FCF1 and cancer: ADPRHL1, FADS3, FCF1, FIS1, GIGYF1, HDAC10, KLC2, STRN4 and TAF6 were expressed at least in one CTC sample and showed a trend toward higher expression values in the CTC population compared to cancer cells at primary site (Fig. 2F; plot of individual gene expression data in Supplementary Fig. S2, panel D), thus supporting findings arising from gene expression analysis of CTC models obtained in the MDA-MB-231 xenograft, and suggesting that CTC profile hides a different message compared to the primary tumor.