For example, absence of PKM2 accelerates tumor formation in a Brca1-loss-driven model of breast cancer [40], in a mouse model of medulloblastoma [52], and results in spontaneous hepatocellular carcinoma (HCC) development in aged mice [53], indicating that PKM2 negatively regulates tumorigenesis. Here, BRCA1 is linked to hepatocellular carcinoma.