AQP1 and osteosarcoma: Gene set enrichment analysis performed by Wu and colleagues indicated a positive correlation between AQP1 over-expression and TGF-β signalling pathway in osteosarcoma and expression of TGF-β1 and TGF-β2 was reduced in U2OP and MG63 cell lines when their AQP1 expression was down-regulated by shRNA [66].