Co-inheritance of breast and prostate cancer in a pedigree with large family data

Abstract: The connection between breast and prostate cancer in relatives within a family is an intriguing question in the field since this information is valuable when diagnosing patients with either type of cancer as it may contribute to cancer prevention. The aim of the thesis is to ascertain whether these two cancers are inherited together. Markov Chain Monte Carlo estimation is used with the MCMCglmm package in R. The data used was the Minnesota Breast Cancer Study with up to five generations in families. The data consists of 28081 individuals in 426 families. Results show that the heritability for prostate cancer is 65% and 34% for breast cancer in the liability scale, regardless of other factors that may increase the risk of these cancers. The odds ratio of having breast cancer given the brother has prostate cancer is increased 1.59 times whilst the odds ratio of having prostate cancer given the sister has breast cancer is 1.58 times. This information can undoubtedly be useful to doctors to enable them to prevent the disease by bearing in mind the family history of both cancers.