We will review these processes by describing the expression profile of ESE factors in normal tissues, focussing on the phenotypes of ESE factor knockout mice which have been described in detail for Elf3, Elf5 and Spdef. ESE factors have also been implicated in the pathogenesis of a wide range of cancers, with both oncogenic and tumour suppressive roles described depending on the specific ESE factor and tumour type. The gene discussed is ELF5; the disease is cancer.