BSG and hepatocellular carcinoma: DNA methylation in the CD147/BSG 5′ gene promoter in cohort 3 was investigated by a newly established MALDI-TOF MS assay in a region identified by Kong et al, which has been shown to be important for CD147 transcription and which has already been shown to be differentially expressed in hepatocellular carcinoma (HCC) compared to normal liver tissue due to aberrant DNA methylation [15].