A Correlated Frailty Model with Long-Term Survivors for Estimating the Heritability of Breast Cancer

Isabella Locatelli, Università Bocconi
Alessandro Rosina, Università Cattolica
Paul Lichtenstein, Karolinska Institutet
Anatoli Yashin, Max Planck Institute for Demographic Research

The aim of this study is to investigate the role of genetics and environment in the susceptibility towards breast cancer. In order to do this, we adopt an interdisciplinary approach, combining a correlated frailty model with models developed by quantitative genetics. These ones enable to decompose the estimated variability of frailty into its genetic and environmental components. The methodology is applied to breast cancer data from the Swedish Twin Registry, including information about all the female monozygotic and dizygotic twin pairs born in Sweden between 1886 and 1967. Our estimate of heritability in the propensity to develop a breast cancer is obtained taking into account the possibility that a fraction of the population is not susceptible to experience the event. The inferential problem is solved in a Bayesian framework and the numerical work is carried out using MCMC techniques. Possible extensions, advantages and limitations of the proposed method are discussed.