video Dr. Eeles explains what her team found. She says they plan to take the results “into the clinic” to try to predict which men may need early testing for prostate cancer. Dr. Eeles says 8q is a “very interesting part of the genome for solid cancer risk.”

Another part of the work was done by a collaboration among scientists at deCODE, the Icelandic genetics company, and their international colleagues from Finland, Spain, the Netherlands and the United States.

First of all they identified the four novel prostate cancer-related SNPS including one involving 8q24. The third study, by the ICR researchers in collaboration with scientists at Cancer Research U.K.’s Genetic Epidemiology Unit, University of Cambridge, homed in on 8q24, and was able to confirm associations at three previously reported loci on the chromosome and identify additional loci in two other linkage disequilibrium blocks that were associated with prostate cancer.

The study authors calculate share of risk from family-related prostate cancer for men who have one of the newly discovered genetic variants as follows: assuming an overall twofold familial relative risk for men with first-degree relatives of prostate cancer (e.g. father or brother), and assuming also that the SNPs combine multiplicatively, then “the newly associated loci reported here together explain about about 4.3% of the familial risk of prostate cancer. Including the previously reported loci, about 21.5% of familial risk in prostate cancer may now be explained.”

“Under this model the top 10% of the population at highest risk for prostate cancer has a relative risk about 2.3-fold greater than the average risk in the general population, whereas the top 1% has an estimated three­fold increased relative risk.”

“Shares of Decode Genetics stock were up nearly 11 percent in trading today following Decode researchers’ identification of new prostate cancer risk variants,” according to a genetics news source.


Why is this chromosome called 8q24?

“The ‘q’ refers to the long arm of the chromosome. A prototypical condensed chromosome has two arms: a short arm and a long arm. The ‘p’ stands for the French word ‘petit’ (which means small). The ‘q’ doesn’t stand for anything in particular, but because ‘q’ comes after ‘p’ in the alphabet, it is used to refer to the long arm of the chromosome. Wiki Answers

What is a SNP?

A single-nucleotide polymorphism (SNP, pronounced snip) is a DNA sequence variation occurring when a single nucleotide — A, T, C, or G — in the genome (or other shared sequence) differs between members of a species (or between paired chromosomes in an individual). For example, two sequenced DNA fragments from different individuals, AAGCCTA to AAGCTTA, contain a difference in a single nucleotide. In this case we say that there are two alleles : C and T. Almost all common SNPs have only two alleles.

Nature Genetics
Published online: 20 September 2009
Identification of seven new prostate cancer susceptibility loci through a genome-wide association study

Nature Genetics
Published online: 20 September 2009
Genome-wide association and replication studies identify four variants associated with prostate cancer susceptibility

Nature Genetics
Published online: 20 September 2009
Identification of a new prostate cancer susceptibility locus on chromosome 8q24

Nature Genetics
Published online: 20 September 2009 |
Multiple loci on 8q24 associated with prostate cancer susceptibility

“>deCODE genetics, Inc is a biopharmaceutical company based in Reykjavík, Iceland.
The company was founded in 1996 to identify human genes associated with common diseases using population studies, and to apply the knowledge gained to guide the development of candidate drugs. So far the company has isolated genes believed to be involved in cardiovascular disease, cancer and schizophrenia, among other diseases. deCODE set up an Icelandic Health Sector Database (HSD) containing the medical records and genealogical and genetic data of all Icelanders. This has been very controversial and has received criticism for its approach to the ethics of privacy and consent. In 2003 the Icelandic Supreme Court in November 2003 made a judgment that effectively ended the database project. In 2004 a SEC filing revealed that deCODE had never made a profit and their net losses to date were over 530 million dollars. In fall 2008 the Icelandic economy, hard hit by worldwide recession, crashed.

The Institute of Cancer Research is one of the world’s leading cancer research organisations and is internationally renowned for the quality of its science.

The ICR is a college of the University of London and works in partnership with The Royal Marsden NHS Foundation Trust.
Cash-Starved deCODE Is Looking For a Rescuer for Its Biobank
Jocelyn Kaiser

Functional studies of a cancer risk variant located in gene desert
30 July 2009 | By Dr Caroline Wright

deCODE’ing Predisposition to Cancer cancer-genetics blog, November 17, 2007


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