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There were errors in multiple equations in the article. On the left side of all "conditional distribution" equations (located in the second paragraph of the "Statistical model" section of the Methods), the "vector" terms "x,""α,"σ," and "ϒ" are not correctly bolded. In the first listed of these equations, the power "-1" should refer to the term "c," not the term "ϒ" as is currently indicated. In the first-listed of these equations, there is an unnecessary space between the right bracket and the last term "2". In the fourth-listed of these equations, the power "s" should refer to the term "ϒ," not the term "1" as currently indicated. In the fifth-listed of these equations, the power "n-s" should refer to the term "ϒ," not the term "2" as currently indicated. In the sentence introducing these equations, the word "where" and the term "c" are incorrectly joined, and spaces were incorrectly inserted before the second, third and fourth pairs of brackets.

Studies on familial aggregation of cancer may suggest an overall contribution of inherited genes or a shared environment in the development of malignant disease. We performed a meta-analysis on familial clustering of prostate cancer. Out of 74 studies reporting data on familial aggregation of prostate cancer in unselected populations retrieved by a Pubmed search and browsing references, 33 independent studies meeting the inclusion criteria were used in the analysis performed with the random effects model. The pooled rate ratio (RR) for first-degree family history, i.e. affected father or brother, is 2.48 (95% confidence interval: 2.25-2.74). The incidence rate for men who have a brother who got prostate cancer increases 3.14 times (CI: 2.37-4.15), and for those with affected father 2.35 times (CI: 2.02-2.72). The pooled estimate of RR for two or more affected first-degree family members relative to no history in father and in brother is 4.39 (CI: 2.61-7.39). First-degree family history appears to increase the incidence rate of prostate cancer more in men under 65 (RR: 2.87, CI: 2.21-3.74), than in men aged 65 and older (RR: 1.92, CI: 1.49-2.47), p for interaction = 0.002. The attributable fraction among those having an affected first-degree relative equals to 59.7% (CI: 55.6-63.5%) for men at all ages, 65.2% (CI: 57.7-71.4%) for men younger than 65 and 47.9% (CI: 37.1-56.8%) for men aged 65 or older. For those with a family history in 2 or more first-degree family members 77.2% (CI: 65.4-85.0%) of prostate cancer incidence can be attributed to the familial clustering. Our combined estimates show strong familial clustering and a significant effect-modification by age meaning that familial aggregation was associated with earlier disease onset (before age 65). The study was supported by Scientific Fund FWO (URL: www.fwo.be, krediet aan navorsors; 1.5.158.09.N.00), and Michal Kiciński has a Ph.D. fellowship of the Research Foundation – Flanders (FWO). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.