Cells change identity during embryonic development, and the same transitions are hijacked in disease. Both depend on the cis-regulatory code that tells a gene when, where and how strongly to be expressed. We still lack a clear understanding of how enhancers cooperate, how they integrate signalling and transcription factor inputs, and how this logic is rewired in pathological contexts.

The epithelial-to-mesenchymal transition (EMT) is a natural framework for these questions. It is required for normal morphogenesis, and its misregulation in cancer drives progression and metastasis. We approach it from two complementary angles: embryo models, where we can follow and perturb cell fate decisions in a controlled developmental context, and cancer models, where we ask how the same transition becomes dysfunctional. In this talk, we will show how our combined approaches converge on shared principles of enhancer-driven cell identity change. We will also show how they highlight differences between functional and pathological transitions, and how this understanding can help us engineer better models of embryos and diseases and develop new therapeutic strategies.