Interestingly, tumor cell-secreted GRP78 was shown to induce the differentiation of bone marrow mesenchymal SCs into cancer-associated fibroblasts (CAFs); such CAF-generating differentiation seemed to be due to activation of the TGFβ/Smad signaling pathway by external (tumor-derived) GRP78 [248]. The gene discussed is TGFB1; the disease is cancer.