Pogo transposons provide tools to restrict cancer growth.

Transposable elements provide material for novel gene formation. In particular, DNA transposons have contributed several essential genes involved in various physiological or pathological conditions. Here, we discuss recent findings by Tu et al. in Molecular Cell that identify Pogo transposon-derived gene POGK as tumor suppressor in triple-negative breast cancer (TNBC) by regulating ribosome biogenesis and restricting cell growth. An isoform-switch in TNBC results in the loss of POGK capacity to recruit the epigenetic corepressor TRIM28 and to exert its repressive functions. These findings shed light on the potential for TE-derived genes in providing new therapeutic opportunities for highly malignant TNBC.