sentences:  We have therefore examined the influence of BTC upon mesenchymal stem cell (MSC) and pre-osteoblast differentiation and proliferation.BTC decreases the expression of osteogenic markers in both MSCs and pre-osteoblasts increases in proliferation require hypoxia-inducible factor-alpha (HIF-alpha), as an HIF antagonist prevents BTC-driven proliferation.Both MSCs and pre-osteoblasts express EGF receptors ErbB1, ErbB2, and ErbB3, with no change in expression under osteogenic differentiation.