The landscape of somatic mutation in normal colorectal epithelial cells

The colorectal adenoma–carcinoma sequence has provided a paradigmatic framework for understanding the successive somatic genetic changes and consequent clonal expansions that lead to cancer1. However, our understanding of the earliest phases of colorectal neoplastic changes—which may occur in morphologically normal tissue—is comparatively limited, as for most cancer types. Here we use whole-genome sequencing to analyse hundreds of normal crypts …