TGFB1 and cancer: Importantly, in healthy human cells (keratinocytes) expressing barely detectable amounts of galectin-9, TGF-β cannot induce galectin-9 expression, while if cancer cells (for example K562 chronic myeloid leukaemia cells) express only traces of galectin-9, TGF-β can induce expression of this protein (Figure 8 and Supplementary Figure 2).