PJA1 and cancer: However, 2 mice from total 6 mice injected with LSCs from the PJA1-injected TGF-β-defective (Smad3+/-) mice formed tumors and liver metastases, suggesting that increased PJA1 in the context of defective TGF-β signaling promotes liver stem cell properties and their transformation into cancer stem cells (Figure 1) [22].