MIB1 and hepatocellular carcinoma: When we correlated the SLC22A1 immunoreactivity score with clinicopathological characteristics, a significant inverse correlation was found only for the MIB1/Ki-67 proliferation rate (rs = -0.464, P < 0.0001), which was determined in HCC tissue samples by immunohistochemical staining as previously described (Figure S2A in Additional file 1) [18].