The cancer-driving HRas-mutant basal cells were deficient for Wnt signalling, but recruited the HRas-wildtype luminal cells to secrete Wnt1 to drive biclonal primary tumour growth.66,67 However, breast cancer subclones can cooperate not only with neighbouring clones in the same primary tumour, but also with cancer cells in metastatic lesions. This evidence concerns the gene WNT1 and cancer.