Joachim Weischenfeldt says: “The life history of a cancer is initiated and propagated by mutations. Identifying the earliest mutagenic processes that may ultimately lead to treatment resistance is of major clinical relevance for a more precise diagnosis and prognosis. Cancer cells are known to interact and evolve in time and space, through interactions with the local environment and through constant evolution. This is true for prostate cancer, the most common non-skin cancer in men. The disease is proposed to arise through interactions with tumor-promoting cells and factors in the tumor microenvironment of the prostate that cause a mutagenic “field effect“, which can impact large areas of the prostate. We aim to identify the earliest mutational processes and examine how tumor clones evolve and compete by using novel single-cell based methodologies combined with tumor evolution tracing in patients, with the overarching goal to identify early markers that can predict clinical trajectories of aggressive disease.”