Prostate Cancer In Family

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Prostate cancer is one of the most common cancers among men, in both Western developed countries and worldwide (Ferlay 2008). It is a cancer that is only limited to males, as only males have prostate glands. The exact etiology is still unknown; however, it is thought to be a multifactorial disease with inherited genetics playing a major role (Xu 2013). Particularly, people with fathers and brothers with prostate cancer are at increased risk for developing it themselves. Other male relatives have also shown a linkage, especially if the relative was diagnosed young (Al Olama AA 2014). This report discusses how prostate cancer aggregates in family, via the analyses of heritability, twin and adoption studies, family pedigrees, and how specific…show more content…
A positive history of prostate cancer in a family results in 2- to 4-fold increased risk of disease (Adami 2008). However, the exact causes of prostate cancer still remain unclear. Family and twin studies have been used to further extrapolate the etiology and causal components of the disease (Lichtenstein 2000). “According to the Swedish Family-Cancer Database, 20.2% of men up to age 72 years diagnosed with prostate cancer have a paternal or fraternal family history, which is higher than that for breast (13.6%) or colorectal (12.8%)” (Hemminki 2012). It is estimated that 42% of the variation of liability to prostate cancer is the result of genetic variation (Lichtenstein 2000 & Baker 2005). This heritability factor is also further corroborated with genome-wide studies, where 70 susceptibility loci have been confirmed. Each locus only accounts for a small part of the familial risk but together combines for an estimated 30% (Lichtenstein 2000 & Kiciński 2011) to 38.9 % (AA Al Olama 2015) familial risk (Lichtenstein 2000 & Kiciński 2011). Dizygotic twins (which are genetically as similar as siblings) have a 20% probability of developing prostate cancer if the twin also had prostate cancer. This effect is almost twice as great as the general population (Hemminki 2012). Adoption studies are typically used to compare environmental effects versus genetic effects (AA Al Olama 2015). It was…show more content…
These studies compare allele/genotype frequencies of SNPs between population cases and controls. The low-penetrance genes of prostate cancer found are the following: Amundadottir and colleagues found a loci at 8q24 (Amundadottir 2006) with the strongest associated SNP as rs1447295 with a relative risk (RR) for prostate cancer estimated at 1.72. This finding was later corroborated with the results of the first two GWAS of prostate cancer in May 2007 (Amundadottir 2006 & Gudmundsson 2007). These initial GWAS studies analyzed 550,000 SNPs across the genome in cases and controls of European origin nested from the Cancer Genetic Markers of Susceptibility (Gudmundsson 2007). Yeager and colleagues confirmed the prostate cancer association with rs1447295 and identified another independent association at 8q24 (rs6983267). The estimated RRs were 1.26 and 1.58 for heterozygous and homozygous carriers, respectively (Yeager 2007). Gudmundsson and colleagues identified another new prostate cancer association at 8q24 (rs16901979). The estimated RR was 1.79 (Gudmundsson 2007). Two independent loci at 17q12 and 17q24 were also found (Gudmundsson 2007). Duggan and colleagues found one locus at 9q33 (Duggan 2007). Thomas and colleagues found four novel loci at 7p15, 10q11, 10q26 and 11q13 (Thomas 2008).
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