Using polyclonal breast cancer models, it has been shown that low-represented minor sub-populations expressing IL-11 (interleukin 11) and FIGF (Fos-induced growth factor) can drive tumour growth in other sub-clones and promote metastasis in a non-cell-autonomous manner apparently by modifying the local microenvironment [174,175]. This evidence concerns the gene IL11 and breast carcinoma.