Researchers found that platelet-derived TGF-β contacts with platelet-tumor cells and co-activates the TGF-β/Smad and NF-κB pathways in CTCs, leading to the transition to an invasive mesenchymal-like phenotype and enhancing the metastasis of cancer cells in vivo (Labelle et al. 2011). The gene discussed is TGFB1; the disease is cancer.