SP7 and osteosarcoma: Analysis of SHH expression in human osteosarcoma cell lines, U2OS and MG63 by Western blot showed that while active SHH amino-terminal peptide was expressed at low levels in whole cell lysates, expression was markedly upregulated in xenograft tumor lysates, and in lysates obtained from the Osx p53Rb KO cell line D12M allograft tissues (Fig. 4f).