Super competition as a possible mechanism to pioneer precancerous fields

Cancer is the result of sequential genetic changes over time that transform a cell into a malignant and ultimately invasive entity. The insight that cancerous cells arise from a series of mutations in oncogenes and tumor suppressors, commonly known as multistep carcinogenesis, has been conceptually elaborated and proven in the last 20 years. Although knowledge about late steps of cancerogenesis and disease progression has greatly advanced, the initial molecular events remain largely unknown. Basic research in Drosophila has started the quest to find early markers that detect initial clonal expansion of precancerous cells. These efforts were spurred by novel findings demonstrating that certain mutations transform cells into super-competitors that expand at the expense of the surrounding epithelial cells without inducing histological changes. This mechanism, discovered as super competition in the fly, might also lie at the heart of a clinical observation termed 'field cancerization'. This review aims to bring together current understanding from basic research on cell competition and clinical studies that have analyzed field characteristics to highlight parallels and possible connections.