However, it is important to note that DKK4 mRNA and protein levels did not correlate in the SRC-2 gain-of-function (Fig 4) and loss of function studies (Fig 6), and that overexpression of DKK4 alone was insufficient to rescue the tumor burden of SRC-2 knockdown in HepG2 cells (S9 Fig). The gene discussed is DKK4; the disease is neoplasm.